Nerve supply?All parts by ansa cervicalis C1 to C3 except for thyrohyoid which is innervated by C1
Action?Depress the hyoid bone and larynx during swallowing and speaking
Identify spinal accessory nerve?
Supplies?• Trapezius (shrug the shoulder) • Sternomastoid (turns the head to the contralateral side)
Surface anatomy?It crosses the posterior triangle of neck between the point of the junction between upper ⅓ and lower ⅔ of the sternomastoid to the junction between upper ⅔ and the lower ⅓ of the trapezius
Identify great auricular nerve?Supply? (C2, C3) • Skin over the angle of the mandible • Skin over the parotid gland • Skin of the lower ½ of the auricle
Identify external carotid artery?
Course?Origin: as one of the 2 terminal branches of CCA at the upper border of the thyroid cartilage (C4) Termination: behind the neck of the mandible inside the parotid gland by dividing into superficial temporal and maxillary branches
Nerve passing anterior to it?Hypoglossal nerve
Branches?It has six main branches, three in front, two behind and one deep. Three in front Superior thyroid Lingual Facial Two behind Occipital Posterior auricular Deep Ascending pharyngeal 'Some Angry Lady Figured Out PMS' (in order) Superior thyroid (superior laryngeal artery branch) Ascending pharyngeal Lingual Facial (tonsillar and labial artery) Occipital Posterior auricular Maxillary (inferior alveolar artery, middle meningeal a.) Superficial temporal Occipital artery Superior thyroid artery External carotid artery Internal carotid artery Ascending pharyngeal artery
Carotid body?On the posterior aspect of the bifurcation of CCA contains chemoreceptors sensitive to changes in pH.
Carotid sinus?The carotid sinus is a dilated area at the base of the internal carotid artery just superior to the bifurcation of the internal carotid and external carotid at the level of the superior border of thyroid cartilage. It contains baroreceptors for maintaining blood pressure.
Identify left and right lobes and isthmus?
Arterial supply and venous drainage?Arterial • Superior thyroid artery (1st branch of external carotid) • Inferior thyroid* artery (from thyrocervical trunk from subclavian a. 1st part) • Thyroidea ima (in 10% of population -from brachiocephalic artery or aorta) Venous • Superior and middle thyroid veins - into the IJV • Inferior thyroid vein - into the brachiocephalic veins * Also supplies parathyroid glands
Lymphatic drainage?Pre-laryngeal, pre-tracheal, para-tracheal, upper and lower deep cervical, brachiocephalic lymph nodes.
Embryology of thyroid?The thyroid gland develops from the foramen caecum (⅔ along the length of tongue from the tip) to pass forward and loop around beneath the hyoid bone. Incomplete descent → lingual or pyramidal thyroid Incomplete closure of the pathway of descent → thyroglossal cyst
Vertebral level of thyroid cartilage?C4
Why thyroid moves up with deglutition?As the thyroid gland present within the pretracheal fascia which is attached to the thyroid cartilage and hyoid bone. When the digastric muscle contract it pulls the hyoid bone upward which pulls the thyroid cartilage which pulls the pretracheal fascia with its contents.
Show the veins draining the thyroid?
Show the artery supplying the thyroid?Right recurrent laryngeal nerve Pretracheal fascia Trachea Pyramidal lobe Right internal jugular vein Thyroid gland Left lobe thyroid Common carotid artery Left internal jugular vein A thyroglossal cyst is a fibrous cyst that forms from a persistent thyroglossal duct. Thyroglossal cysts can be defined as an irregular neck mass or a lump which develops from cells and tissues left over after the formation of the thyroid gland during developmental stages.
Commonly injured nerves during thyroidectomy?• ELN (close to the superior thyroid artery) • RLN (close to the inferior thyroid artery) • Cervical sympathetic chain (lateral ligature of the inferior thyroid artery trunk causing ischemia induced neural damage)
Type of thyroid cancer which spreads via the lymphatic route?Papillary thyroid cancer is the only type to which spread via the lymphatic route
Cell origin of medullary carcinoma?Parafollicular C cells
Late complications of thyroidectomy?• Hypothyroidism • Hypocalcemia Parathyroid
Location?On the posterior aspect of the thyroid gland 2 on each side
Hormone secretion?Parathormone which plays a role in calcium homeostasis
Embryology?• Inferior parathyroid from the 3rd branchial arch with the thymus • Superior parathyroid from the 4th branchial arch
Blood supply?Inferior thyroid artery Left subclavian artery Right recurrent laryngeal nerve Thyrocervical trunk Inferior thyroid a. Inferior thyroid veins Thyrohyoid
Nerve supply?• Motor: All laryngeal muscles are supplied by RLN except for cricothyroid muscle, which is supplied by the external laryngeal nerve (ELN) (branch of SLN which is a branch of vagus) • Sensory: Above vocal cord: Internal laryngeal nerve (ILN) (branch of SLN which is a branch of vagus) Below vocal cord: RLN (from vagus)
Muscles responsible opening vocal cords?By the 2 posterior cricoarytenoid muscles by externally rotating the arytenoids
Muscles responsible for closing the larynx during swallowing?By lateral cricoarytenoid muscle
Muscles responsible for tensing vocal cords?By the 2 cricothyroid muscles
Site of cricothyroidotomy?Cricothyroid membrane (between thyroid and cricoid cartilage) Action of the posterior cricoarytenoid muscles Action of the lateral cricoarytenoid muscles
Supply?Supplies all laryngeal muscles except cricothyroid muscle (supplied by SLN) Sensory innervation of the mucous membranes of the larynx below the vocal cords
Injury on one side (unilateral) during thyroidectomy may lead to?• Diplophonia, hoarseness of voice • Dysphagia Bilateral injury may lead to? Semon’s Law • Partial (adducted cords): Respiratory compromise • Full (½ ab(ad)ducted): Aphonia, inability to speak or cough Right vagus ne Inferior vagal ganglion Superior laryngeal nerve Internal laryngeal nerve Right recurrent laryngeal Cricothyroid muscle Left recurrent laryngeal External laryngeal nerve Ligamentum arteriosum Left pulmonary artery Branches of Superior laryngeal nerve • External laryngeal nerve “motor” • Internal laryngeal nerve “sensory” Damage to SLN • Abnormalities in pitch • Inability to sing with smooth change to each higher note (glissando or pitch glide)
What are diploic veins?Veins found in the skull that drain the diploic space to the dural venous sinus
Tear to which vessel might cause subdural haematoma?Cerebral vein and bridging veins Layers of the scalp - SCALP
Type of temporomandibular joint?Bi-arthrodial hinge joint (synovial)
Articulating surfaces of TMJ?• Head of the mandible • Mandibular (Articular) fossa of the temporal bone • Articular tubercle (from squamous part of the temporal bone)
Movements of TMJ?• Elevation • Depression* • Protrusion* • Retraction • Side to side *Opening (protrusion + depression) By DLGM: Digastric, Lateral pterygoid, Geniohyoid, Mylohyoid Temporomandibular joint. A. Mouth closed. B. Mouth open. Movements of the temporomandibular joint
Boundaries?Anterior: • Lesser wing of sphenoid • Anterior clinoid process Posterior: • Petrous part of temporal bone • Dorsum sellae Laterally • Squamous part of the temporal bone
Contents?The temporal lobe
Boundaries of the posterior cranial fossa?• Anterior: The apex of the petrous part of the temporal bone • Posterior: Occipital bone • Lateral: Squamous + mastoid parts of the temporal bone
Bones forming posterior cranial fossa?Occipital bone + temporal bone MIDDLE CRANIAL FOSSA ANTERIOR CRANIAL FOSSA POSTERIOR CRANIAL FOSSA
Draining blood from?• Superior ophthalmic veins • Facial vein • Emissary veins from pterygoid plexus. • Sphenoparietal sinuses
Contents?“O TOM CAT” Lateral wall components (from top to bottom:) Oculomotor nerve (III) Trochlear nerve (IV) Ophthalmic nerve (V1) Maxillary nerve (V2) Contents of the sinus (from medial to lateral:) Internal Carotid artery (and sympathetic plexus) Abducens nerve (VI)
Drains blood to?• Superior and inferior petrosal sinuses. • IJV • Intercavernous sinus
Clinical significance?Cavernous sinus thrombosis Due to infections from the dangerous area of the face (drained by ophthalmic and facial veins) may spread to the cavernous sinus as the draining veins are valveless
Signs of thrombosis?• Painful swelling of the eye • 3rd, 4th, 5th, 6th cranial palsies • Gradual loss of vision Cavernous sinus syndrome is most commonly caused by cavernous sinus tumors. Diagnosis is based on signs of pain, ophthalmoplegia, proptosis, trigeminal nerve lesion (ophthalmic branch) and Horner's syndrome.
What is the major vein draining the brain parenchyma?Great Cerebral vein Describe blood flow from the superior sagittal sinus to the IJV See table Describe the location of the straight sinus Tentorium cerebelli and flax junction
Show transverse sinus and sigmoid sinus on skull bone model?See pic
Identify temporalis muscle?
Blood supply?Deep temporal arteries (anterior and posterior) from maxillary artery
What supplies the scalp over the temporalis muscle?Superficial temporal artery from ECA Temporalis muscle
Intracranial course of facial nerve?Origin between pons and medulla → IAM → facial canal (petrous part of temporal bone) → exit through the stylomastoid foramen
Branches in the face?Enters parotid gland and divides into 5 branches: “The Zebra Buggered My Cat” • Temporal branch • Zygomatic branch • Buccal branch • Marginal mandibular branch • Cervical branch
Cranial nerves that transmit parasympathetic fibers?The only cranial nerves that transmit parasympathetic fibers are the Oculomotor (III), Facial (VII), Glossopharyngeal (IX), and Vagus (X) nerves Facial nerve [VII] on the face. A. Terminal branches. B. Branches before entering the parotid gland.
Identify parotid gland?
Identify parotid duct? Surface anatomy?The middle ⅓ of a line drawn between intertragic notch to the middle of the philtrum
Opening?Crosses the masseter, pierces the buccinator and drains adjacent to the 2nd upper molar tooth (Stensen's duct).
Structures passing through the gland?• Facial nerve (most superficial structure) (“The Zebra Buggered My Cat” Temporal Zygomatic, Buccal, Mandibular, Cervical) • External carotid artery • Retromandibular vein • Auriculotemporal nerve (from posterior trunk of V3) • Deep parotid lymph nodes Relations • Anterior: masseter, medial pterygoid, superficial temporal and maxillary artery, facial nerve, stylomandibular ligament • Posterior: posterior belly digastric muscle, sternocleidomastoid, stylohyoid, internal carotid artery, mastoid process, styloid process Arterial supply? Branches of external carotid artery Venous drainage? Retromandibular vein (union of the superficial temporal and maxillary veins) Lymphatic drainage? Deep and superficial parotid lymph nodes → upper deep cervical lymph nodes Nerve innervation
Surface anatomy?• Upper end: curved line from the tragus to the center of mastoid bone • Anterior border: a line from the tragus of the ear to the center of the posterior border of the masseter then to the point 2 cm below and behind the angle of the mandible • Posterior border: straight line from the mastoid process to a point 2cm below and behind the angle of the mandible
Type of parotid salivary secretions?Serous Parasympathetic stimulation produces a water-rich, serous saliva. Sympathetic stimulation leads to the production of a low volume, enzyme-rich saliva.
Differential diagnosis of parotid lump?• Infection (parotitis, mumps) • Obstructed duct (calculus or external compression) • Neoplasm (pleomorphic adenoma, Warthin’s tumor) • Deep parotid lymph nodes
Frey syndrome?Damage of the parasympathetic fibers from the auriculotemporal nerve resulting in excessive gustatory sweating in response to salivary stimulus Parotid gland and duct, CN VII & XI, cutaneous branches of cervical plexus and internal jugular vein. 1) porion line; 2) zygomatic sutural line; 3) zone of location of the (fronto)temporal nerve; 4) parotid gland; 5) zone of location (white) of the parotid duct (green line): sits within 1.5 cm of the middle half of a line passing from the lower tragus to the chelion; 6) lower tragus–chelion line; 7) marginal mandibular nerve; 8) zone of emergence of the cutaneous branches of the cervical plexus (white), posterior to the middle third of sternocleidomastoid; 9) zone of location of the accessory nerve, from 3–10 cm below the tip of the mastoid process to 1–10 cm above the insertion of trapezius into the clavicle; 10) hyoid bone; 11) thyroid cartilage (laryngeal prominence); 12) cricothyroid ligament/membrane;
Where to palpate facial artery?Can be palpated as it crosses the inferior border of the mandible adjacent to the anterior border of the masseter
Submandibular duct opening?Opens in the floor of the mouth on either side of the lingual frenulum
Submandibular gland type of secretion?Mucous + serous
Nerves at risk of injury on submandibular gland excision?• Lingual nerve (above) • Hypoglossal nerve (below) → deviation of the tongue to the affected side on protrusion • Marginal mandibular branch of facial nerve
Difference between UMNL and LMNL facial palsy?In upper motor neuron lesion upper part of face will be spared (only lower part will be affected) In lower motor neuron lesion both upper and lower part of face will be affected.
Regions drained by pre-auricular LNs?• Upper half of the face • Temporal region • Auricle and external auditory meatus • Gums
Identify this picture?Microscopic picture of malignant melanoma lymph node metastasis (note pigmented cells)
Nerve supply?Motor Innervation All of the motor innervation is provided by Hypoglossal (XII) except for the palatoglossus muscle which is provided by Vagus (X). Sensory and taste Innervation Area Sensory Innervation Gustatory (taste) Innervation Posterior part of the root of tongue Vagus (X) Posterior 1/3 Glossopharyngeal (IX)* Anterior 2/3 Mandibular (V3) via Lingual Facial (VII) via Chorda tympani *Supplies general sensation to the posterior third of the tongue and contributes to the gag reflex. Extrinsic muscles of the tongue? SHPG Muscle Innervation Elevate Depress Retract Protrude Styloglossus Hypoglossal ✔ ✔ Hyoglossus Hypoglossal ✔ ✔ Genioglossus Hypoglossal ✔ ✔ Palatoglossus Vagus ✔
Muscle retracting the tongue?Styloglossus
Nerve supply?All by hypoglossal nerve except for the palatoglossus by vagus nerve Palatoglossus vagus nerve [X] Motor Hypoglossal nerve [XII] Sensory Anterior two-thirds (oral) • General sensation mandibular nerve [V3] via lingual nerve • Special sensation (taste) facial nerve [VII] via chorda tympani Posterior one-third (pharyngeal) • General and special (taste) sensation via glossopharyngeal nerve [IX] Genioglossus Intrinsic muscle Chorda tympani (from [VII]) Lingual nerve (from [V3]) Deep lingual vein Dorsal lingual vein Lingual artery Common carotid artery Internal jugular vein Sternocleidomastoid branch of occipital artery Glossopharyngeal nerve [IX]
Roof of the middle ear?Tegmen tympani
How middle ear infections cross the skull?By direct erosion of tegmen tympani It may also spread to mastoid air cells causing mastoiditis
Clinical picture of meningism?• Photophobia • Neck stiffness • Fever
Identify Internal auditory meatus (IAM)?
Structures passing through IAM?• Facial nerve • Vestibulocochlear nerve
What can make irreversible damage to vestibulocochlear nerve?Acoustic neuroma
Why patient with acoustic neuroma hear sounds loudly on affected side?Affection of facial nerve with paralysis of stapedius
Relations of the middle ear?• Roof (Tegmental wall): Tegmen tympani; separates tympanic cavity from MCF • Floor (Jugular wall): Thin bone separates tympanic cavity from superior bulb of IJN • Anterior wall: Thin bone; separates tympanic cavity from ICA and at its upper part are openings into two canals (auditory tube and canal for tensor tympani) • Posterior wall (mastoid wall): Aditus to the mastoid antrum superiorly and pyramid inferiorly (for stapedius) • Lateral wall (membranous wall): Tympanic membrane (doesn’t extend superiorly) and lateral wall of epitympanic recess (superiorly) • Medial wall: Lateral wall of the inner ear Round window Internal carotid artery Tensor tympani muscle Tegmen tympani Promontory Prominence of facial canal Prominence of lat. Semicircular canal Aditus to mastoid antrum Tympanic branch of glossopharyngeal nerve [IX] Internal jugular vein Chorda tympani Facial nerve Boundaries of the right middle ear
Arnold Chiari malformations?It is a condition affecting the brain. It consists of a downward displacement of the cerebellar tonsils through the foramen magnum causing non-communicating hydrocephalus as a result of obstruction of cerebrospinal fluid (CSF) outflow. Arnold-Chiari malformation. Midsagittal section showing small posterior fossa contents, downward displacement of the cerebellar vermis, and deformity of the medulla (arrows indicate the approximate level of the foramen magnum).
Identify parasagittal hyperdense mass?Meningioma
Where does it arise from?They arise from the arachnoid "cap" cells of the arachnoid villi in the meninges
What structures may it compress?• Superior sagittal sinus • Cerebral hemisphere
What structures does it lie between?Falx and cerebral hemisphere Identify corpus collosum and lateral ventricle and Precentral gyrus on MRI See before
What is the patient will be presented by?Monoparesis of the contralateral lower limb
What area of the brain is affected?Motor area 4
What area of body is represented on medial side of motor area?Lower limbs
What area is located in pre-central gyrus?Primary motor cortex
Which layer of meninges is meningioma attached to?Dura Type of contrast Gadolinium
What is meant by ring enhancement?Is an abnormal radiologic sing of MRI or CT scans obtained using radiocontrast. On the image, there is an area of increased density, surrounded by a bright rim from concentration of the enhancing contrast dye. This enhancement may represent breakdown of the blood-brain barrier and the development of an inflammatory capsule. Differential diagnosis? MAGIC DR • Metastasis • Abscess • Glioblastoma • Infarct (subacute phase) • Contusion • Demyelinating disease • Radiation necrosis or resolving hematoma
What is the aggressive form of glioma?Glioblastoma multiforme (GBM) CSF
Circulation of cerebrospinal fluid (CSF)?The arrows show the pathway of cerebrospinal fluid flow from the choroid plexuses in the lateral ventricles to the arachnoidal villi protruding into the dural sinuses. Lateral Ventricle Interventricular Foramen (Foramen of Monroe) Lateral Ventricle Interventricular Foramen (Foramen of Monroe) Third Ventricle Aqueduct of Sylvius (Cerebral Aueduct) Fourth Ventricle Foramen of Luschka (Lateral Aperture) Foramen of Magendie (Median Aperture) Foramen of Luschka (Lateral Aperture) Subarachnoid Space Arachnoid Villi Superior Sagittal Sinus
Entry of vertebral artery into the skull?Vertebral artery enters the skull through the foramen magnum Crosses transversely across the posterior arch of the atlas
Vertebral artery course?Inside the skull, the 2 vertebral arteries pass upwards, forwards and medially in the subarachnoid space to reach the anterior aspect of the medulla oblongata, then they unite together at the lower border of the pons to form the basilar artery
What the vertebral artery and basilar artery supply in the brain?The vertebrobasilar arterial system perfuse the medulla, cerebellum, pons, midbrain, thalamus, and occipital cortex
Which vein drain the dangerous area of the face?Inferior ophthalmic vein
Where does the ICA enter the skull / Course of the internal carotid artery?ICA enters the skull through the carotid canal in the petrous part of temporal bone
What branch gives off before ACA, MCA?Ophthalmic artery
Berry aneurysm rupture?Subarachnoid hemorrhage
Signs of MCA infarct?• Hemiplegia of the lower ½ of the contralateral face • Hemiplegia of the contralateral upper and lower extremities • Aphasia if in the dominant hemisphere
Sensory nerves in relation to internal carotid artery?• Trigeminal nerve branches (ophthalmic and maxillary nerves at the lateral wall of cavernous sinus) • Optic nerve
Identify vessels on cerebral angiogram?
Identify optic nerve, ICA, optic chiasm, oculomotor and abducent nerves?
Identify falx cerebelli and tentorium cerebelli?
Anterior attachment of tentorium cerebelli?Superior angle of the petrous part of the temporal bone Blood vessel supplying the inner table of temporal bone Middle meningeal artery
If there is a tumor in the precentral gyrus, what is the bone to penetrate?Parietal bone
Relationship between ICP and oculomotor?Increase in ICP → oculomotor nerve palsy → dilated pupil (see ASSCC)
What are false localizing signs?Neurological signs have been described as “false localizing” if they reflect dysfunction distant or remote from the expected anatomical locus of pathology. They occur in two major contexts: as a consequence of raised ICP, and with spinal cord lesions. E.g.: abducent nerve palsy due to ↑ ICP Internal carotid artery
Muscles supplied by oculomotor nerve?• Levator palpebrae superioris • Superior rectus • Inferior rectus • Medial rectus • Sympathetic fibres to Muller’s muscle • Inferior oblique • Sphincter pupillae
Paralysis of oculomotor nerve leads to?The eye will be displaced outward and downward • Outward because the lateral rectus (innervated by Abducens [VI]) maintains muscle tone in comparison to the paralyzed medial rectus. • Downwards, because the superior oblique (innervated by Trochlear [IV]) is un-antagonized by the paralyzed superior rectus, inferior rectus and inferior oblique. The affected individual will also have a ptosis and mydriasis
What is the exact structure on which the oculomotor nerve is pressed against?Petrous part of the temporal bone (attached border of tentorium cerebelli)
Structures passing through superior orbital fissure?See before (foramina) SO4 LR6 Superior oblique innervated by 4th (trochlear) Lateral rectus innervated by 6th (abducent) A. Action of individual muscles (anatomical action). B. Movement of eye when testing specific muscle (clinical testing).
Demonstrate where brachial plexus run on a subject?
Where are parts of brachial plexus found?• Roots: exits from IV foramina between scalenus anterior and medius • Trunks: base of the posterior triangle of the neck behind the 3rd part of the subclavian artery • Divisions: behind middle ⅓ of the clavicle • Cords: related to the 2nd part of axillary artery
Erb's paralysis?• Damage to the upper nerve roots (C5, C6) • Motor affection: (waiter’s tip deformity) o Paralysis of arm abductors (supraspinatus + deltoid) → arm adduction o Paralysis of arm external rotators (infraspinatus +teres minor) → arm internal rotation o Paralysis of forearm flexors and supinators (biceps, brachialis, brachioradialis) → forearm extension and pronation • Sensory affection: loss of sensation of radial side of arm and forearm
Klumpke’s paralysis?• Injury to lower trunk (C8, T1) • Motor affection: (claw hand deformity) o Paralysis of all intrinsic muscles of the hand o Paralysis of wrist flexors (except flexor carpi radialis) o Hyperextension of MCP joints with flexion of IP joints • Sensory affection: loss of sensation over ulnar border of forearm and hand
Pectoralis major, Trapezius, Serratus anterior and Deltoid?Muscle Origin Insertion Action Innervation Pectoralis major Clavicular head • From the medial half of the anterior surface of the clavicle Sternocostal head • Anterior surface of the sternum • Upper 6 costal cartilages • EOA Humerus (lateral ITG) (lateral lip of bicipital groove) • Adduction and medial rotation of the arm (the whole muscle) • Clavicular head: flexion of the arm • Sternocostal head: extends the flexed arm • Acts as accessory respiratory muscle by elevating the ribs Medial (C8- T1) and Lateral (C5- C7) pectoral nerves
Rotator cuff muscles?Muscle Origin Insertion Action Innervation Subscapularis Ventral scapula (subscapular fossa) Humerus (LT) Internally rotating arm Providing anterior stability Upper and lower subscapular nerves Supraspinatus Superior scapula (supraspinatus fossa) Humerus (greater tuberosity) Abducting Providing stability Externally rotating arm Suprascapular nerve Infraspinatus Dorsal scapula (infraspinatus fossa) Providing stability Externally rotating arm Teres minor Scapula (dorsolateral) Axillary nerve Levator scapulae Latissimus dorsi Trapezius Rhomboid minor
Axillary artery?Divided by pectoralis minor into 3 parts Mnemonic for branches “Screw The Lawyer, Save A Patient” Part Branch Course I Sup. Thoracic a. Medial to serratus anterior and pectoral muscles II Thoracoacromial a. Four branches: deltoid, acromial, pectoralis, clavicular Lateral thoracic a. Descends to serratus anterior III Subscapular a. (largest br.) Two branches: thoracodorsal and circumflex scapular (triangular space) Anterior humeral circumflex a. Blood supply to humeral head: arcuate artery lateral to bicipital groove Posterior humeral circumflex a. Branch in the quadrangular space accompanying the axillary nerve Profunda brachii artery (triangular interval) Thoracodorsal artery Teres major Circumflex scapular branch (triangular space) Latissimus dorsi Anterior circumflex humeral artery Subscapular artery Subscapularis Superior thoracic artery Subclavius Pectoralis minor Posterior circumflex humeral artery (quadrangular space)
Structures attached to the coracoid process?• Ligaments o Coracoclavicular (trapezoid, conoid) o Coracoacromial o Coracohumeral • Muscles o Pectoralis minor (insertion) o Coracobrachialis (origin) o Short head of biceps (origin)
Muscles inserted in bicipital groove?‘PLT sandwich’ or ‘Lady between 2 majors’ • Teres major (medial lip) • Latissimus dorsi (floor) • Pectoralis major (lateral lip) Tendon of long head of biceps lies in the groove
Shoulder joint abduction?• Supraspinatus (0-15ᵒ) • Deltoid (middle fibres) (15-90ᵒ) • Trapezius and serratus anterior (over 90ᵒ): which will require upward rotation of the scapula with lateral rotation of the humerus
Factors decreasing the stability of the shoulder joint?• Shallow glenoid cavity • Lax capsule with few ligaments • Inferior aspect is not supported due to the presence of quadrangular space
The main stabilizer of the shoulder joint?Rotator cuff muscles
Quadrangular space?See before The shoulder is stabilized by both static and dynamic restraints. • Static restraints Structures that provide unidirectional limitations to translation o Glenoid labrum o Articular version o Articular conformity o Negative intraarticular pressure o Capsule (posterior capsule and rotator interval) o Glenohumeral ligaments • Dynamic restraints These include joint concavity compression produced by synchronized contraction of the rotator cuff, acting to stabilize the humeral head within the glenoid; increased capsular tension produced by direct attachments of the rotator cuff to the capsule; the scapular stabilizers that act to maintain a stable glenoid platform (“ball on a seal’s nose”); and proprioception. N.B Synovial Joints These are freely moving joints in which the articulating bony surfaces are covered in smooth (hyaline) articular cartilage and separated by a film of viscous synovial fluid that serves as a lubricant (Fig. 5.31). Joint stability is provided by a fibrous capsule (which usually has intrinsic ligamentous thickenings), and often by internal or external accessory ligaments. Synovial fluid, which also aids metabolite transport to cells in the articular cartilages, is synthesized by the synovial membrane that lines the joint capsule.
Motor supply?• Deltoid • Teres minor
Sensory supply?• Skin to the lower half of deltoid (badge area)
Injury?• Inability to abduct the shoulder over 15ᵒ • Loss of sensation over the badge area
Upper limb reflexes?• Biceps reflex (C5/6) – located in the antecubital fossa, tap your finger overlying the biceps tendon • Triceps reflex (C7) – place forearm rested at 90º flexion • Supinator reflex (C6) – located 4 inches proximal to base of the thumb
Upper limb dermatomes?Myotomes Findings in nerve root compression Root Sensory Deficit Muscle Weakness Reflex Changes C4 • Lateral neck • Shoulder • Scapula • None C5 • Upper lateral arm and elbow • Deltoid • Biceps (variable) • Biceps C6 • Lateral forearm • Thumb and index finger • Biceps • Wrist extensors • Brachioradialis C7 • Middle finger • Triceps • Wrist flexors • Long finger extensors • Triceps C8 • Little and ring finger • Ulnar border of palm • Medial forearm • Finger flexors • None T1 • Medial arm • Dorsal interossei • Abductor digiti minimi • None Elbow flexors/Biceps C5 Wrist extensors C6 Elbow extensors/Triceps C7 Long finger flexors C8 Small finger abductors T1 1, 2 Buckle my shoe (Ankle). 3, 4 Kick the door (Knee).
Articulate humerus, radius and ulna?• Capitulum of the humerus + radial head • Trochlea of the humerus + trochlear notch of the ulna • Olecranon of the ulna+ olecranon fossa of the humerus
Clinical picture of radial nerve injury at the spiral groove?• Paralysis of wrist extensors → wrist drop • Paralysis of finger extensors → finger drop • Loss of sensation in the 1st web space
Identify x-ray?Supracondylar fracture of the humerus
Associated injuries?• Brachial artery injury (absent distal pulse) • Anterior interosseus nerve injury (unable to flex the interphalangeal joint of his thumb and the distal interphalangeal joint of his index finger) • Ulnar nerve injury (claw hand) • Radial nerve injury (wrist drop and finger drop)
Biceps and Triceps?Muscle Origin Insertion Action Innervation Coracobrachialis Coracoid Mid-humerus (medial) Flexion, adduction Musculocutaneous Biceps brachii Coracoid (short head) Supraglenoid (long head) Radial tuberosity Relations to bicipital tendon: Medially: Median n. and brachial a. Lateral: Radial nerve Supination, flexion Musculocutaneous Brachialis Anterior humerus Ulnar tuberosity (anterior) Flexing forearm Musculocutaneous, Radial Triceps brachii Infraglenoid (long head) Posterior humerus (lateral head) Posterior humerus (medial head)* Olecranon Extending forearm (Elbow extension). The long head can adduct the humerus and extend it from a flexed position Radial Blood supply by Profunda brachii artery * The radial nerve and profunda brachii vessels lie between the lateral and medial heads
Median nerve sensory distribution in the hand?• Lateral ⅔ of the palm of the hand • Lateral (radial) 3½ digits on the palmar side • Dorsum of the tips of index, middle and thumb
Median nerve motor distribution in hand?LOAF muscles • Lateral 2 lumbricals • Opponens pollicis • Abductor pollicis brevis • Flexor pollicis brevis
Clinical picture of median nerve injury at elbow?Ape-like hand • Hyperextended thumb (paralysis of FPB) • Adducted thumb (paralysis of abductor pollicis brevis) • Flat thenar eminence • Loss of sensations from: o Lateral ⅔ of the palm of the hand o Lateral 3½ digits (palmar and distal dorsal aspect)
Clinical picture of ulnar nerve injury at wrist?Claw hand • Clawing of the 4th and 5th digits (paralysis of the medial lumbricals and interossei) • Loss of sensation of the medial ⅓ of the palmar and dorsal aspects of hand and fingers
Cause of ulnar paradox?In proximal ulnar nerve injuries, there will be paralysis of the medial ½ of the FDP which will decrease flexion of the IP joints
How to test peripheral nerve motor function in the hand?
Superficial palmar arch?Formed mainly by the arch of the superficial division of the ulnar artery and is completed by the superficial palmar branch of the radial artery
Navicular (Scaphoid) bone blood supply?It receives its blood supply primarily from lateral and distal branches of the radial artery, via palmar and dorsal branches. These provide an "abundant" supply to middle and distal bone, but neglects the proximal portion, which relies on retrograde flow
How to test ulnar artery (Allen' s test)?• Elevate the hand and ask the patient to make a fist for 30 sec. • Apply pressure on both ulnar and radial aa. To occlude both • While still elevated, open the hand, it should be blanched • Release pressure over the ulnar artery, colour should return in 7 seconds
Identify styloid process of the radius?
Identify Lister’s tubercle?
Clinical application?Tubercle on dorsal radius. “Lighthouse of the wrist.” EPL tendon runs around it. (It serves as a pulley for the tendon of the EPL (Extensor pollicis longus), which wraps around the medial side and takes a 45 degree turn) Demonstration of Allen’s test: Occluding the radial and ulnar arteries Demonstration of Allen’s test: Maintaining occlusion as patient repeatedly clenches the fist Demonstration of Allen’s test: Release the radial artery and watch for reperfusion Demonstration of Allen’s test: Repeat the first two steps then release the ulnar artery and watch for reperfusion
Attachment of flexor retinaculum?• Proximal o Pisiform o Tubercle of scaphoid • Distal o Hook of hamate o Trapezium
Structures passing through carpal tunnel?• 4 tendons of flexor digitorum superficialis • 4 tendons of flexor digitorum profundus • 1 tendon of flexor pollicis longus • 1 tendon of flexor carpi radialis • Median nerve.
Movements of the thumb?Movement Muscles Innervation Flexion at MCP/IPJ Flexor pollicis longus Flexor pollicis brevis Median (anterior interosseous n.) Median (recurrent branch) Extension at MCP/IPJ Extensor pollicis longus Extensor pollicis brevis Radial (PIN) Flexion (flexion/transpalmar adduction) Flexor pollicis brevis Adductor pollicis Median (recurrent branch) Ulnar (deep branch) Extension (radial abduction) Abductor pollicis longus Extensor pollicis brevis Radial (PIN) Abduction (palmar) Abductor pollicis longus Abductor pollicis brevis Radial (PIN) Median (recurrent branch) Adduction (ulnar adduction) Adductor pollicis Ulnar (deep branch) Opposition Opponens pollicis Flexor pollicis brevis Abductor pollicis brevis Median recurrent branch Extensor indicis tendon Palmaris longus tendon Flexor retinaculum Median nerve Flexor carpi radialis tendon
How to test FDP?By fixing the PIP
How to test FDS?Adjacent digits must be held in extension, in order to eliminate FDP motion in adjacent fingers, which otherwise might give the impression of FDS motion in the examined finger
Where do the tendons of FDS and FDP insert?FDS: Split tendon on both sides of the middle phalanx FDP: Passes through the split tendon of FDS to be inserted into the terminal phalanx
Tendon attached to pisiform?Flexor carpi ulnaris
What makes extensor tendons attached to the phalanges?Extensor expansion
What is the function of intertendinous connections?• Create space between extensor tendons • Redistribute force between tendons • Coordinate extension of fingers • Stabilize MCP joint
Identify Extensor Digitorum?Insertion? Extensor expansion of middle and distal phalanges of the 2nd, 3rd, 4th, and 5th fingers Assessing the flexor digitorum superficialis. Assessing the flexor digitorum profundus.
Identify?
First dorsal interosseous?Origin: From the first metacarpal Insertion: Into the lateral side of extensor expansion of the index finger Action: Abduction of index finger N. Supply: Deep branch of the ulnar nerve
When you are doing power grip of the hand, what is the role of radial nerve?Radial nerve supplies wrist extensors which give mechanical advantage to power grip by synergistic activity which cause more efficient flexion of the digits
Why hand grip is powerful in extension than flexion?Because the flexor muscles in extension position is in a state of tension than in flexion position, so contraction in this position is more powerful Mnemonic “PAD & DAB” • Palmar interossei ADduct • Dorsal interossei ABduct
Identify the two tendons inserting into the index finger?• Extensor indicis (medial) • Extensor digitorum (lateral)
Boundaries?Posterior border (medially) Extensor pollicis longus tendon Anterior border (laterally) Extensor pollicis brevis tendon Abductor pollicis longus tendon Proximal border Styloid process of the radius Distal border Apex of snuffbox triangle Floor Trapezium and scaphoid Content Radial artery
What does tenderness of the scaphoid mean?Possible fracture of the scaphoid bone. Blood supply of scaphoid? See before
Insertion of EPL?Dorsum of the base of the terminal phalanx of the thumb
Insertion of EPB?Dorsum of the base of the proximal phalanx of the thumb
Surface markings / Show me anatomical snuff box on your hand?Anatomical snuffbox Extensor pollicis longus tendon
Where else does the gluteus maximus muscle insert?Onto the gluteal tuberosity of the femur
What is the nerve supply and nerve roots of gluteus maximus?Gluteus maximus is supplied by the inferior gluteal nerve (L5, S1, S2)
What are the actions of gluteus maximus?Gluteus maximus performs external rotation and extension of the hip
What nerve supplies tensor fasciae lata?The superior gluteal nerve supplies tensor fascia lata.
Where does the gluteus medius muscle insert?Onto the lateral surface of the greater trochanter. Gluteus minimus also inserts onto the greater trochanter deep to gluteus medius.
What is the action of gluteus medius?During standing, it is a hip abductor. During gait, gluteus medius, together with gluteus minimus, support the body whilst one leg is in the air, preventing the pelvis from dropping to the opposite side
What clinical sign is evident with weakness of gluteus medius and minimus / How to test?A Trendelenburg gait or a positive Trendelenburg test
Damage to what nerve can produce this distinctive gait?Damage to the superior gluteal nerve Causes of Trendelenburg gait • Weak abductor muscles • Avulsion of the abductor muscle tendon • L5 radiculopathy • Superior gluteal nerve injury • Myopathy • Neurological conditions such as stroke and multiple sclerosis • Trauma / fractures of the pelvis and hip • DDH, congenital coxa vara or coxa valga • Painful hip • Unequal leg length • Wide walking base
Quadratus femoris origin, insertion, nerve supply and action?Muscle Origin Insertion Nerve Segment External Rotators Gluteus maximus Ilium, posterior gluteal line Iliotibial band Gluteal sling (femur) Inferior gluteal L5-S2 (P) Piriformis Anterior sacrum/sciatic notch Proximal greater trochanter Piriformis S2 (P) Obturator externus Ischiopubic rami/obturator Trochanteric fossa Obturator L2-L4 (A) Obturator internus Ischiopubic rami/obturator membrane Medial greater trochanter Obturator internus L5-S2 (A) Superior gemellus Outer ischial spine Medial greater trochanter Obturator internus L5-S2 (A) Inferior gemellus Ischial tuberosity Medial greater trochanter Quadratus femoris L5-S1 (A) Quadratus femoris* Lateral border of the upper part of the Ischial tuberosity Quadrate line of femur Quadratus femoris L5-S1 (A) Abductors Gluteus medius Ilium between posterior and anterior gluteal lines Greater trochanter Superior gluteal L4-S1 (P) Gluteus minimus Ilium between anterior and inferior gluteal lines Anterior border of
Where does the iliotibial tract attach?The Iliotibial tract is attached to the anterolateral iliac tubercle of the iliac crest proximally and the lateral condyle of the tibia distally.
What muscles insert onto it?• Gluteus maximus • Tensor fasciae lata
What is its clinical significance?• The iliotibial tract stabilizes the knee in extension and in partial flexion. It is important in walking and running • During standing: pelvic stabilisation & posture control especially during asymmetrical standing by performing knee hyperextension & locking & converting the limb into a rigid supportive pillar • Hip flexion, extension, abduction, lateral rotation, medial rotation (through the actions of gluteus maximus and tensor fasciae latae). Attachment of deep fibers to gluteal tuberosity Tubercle of crest of ilium Gluteus minimus Deep fascia of leg
What are the surface markings of the sciatic nerve?The sciatic nerve (L4,5, S1,2,3) exits the pelvis via the greater sciatic foramen from below the piriformis muscle. The surface marking of the sciatic nerve is a curved line drawn from 2 points: halfway between the posterior superior iliac spine to the ischial tuberosity to halfway between the ischial tuberosity and the greater trochanter.
Which vessels exit the greater sciatic foramen from above?The superior gluteal vessels and nerve exit above piriformis.
What variations do you know with regard to the sciatic nerve exiting the pelvis?In the majority of cases the sciatic nerve exits beneath the piriformis. Alternatively, either the whole nerve may pass through piriformis, or it may divide high with one division passing through or around the piriformis Identify arteries Highest point on iliac crest Ischial tuberosity Greater trochanter Gluteal fold A. Common femoral artery B. Lateral circumflex femoral artery C. Superficial femoral artery D. Profunda femoris artery
What muscles attach to the lesser trochanter of the femur?• Psoas major • Iliacus
Where does the psoas major originate?The deep part of psoas major originates from the transverse processes of L1-L4. The superficial part originates from the lateral surfaces of T12-L4 and the intervening vertebral discs.
What is the action of psoas major?Psoas major flexes and externally rotates the hip
Describe the blood supply to the head of the femur?The majority of the blood supply to the head of the femur is from retinacular arteries, which arise as ascending cervical branches from the extracapsular arterial anastomosis. This is formed posteriorly by the medial femoral circumflex artery and anteriorly from branches of the lateral femoral circumflex artery with minor contributions from the superior and inferior gluteal arteries. There is also supply from the artery of the ligamentum teres, also known as the artery of the round ligament of the femoral head (a branch of the obturator artery).
Where do these arteries originate?The medial and lateral circumflex femoral arteries originate from the profunda femoris The artery of the ligamentum teres originates from the obturator artery
Identify origin and insertion of quadriceps muscle on the skeleton?
Hamstrings?Muscle Origin Insertion Innervation Muscles of the Posterior Thigh Biceps femoris (long head) Medial ischial tuberosity Fibular head/lateral tibia Tibial Biceps (short head) Lateral linea aspera/lateral intermuscular septum Lateral tibial condyle Peroneal Semitendinosus Distal medial ischial tuberosity Anterior tibial crest Tibial Semimembranosus Proximal lateral ischial tuberosity Oblique popliteal ligament Posterior capsule Posterior/medial tibia Popliteus Medial meniscus Tibial Actions of the hamstring muscles All three muscles: Flexion of the leg at the knee joint. Extension of thigh at the hip. Biceps Lateral rotation of the hip and knee Semitendinosus and Semimembranosus Medially rotates the thigh at the hip joint and the leg at the knee joint. Knee flexors • Hamstrings (biceps, semitT, semiM) • Sartorius • Popliteus • Gracilis • Gastroc Structures at risk in supracondylar fracture of the femur
Differential diagnosis of lump from popliteal fossa?• Backer's cyst • Popliteal artery aneurysm • Lipoma • Schwannoma • Popliteal vein varicosities Posterior cutaneous nerve of thigh Biceps femoris muscle (short head) Femoral vein Semimembranosus muscle Popliteal fossa Plantaris muscle Common fibular nerve Tibial nerve Popliteal artery Popliteal vein Small saphenous vein Posterior cutaneous nerve of thigh Small saphenous vein Popliteus muscle Adductor hiatus Supracondylar fracture of femur
Hesselbach Triangle?See Abdominal Anatomy
Inguinal ligament?See Abdominal Anatomy
Superficial and deep rings?See Abdominal Anatomy
Structures passing through inguinal canal?See Abdominal Anatomy
Ilioinguinal and iliohypogastric nerve injuries?See Abdominal Anatomy
Vascular lacuna?It’s the compartment beneath the inguinal ligament which allows for passage of the femoral vessels, lymph vessels and lymph nodes. The muscular lacuna is the lateral compartment of the thigh inferior to the inguinal ligament, it is separated by the iliopectineal arch from the vascular lacuna Lacuna vasorum (vascular lacuna) is medially, while lacuna musculorum (muscular lacuna) is laterally.
Contents of lacuna vasorum?(order from medial part) • Deep inguinal lymph nodes • Femoral vein, • Femoral artery • Femoral branch of the genitofemoral nerve
Contents of lacuna musculorum?• Femoral nerve • Iliopsoas • Lateral femoral cutaneous nerve Femoral n. injury symptoms Motor • Weak hip flexion (iliacus, psoas and sartorius) • Inability to extend the knee (quads) Sensory • Anterior and medial aspect of thigh (intermediate and lateral cutaneous n. of the thigh) • Medial side of leg (saphenous)
Meralgia paresthetica?Tingling, numbness, and burning pain in the outer side of the thigh. The disorder occurs when the lateral femoral cutaneous nerve is compressed or squeezed as it exits the pelvis.
What is Hunter's canal?Hunter's canal, also known as the subsartorial or adductor canal, runs from the apex of the femoral triangle to the popliteal fossa.
What are the boundaries of Hunter's canal?Borders Laterally Vastus medialis muscle Posteriorly Adductor longus, adductor magnus Roof Sartorius
What are the contents of Hunter's canal?
What is the surface marking of the adductor hiatus?The adductor hiatus lies ⅔ along the line between the ASIS and the adductor tubercle of the femur.
What are the surface markings of the femoral artery?The femoral artery can be palpated at the mid-inguinal point, which lies halfway between the pubic symphysis and the ASIS Contents Saphenous nerve Superficial femoral artery Superficial femoral vein (posterior to the artery in the upper part then posterolateral) Nerve to vastus medialis The inguinal region and femoral triangle 1)anterior superior iliac spine; 2)lateral femoral cutaneous nerve and its zone of emergence into femoral triangle (white): range 0.3–7.3 cm (mean 2.1–3.5 cm) from anterior superior iliac spine; 3)inguinal ligament; 4)femoral artery and zone of emergence into femoral triangle (white): mid-inguinal point ± 1 cm either side, femoral nerve (yellow cross) and vein (blue cross) sit lateral and medial, respectively, to the femoral artery; 5)femoral head: located 2–4 cm above the midpoint of the greater trochanter to pubic tubercle line; 6)pubic tubercle; 7)greater trochanter to pubic tubercle line; 8)profunda femoris artery: almost always arises 6.5 ± 1.5 cm distal to the mid-inguinal point, or superior to or at the level of the inguinal/groin crease; 9)zone of saphenofemoral junction location: almost always sits within a 3 cm × 3 cm zone situated 1–4 cm lateral and 0–3 cm inferior to the pubic tubercle; 10)sartorius; 11)inguinal/groin crease;
What nerve supplies the muscles in the posterior compartment of the leg?The tibial nerve supplies the posterior compartments of the leg (deep and superficial) • Superficial (GPS): Gastrocnemius, soleus and plantaris • Deep (Pfft): Popliteus, flexor hallucis longus, flexor digitorum longus, tibialis posterior
How many compartments are there in the leg and what structures are in each compartment?Separated by the interosseous membrane (anterior and posterior compartments), anterior fascial septum (separate anterior and lateral compartments) and posterior fascial septum (separate lateral and posterior compartments) Compartment Nerve Muscles Blood supply Anterior compartment Deep peroneal nerve • Tibialis anterior • Extensor digitorum longus • Extensor hallucis longus • Peroneus tertius Anterior tibial artery Superficial Posterior compartment Tibial “GPS” • Gastrocnemius • Soleus • Plantaris Posterior tibial Deep Posterior compartment “Pfft…” • Popliteus • Flexor hallucis longus • Flexor digitalis longus • Tibialis posterior Lateral compartment Superficial peroneal • Peroneus longus • Peroneus brevis Peroneal artery
What nerve supplies the anterior compartment of the leg?The deep peroneal nerve (anterior tibial nerve)
Demonstrate on the subject the actions of tibialis anterior, tibialis posterior, peroneus longus, brevis, gastrocnemius, soleus?Tibialis anterior: Dorsiflexion and inversion Tibialis posterior: Plantarflexion and inversion Peroneus longus: Eversion and abduction Peroneus brevis: Eversion GPS: Plantar flexion
How would you recognize compartment syndrome in the lower leg?Compartment syndrome is an emergency that presents with pain out of proportion to the injury sustained, in someone with a swollen leg, particularly acute on passive stretching of the ankle. There may be paresthesia, pulselessness and paralysis, all late signs and suggestive of impending limb necrosis.
Tibial nerve injury symptoms?Loss of sensation over the planter surface of the foot. Loss of toe flexion, ankle inversion. Shuffling gait. Loss of the lateral longitudinal arch of the foot, and atrophy of the intrinsic foot muscles eventually results in claw foot.
Orientate and articulate the tibia and fibula?
What are the components of the Medial/Lateral longitudinal and Transvers arches?Arch Medial longitudinal arch Lateral longitudinal arch Transverse arch Construction • Calcaneus, Talus, Navicular • 3 cuneiform • 3 medial metatarsals • Calcaneus • Cuboid • 2 lateral metatarsal • Cuboid, 3 cuneiform • Bases of metatarsals Function High arch concerned with the elastic propulsion of the foot during walking Low arch concerned mainly with body weight transmission Elastic propulsion of foot and body weight transmission Factors maintaining Ligaments • Interosseus ligaments • Plantar aponeurosis • Long planter ligament • Deltoid and spring ligaments Muscles • Tibialis anterior & posterior • Short muscles of the big toe • FHL Ligaments • Interosseus ligaments • Plantar aponeurosis
Identify bones of the foot?
Identify ligaments on the medial and lateral aspects of the ankle?Ligament Origin Insertion Capsule Tibia Talus Deltoid (4 parts) Anterior tibiotalar Anterior colliculus of medial malleolus Anteromedial surface of talus Tibionavicular Navicular tuberosity Tibiocalcaneal Sustentaculum tali Posterior tibiotalar (deep) Post. colliculus of medial malleolus Medial talus & medial tubercle LCL (3 parts) Anterior talofibular Lateral malleolus Transversely to talus anteriorly Posterior talofibular Lateral malleolus Transversely to talus posteriorly Calcaneofibular Lateral malleolus Obliquely to calcaneus posteriorly
Attachments of deltoid ligament?Superior: • Medial malleolus Inferior: • Tuberosity of the navicular • Spring ligament • Neck of talus • Sustentaculum tali • Body of talus Lateral collateral ligament (LCL) • Anterior talofibular • Posterior talofibular • Calcaneofibular Syndesmotic complex • Anterior tibiofibular • Posterior tibiofibular • Inferior transverse tibiofibular (deep fibers of posterior tibiofibular)
Midtarsal joint (of “Chopart”)?The transverse tarsal joint or midtarsal joint or Chopart’s joint is formed by the • Articulation of the calcaneus with the cuboid (calcaneocuboid joint) (saddle) • Articulation of the talus with the navicular (talocalcaneonavicular joint) (ball & socket)
What movements occur at the subtalar (talocalcaneal) joint?Inversion and eversion of the foot occur at the subtalar joint.
Which muscles perform these actions?Inversion: Tibialis anterior and posterior (with some help from the extensor and flexor hallucis longus muscles) Eversion: Peroneus longus and brevis
What is the type of the subtalar (talocalcaneal) joint?Synovial plane joint
What is the type of the ankle (talocrural) joint?Synovial hinge joint
What are the bones forming ankle joint?Trochlear surface of talus, lower end of tibia and fibula
Ankle joint is most stable in dorsiflexion why?Dorsiflexion is more stable than plantarflexion. The talus is stabilized due to the wider anterior side of the trochlea being immobilized by the tibial articulation. In plantarflexion, the narrower posterior side is articulating more and so more movement is possible since it does not completely fill the space allowed the anterior side.
What is the type of inferior tibiofibular joint?Syndesmosis
Associated injury in syndesmotic fracture?Fractures lateral malleolus Point to the Achilles tendon
What muscles make this up?Three muscles insert into the Achilles or calcaneal tendon: • Soleus • Gastrocnemius • Plantaris
Structures passing behind the medial malleolus?Structures posterior to the medial malleolus: Deep to flexor retinaculum (Posteromedially) Tom Does Very Nice Hats • Tibialis posterior tendon • Flexor Digitorum longus • posterior tibial Vessels • posterior tibial Nerve • Hallucis longus Structures deep to extensor retinaculum (Anterior): Tom Has Very Nice Dogs & Pigs • Tibialis anterior • Extensor Hallucis longus • Anterior tibial Vessels • Anterior tibial Nerve • Extensor Digitorum longus • Peroneus tertius
Arteries of the foot?Dorsalis pedis artery • It is the continuation of the anterior tibial artery and begins as the anterior tibial artery crosses the ankle joint. • It passes anteriorly over the dorsal aspect of the talus, navicular, and intermediated cuneiform bones, and then passes inferiorly, as the deep planter artery, between the two heads of the first dorsal interosseous muscle to join the deep planter arch in the sole of the foot. Medial and lateral plantar arteries • Arteries which supply the sole of the foot • Branches of posterior tibial artery • Run in the sole between the 1st and 2nd layer of muscles • Lateral plantar artery forms plantar arch along with dorsalis pedis artery
Where to palpate dorsalis pedis and posterior tibial arteries?• Lateral to the EHL tendon • Halfway between the posterior border of the medial malleolus and achilles tendon
Demonstrate the foot pulses on this actor?The dorsalis pedis pulse is found between the first two metatarsal bones The posterior tibial pulse is found 2-3cm below and behind the medial malleolus
Identify tendons on the dorsum of the foot?
Surface markings of EHL?
What movements does extensor hallucis longus perform?It extends the big toe, dorsiflexes the foot and assists with inversion of the foot.
What vessels would you find deep to extensor hallucis longus?The anterior tibial artery and vein
And what nerve that lies deep to it?The deep peroneal nerve Where would you test sensation of… S1? S1 is tested on the lateral aspect of the foot L4? L4 is tested over the medial malleolus
Deep peroneal nerve?The deep peroneal nerve is tested at the first web interspace
Superficial peroneal nerve?The superficial peroneal nerve is tested over the dorsum of the foot, other than the first web interspace
Sural Nerve?The sural nerve is tested over the lateral malleolus
On an actor demonstrate how you would test the knee and ankle reflexes?Knee reflex: The foot should be unsupported, relaxed and off the ground. The thigh should be fully exposed. Test by tapping the patellar tendon with a tendon hammer. You are looking for reflex contraction of the quadriceps muscles. Ankle reflex: The foot should be pointing laterally, be flexed, and relaxed. the leg should be fully exposed. Test by tapping the Achilles tendon with a tendon hammer. You are looking for reflex contraction of the calf muscles.
What nerve roots do these reflexes originate from?Ankle: S1 Knee: L3/4
What movement is ankle dorsiflexion?Dorsiflexion is the upwards movement of the foot in relation to the leg
At which joint does dorsiflexion occur?At the ankle joint between the tibia/fibula and the talus
What muscles are involved in dorsiflexion?Muscles of the anterior compartment of leg are involved: • Tibialis anterior • Extensor hallucis longus • Extensor digitorum longus • Peroneus tertius
How would you demonstrate ankle plantarflexion?Plantarflexion is the downwards movement of the foot in relation to the leg.
What muscles are involved?Both the superficial and deep posterior compartments of the leg are involved Superficial posterior compartment: • Gastrocnemius • Soleus • Plantaris (only weak participation) Deep posterior compartment: • Flexor hallucis longus • Flexor digitorum longus • Tibialis posterior • Popliteus
What action occurs when tibialis anterior and tibialis posterior contract together?Ankle inversion
At which joint does this occur?Inversion and eversion both occur at the subtalar joint
What muscles are responsible for ankle eversion?Peroneus brevis and peroneus longus
Which nerve innervates them?The superficial peroneal nerve
What motor and sensory function is lost with damage to the superficial peroneal nerve?Inability to evert the foot and loss of sensation over the dorsum of the foot, apart from the first web space, which is innervated by the deep peroneal nerve
Anterior relations?• Celiac trunk and branches • Body of the pancreas • SMA • 3rd part of duodenum • Root of mesentery • Splenic vein • Left renal vein
Surface markings of transpyloric plane?Located halfway between the jugular notch and the upper border of the pubic symphysis Types of Aneurysms
Identify branches on mesenteric angiogram?A. Abdominal aorta B. Rt. common iliac C. Lt. Common iliac D. Lt. Renal a. E. Rt. renal a. F. splenic a. G. common hepatic H. SMA I. gastroduodenal a J. Lt. Hepatic a. K. Rt. hepatic a. L. IMA
Identify branches supplying GIT?
IVC Tributaries?Level Vein T8 Hepatic vein Inferior phrenic vein Pierces diaphragm L1 Suprarenal veins Renal vein L2 Gonadal vein L1-5 Lumbar veins L5 Common iliac vein Formation of IVC I Like To Rise So High” • Iliacs • Lumbar • Testicular • Renal • Suprarenal • Hepatic veins
Identify right and left gonadal veins?
Anterior relations of renal veins?• Rt. side: o 2nd part of duodenum • Lt. side o Body of Pancreas o SMA o Splenic vein
What are the first 2 organs injured in stab epigastrium?• Liver (left lobe) • Stomach
What demarcates left and right lobe?Anatomical: • Falciform ligament (anteriorly) • Fissure for ligamentum teres and ligamentum venosum (posteroinferiorly) Surgical: • A line passing from IVC to the fossa of GB
Venous drainage?Hepatic veins to IVC
What artery of the celiac trunk supplies both liver and stomach?Hepatic artery (runs in the free border of lesser omentum to porta hepatis)
Porta hepatis structures?From anterior to posterior • Right and left hepatic ducts • Hepatic artery • Portal vein
Ligaments supporting?• Falciform ligament (to the diaphragm and AAW) • Lesser omentum (to the stomach and 1st part of duodenum) • Right and left triangular ligament (to the diaphragm) • Upper and lower coronary ligament (to the diaphragm) How to differentiate between Rt and Lt lobes • Falciform ligament • Bare area on the R (no peritoneum) • IVC Gallbladder Surface marking of Gallbladder At the angle between the 9th costal cartilage and the lateral margin of the rectus sheath
Why is there shoulder pain in cholecystitis?An inflamed gallbladder may irritate the diaphragm. Roots of phrenic nerve that supply the diaphragm as the same as the supraclavicular nerve supplying the shoulder tip. Hepatic duct Quadrate lobe Fissure for ligamentum teres Left lobe Hepatic artery Fissure for ligamentum venosum Caudate lobe Portal vein Bile duct Cystic duct Porta hepatis Right lobe Fundus of GB Body of GB Neck of GB
Parts?Head, Neck, Body, and Tail
Production of islet cells?• Alpha cells: glucagon • Beta cells: insulin • D cells: somatostatins
Ducts / Describe ductal drainage system of pancreas / Where do the pancreatic duct open?• Main pancreatic duct (of Wirsung): drains head, body and tail → opens into major duodenal papilla. • Accessory pancreatic duct (of Santorini): drains the uncinate process → opens into minor duodenal papilla.
Blood supply?3 sources 1. Superior pancreaticoduodenal aa (from gastroduodenal artery) 2. Inferior pancreaticoduodenal aa (from SMA) 3. Pancreatic branches (from splenic artery)
Vessels encountered during Whipple?• Abdominal aorta • SMA and SMV • PV • Left renal vein • Splenic vein • Superior and inferior pancreaticoduodenal arteries
Ligament connecting the tail of pancreas with the spleen?Lienorenal (splenorenal) ligament
Peritoneal relation of pancreas?All is retroperitoneal except for the tail
Vessel present behind body of pancreas?Splenic artery (above) and splenic vein
Vessel present behind neck?Portal vein
Space present behind pancreas?Lesser sac
Development of pancreas?• Ventral bud: From the hepatic diverticulum and it gives rise to the lower part of the head and uncinate process. • Dorsal bud: From the dorsal aspect of the duodenum and gives rise to upper part of the head, neck, body and tail.
Structure to warry during splenectomy?Tail of the pancreas
Describe the course of splenic arteries?Arises from the coeliac trunk → passes to the left above the upper border of the pancreas → behind the stomach separated from it by the lesser sac → lien ligament → ends by giving up terminal branches inside the hilum of the spleen It supplies: pancreas, stomach, spleen 1,3,5,7,9,11 (odd numbers up to 11) 1 inch thick, 3 inches wide, 5 inches long, weighs 7oz (150-200g), lies between the 9th and 11th ribs
Begins?At the lower border of cricoid cartilage(c6)
Blood supply?Artery Vein Lymphatics Muscularis externa Upper third Inferior thyroid Inferior thyroid Deep cervical Striated muscle Mid third Aortic branches Azygos branches Mediastinal Smooth & striated muscle Lower third Left gastric Left gastric Gastric Smooth muscle
Cell lining?Stratified squamous epithelium
Barret's esophagus?Columnar metaplasia with increased risk of developing adenocarcinoma
Achalasia?Esophageal achalasia is an esophageal motility disorder involving the smooth muscle layer of the esophagus and the lower esophageal sphincter (LES). It is characterized by incomplete LES relaxation, increased LES tone, and lack of peristalsis of the esophagus
Microscopic picture of achalasia?Hypertrophied musculature with absence of myenteric plexus
Lymphatic drainage?See table
What makes an indent on the esophagus?• Left bronchus • Aortic arch • Left atrium
Complications of perforated esophagus?Mediastinitis Constrictions of the esophagus Structure Distance from incisors Cricoid cartilage 15cm Arch of the Aorta 22.5cm Left principal bronchus 27cm Diaphragmatic hiatus 40cm
Parts?• Fundus • Body • Pylorus
Blood supply?Arterial Venous • Left gastric artery from celiac trunk • Right gastric artery from hepatic artery • Left gastroepiploic from splenic artery • Short gastric a. from splenic artery • Right gastroepiploic from gastroduodenal from hepatic artery • Left gastric vein → portal vein • Right gastric vein → portal vein • Left gastroepiploic → splenic vein • Short gastric veins → splenic vein • Right gastroepiploic vein → SMV
Peritoneal relations / Which part of the duodenum lies intraperitoneal?The first part of the duodenum lies within the peritoneum, but its other parts are retroperitoneal
Blood supply?• Superior pancreaticoduodenal artery (from gastroduodenal) • Inferior pancreaticoduodenal artery (from SMA) • Branches from hepatic, right gastric, right gastroepiploic and supraduodenal arteries
Relations of the different parts of the duodenum?First part: • Superiorly: Epiploic foramen being divided from it by the portal vein and bile duct. • Inferiorly: Head and neck of the pancreas. • Anteriorly: Quadrate lobe of the liver and gallbladder. • Posteriorly: Portal vein, gastroduodenal artery, and common bile duct (CBD). Second part: • Anteriorly: Gallbladder and right lobe of the liver, transverse colon, transverse mesocolon (commencement), and coils of the small intestine. • Posteriorly: Right kidney and right renal vessels, right edge of the inferior vena cava (IVC), and right psoas major muscle. • Medially: Head of the pancreas. • Laterally: From below upward, ascending colon, right colic flexure, and right lobe of the liver. Third part: • Anteriorly: Root of the mesentery, superior mesenteric vessels, and coils of the jejunum. • Posteriorly: Right psoas major, right ureter, IVC, abdominal aorta, and right gonadal vessels. • Superiorly: Head of the pancreas with its uncinate process. • Inferiorly: Coils of the jejunum. Fourth part: • Anteriorly: Transverse colon and transverse mesocolon. • Posteriorly: Left psoas major muscle, left sympathetic chain, left gonadal vessels, and inferior mesenteric vein. • Superiorly: Body of the pancreas. • On to the left: Left kidney and left ureter. • On to the right: Upper part of the root of mesentery.
Vessels present in front and behind the 3rd part of the duodenum?
Major duodenal papilla (papilla of Vater)?It’s a well-marked conical projection on the posteromedial wall and situated 8-10 cm distal to the pylorus (2nd part of the duodenum). It’s the opening of the junction of pancreatic duct and common bile duct (ampulla of Vater) into the duodenum.
Blood supply?• Appendicular artery from the ileocolic artery • Appendicular vein to SMV
Why appendicitis pain is referred to umbilicus?Pain initially starts in the periumbilical region as visceral pain from the appendix is conveyed in nerve fibres entering the spinal cord at the T10 level (the T10 dermatome covers the level of the umbilicus). Irritation of the parietal peritoneum by an inflamed appendix later on causes localisation of pain to the RIF. Positions of the appendix Arterial supply to the cecum and appendix
Attachments?Origin Sternal part Xiphoid process of the sternum Costal part Inner surface of the lower six costal cartilages Vertebral part (crura and arcuate ligaments) • Right crus (L1, L2, L3) • Left crus (L1, L2) • Median arcuate ligament (between the 2 crura) • Medial arcuate ligament (extends from the side of the body of L1 to the tip of the transverse process of L2) • Lateral arcuate ligament (extends from the tip of the transverse process of L1 and is inserted into the lower border of the 12th rib) Insertion Central aponeurotic tendon Actions Inspiration and forced expiration Innervation Phrenic nerve (C3, C4, C5) – “3, 4, 5, keeps the diaphragm alive” Blood Supply Inferior Phrenic artery
Structures passing through inguinal canal?• Spermatic cord (male) / Round ligament (female) • Ilioinguinal nerve • Genital branch of the genitofemoral nerve
Inguinal ligament?The inguinal ligament also known as Poupart's ligament or groin ligament, is a band running from the pubic tubercle to the anterior superior iliac spine. The inguinal ligament connects the oblique muscles in the abdomen to the pelvis.
Deep and Superficial inguinal rings?• The deep (internal) ring is found above the midpoint of the inguinal ligament. which is lateral to the epigastric vessels. The ring is created by the transversalis fascia • The superficial (external) ring marks the end of the inguinal canal, and lies just superior to the pubic tubercle. It is a triangle shaped opening, formed by the evagination of the external oblique Anterior superior iliac spine Superficial inguinal ring Mid-inguinal point halfway between the pubic symphysis and the anterior superior iliac spine. The femoral pulse can be palpated here. Midpoint of the inguinal ligament halfway between the pubic tubercle and the anterior superior iliac spine (the two attachments of the inguinal ligament). The opening to the inguinal canal is located just above this point.
Hesselbach Triangle?The inguinal triangle (Hasselbach’s triangle) is a region in the anterior abdominal wall. Aka Medial inguinal fossa. Does not contain any structures of clinical importance, however it demarcates an area of potential weakness through which herniation of abdominal contents can occur. Boundaries • Medial: lateral border of rectus abdominis • Lateral: inferior epigastric vessels • Inferior inguinal ligament
Ilioinguinal and iliohypogastric nerve injuries?The ilioinguinal nerve arises from the anterior ramus of the L1 nerve root from the lumbar plexus along with the iliohypogastric nerve. Supply of Ilioinguinal nerve • Cutaneous innervation to the superior medial thigh • Anter ⅓ of scrotum + root of penis (male) / Anterior ⅓ of labium majus + root of clitoris (female) • Motor branch to internal oblique and transversus abdominis Supply of iliohypogastric nerve • Posterolateral gluteal skin (lateral cutaneous branch) • Lower abdominal skin over pubis (anterior cutaneious branch)
Identify internal iliac artery?
Blood supply?Arterial: Superior and inferior vesical arteries from the internal iliac artery Venous: To vesical venous plexus → internal iliac vein
Nerve supply to detrusor muscle?• Sympathetic: inhibit contraction of the muscle (from L1, L2) • Parasympathetic: stimulate contraction of the muscle (from S2-S4)
Most common bladder cancer?• TCC • SCC • Mixed • Adenocarcinoma
How does ureter enter the bladder?At the base of the bladder at the corner of the trigone
Peritoneal relations of the bladder?Covers the superior surface and the upper part of the posterior surface
Layers encountered during suprapubic catheterization?• Skin • Subcutaneus tissue • Scarpa's fascia • Linea alba • Fascia transversalis • Preperitoneal fat
Posterior relations of the bladder?Male • Rectovesical pouch • Two vas deferens • Terminal part of the 2 ureters Female • Vesicouterine pouch • Terminal part of the 2 ureters Bladder. A) Superolateral view. B) The trigone. Anterior view with the anterior part of the bladder cut away. Ligaments that anchor the neck of the bladder and pelvic part of the urethra to the pelvic bones. A) In women. B) In men.
During intra-abdominal operations, where to identify ureter?At the bifurcation of common iliac artery
How many cusps have the pulmonary valve?3
Vertebral level of the pulmonary valve?T6
Where to auscultate pulmonary valve?2nd ICS left parasternal edge
Tributaries of Azygos vein?“Right Handed PM Loves Eating Burgers” • Right superior intercostal vein • Hemiazygos and accessory hemiazygos • Pericardial veins • Mediastinal veins • Lower right posterior intercostal veins • Esophageal veins • Bronchial veins
Branches of ascending aorta?Right and left coronary arteries arising from the aortic sinus opposite the aortic valve
Identify structures passing through the hilum of lung?• Pulmonary artery and vein (most anterior) • Right and left main bronchus (most posterior) • Bronchial artery and vein • Lymph nodes • Autonomic nerves
Pulmonary ligament?Pleural fold that connects the mediastinal surface of the lung and the pericardium to allow expansion of pulmonary veins with increased blood flow Anterior border Posterior border Costal surface Inferior border (diaphragmatic surface) surface LEFT LUNG RIGHT LUNG vein
Identify surface anatomy of the lung on the skeleton?• Apex: curved line from the sternoclavicular joint to 3 cm above the junction between the medial ⅓ and the middle ⅓ of clavicle • Anterior border: Sternoclavicular joint to the xiphisternal joint behind the lateral border of the sternum (left lung deviates laterally from the sternum at the 4th costal cartilage to form the cardiac notch) • Inferior border: Line drawn between 6th rib MCL, 8th rib MAL, 10th rib vertebral column • Posterior border: Transverse process of C7 – T10 • Hilum: Opposite T5, T6, T7 • Carina: At the level of T4 Superior lobe Horizontal fissure Middle lobe Rib VI Inferior lobe Rib VII Rib X Parietal pleura Rib VI Rib X Rib V Superior lobe Costomediastinal recess Inferior lobe Costodiaphragmatic recess Upper lobe Oblique fissure Lower lobe Parietal pleura
How many bronchopulmonary segments in each lung?10
What is the nerve relation anterior and post?Phrenic nerve, sympathetic chain
Describe the course of a clot from deep veins of the calf to pulmonary artery?Popliteal vein → femoral vein → EIV → CIV → IVC → right atrium → AV valve → pulmonary valve → pulmonary artery
Nerve supply of the intercostal muscles?Intercostal nerves and their collateral branches
Branches of the aortic arch?
Subclavian steal syndrome?Retrograde flow of blood flow down to the vertebral artery due to stenoocclusive disease in the subclavian artery proximal to the vertebral artery. This will lead to brainstem ischemia on arm exercise
Thoracic outlet syndrome?Compression of the neurovascular bundle (brachial plexus, subclavian artery) between the scalenus medius and scalenus anterior → neurological and vascular symptoms in the arm
Show on the skeleton where to put a chest tube?5th ICS midaxillary line
Why bradycardia after chest tube insertion?Due to irritation of the vagus nerve. Bronchopulmonary segments of right and left lungs (medial view)
Boundaries of posterior mediastinum?Anterior Pericardium Vertical part of the diaphragm Posterior Lower 8 thoracic vertebrae On each side Mediastinal pleura
Where preganglionic fibres come from?The corresponding spinal nerves T1-L2
What connects it to the spinal nerves?Ganglion + white ramus communicans + grey ramus communicans
How sympathetic nerves leave the sympathetic chain?Through the spinal nerves forming plexuses around blood vessels (cardiac and pulmonary plexuses, greater splanchnic nerve, lesser splanchnic nerve) Paravertebral sympathetic trunk Spinal cord Spinal nerve
Other than the fracture, what are the abnormal signs in this radiograph?1. Abnormal alignment (the distance between the dens and the lateral masses of c1 on both sides is not equal) 2. Prevertebral soft tissue swelling due to fracture edema
Ligaments attached to the odontoid process?• Transverse Atlantal ligament • Apical odontoid ligament • Alar ligament
Type of Atlanto axial joint?Synovial pivot
Ligaments between C1 and C2?• Ant. atlanto axial ligament • Post. atlanto axial ligament • Transverse ligament
What is the first spinous process to be felt?Spinous process of C7 (has a long spine = vertebra prominence)
Demonstrate it on the subject?
Why we cannot feel the upper spinous processes?As they are short, bifid and attached to the nuchal ligament
Atypical cervical vertebrae and the atypical features?• C1 (atlas): no body, no spine • C2 (axis): body projects upwards to form the odontoid process, thick spine • C7 (vertebra prominence): very long spine, smaller foramen transversum
How many vertebrae make the spinal column: How many spinal nerves?• 7 cervical, 8 cervical • 12 thoracic, 12 thoracic • 5 lumbar, 5 lumbar • 5 fused sacral, 5 sacral • 3 fused coccygeal, 1 coccygeal
Structures passing through the intervertebral foramen?• The root of each spinal nerve, • Dorsal root ganglion, • The spinal artery of the segmental artery • Communicating veins between the internal and external plexuses, • Recurrent meningeal (sinuvertebral) nerves • Transforaminal ligaments.
Level of the lumbar puncture?L4/L5. (at the supracrestal line)
Layers to pass through?• Skin, subcutaneus fat, fascia • Supraspinous ligament • Interspinous ligament • Ligamentum flavum • Epidural space • Dura matter • Arachnoid matter • CSF
IV disc anatomy?Internal nucleus pulposus surrounded by fibrocartilagenous annulus fibrosus
Type of IV joint?Secondary cartilaginous joint
Movement on lumbar vertebrae?Flexion, extension, lateral flexion, axial rotation
Level of the spinal cord in newborn and adult?L3 (at birth), L1/2(adult)
Contents of the spinal canal below L2?Cauda equina
Location of the paravertebral venous plexus?• Anterior external vertebral venous plexus, the small system around the vertebral bodies; • Posterior external vertebral venous plexus, the extensive system around the vertebral processes; • Anterior internal vertebral venous plexus, the system running the length of the vertebral canal anterior to the dura • Posterior internal vertebral venous plexus, the system running the length of the vertebral canal posterior to the dura
Contents of epidural space?• Lymphatics • Spinal nerve roots • Loose connective tissue • Fatty tissue • Small arteries • Network of internal vertebral venous plexuses
How does spinal metastasis happen?• Spread from primary tumors is mainly by the arterial route • Retrograde spread through the Batson plexus. • Direct invasion through the intervertebral foramina. Batson venous plexus Is a network of veins with no valves that connect deep pelvic veins draining the bladder, prostate, and rectum to the internal vertebral venous plexus.
Tumors metastasizing to the spine?• Breast • Lung • Thyroid • GI tract • Prostate • Kidney • Lymphoma • Melanoma • Unknown • Others including multiple myeloma - 13%
Structures found at C6?• Termination of the pharynx and beginning of the esophagus • Termination of the larynx and beginning of the trachea • Entry of the vertebral artery to the foramen transversum • Intermediate tendon of omohyoid cross the carotid sheath • Middle thyroid vein emerging from the thyroid gland • Inferior thyroid artery entering the thyroid gland
Demonstrate the boundaries of the posterior triangle on a subject?
Demonstrate the hyoid bone (C3) and the cricoid cartilage (C6) on a subject?
Name the carpal bones.Eight, in two rows of four. • Proximal row, lateral to medial: Scaphoid, Lunate, Triquetrum, Pisiform • Distal row, lateral to medial: Trapezium, Trapezoid, Capitate, Hamate • Mnemonic (Mo's notes): "Scared Lovers Try Positions That They Can't Handle" • The pisiform is a sesamoid in the tendon of flexor carpi ulnaris, and is the only carpal bone with a single articulation (with the triquetral) • The capitate is the largest carpal bone and the first to ossify; the pisiform is the last • The scaphoid is the most commonly fractured. Its waist lies in the floor of the anatomical snuffbox and its tubercle is palpable at the radial border of the palm • Its blood supply enters distally and runs retrograde, so a waist or proximal-pole fracture threatens the proximal fragment with avascular necrosis • The hook of the hamate forms the ulnar wall of Guyon's canal and the medial attachment of the flexor retinaculum; it is fractured by a racquet or golf club handle and can rupture the little finger FDP
Identify Lister's tubercle on this bone.The dorsal tubercle of the radius — the longitudinal ridge on the posterior surface of the lower end of the radius (McMinn labels it dorsal tubercle, F2). • Palpable on the dorsum of the distal radius, roughly in line with the second web space, about a centimetre proximal to the joint line • It acts as a PULLEY for extensor pollicis longus, which passes on its ULNAR side and then turns about 45 degrees laterally to reach the thumb • It therefore separates the second compartment (extensor carpi radialis longus and brevis, radial to it) from the third (extensor pollicis longus, ulnar to it) • On the dry bone you can see the grooves for all six compartments either side of it, separated by low ridges • Clinical importance: extensor pollicis longus ruptures at the tubercle after a minimally displaced distal radius fracture — attrition plus a watershed blood supply. The patient cannot lift the thumb off a flat surface (loss of retropulsion). It is repaired by transferring extensor indicis proprius to EPL • It is the landmark for the dorsal wrist arthroscopy portals — the 3-4 portal lies just distal and ulnar to it • The scapholunate ligament lies deep to it, so it also marks the dorsal approach to the scapholunate interval
What is the significance of Lister's tubercle?It is a pulley and a landmark, and it is where extensor pollicis longus ruptures. • PULLEY: extensor pollicis longus passes on the ULNAR side of the tubercle and turns about 45 degrees laterally around it to reach the thumb. The tubercle converts a straight pull into an oblique one and gives EPL its mechanical advantage for retropulsion • BOUNDARY: it separates the second extensor compartment (extensor carpi radialis longus and brevis, radial to it) from the third (extensor pollicis longus, ulnar to it) • SURFACE LANDMARK: palpable on the dorsum of the distal radius in line with the second web space, about a centimetre proximal to the joint line — the reference point for the dorsal approach to the distal radius and for the 3-4 wrist arthroscopy portal, which lies just distal and ulnar to it • DEEP RELATION: the scapholunate ligament lies directly deep to it, so it marks the scapholunate interval • CLINICAL: EPL ruptures at the tubercle after a MINIMALLY displaced distal radius fracture — the intact tubercle plus fracture haematoma raises pressure in a compartment with a watershed blood supply, and the tendon attrites. Counter-intuitively it is commoner after undisplaced fractures than displaced ones, because the compartment stays closed • The patient cannot lift the thumb off a flat table (loss of retropulsion). Direct repair usually fails because the tendon ends are frayed, so it is treated by transferring extensor indicis proprius to EPL
Identify the flexor retinaculum and give its attachments.The thick white transverse band roofing the carpal tunnel (Gray's Fig. 9.23) — a thickening of deep fascia about 2–3 cm square. • Proximal attachments: the pisiform, and the tubercle of the scaphoid • Distal attachments: the hook of the hamate, and the trapezium • It converts the concave carpal arch into the carpal tunnel • Structures SUPERFICIAL to it: the ulnar nerve and ulnar artery in Guyon's canal, the palmar cutaneous branch of the median nerve, the tendon of palmaris longus (which is partly inserted into it), and the palmar carpal ligament • It gives origin to the thenar and hypothenar muscles • It is the structure divided in carpal tunnel decompression — incise on the ULNAR side of the midline, in line with the radial border of the ring finger, to stay away from the recurrent motor branch and the palmar cutaneous branch
What passes through the carpal tunnel?Ten structures. • 4 tendons of flexor digitorum superficialis • 4 tendons of flexor digitorum profundus • 1 tendon of flexor pollicis longus • The median nerve — the most superficial, lying just deep to the retinaculum, which is why it is compressed first • The nine tendons share two synovial sheaths: the ulnar bursa around the FDS and FDP tendons, and the radial bursa around flexor pollicis longus • NOT in the tunnel: the ulnar nerve and ulnar artery (Guyon's canal), the palmar cutaneous branch of the median nerve, and palmaris longus — all pass superficial to the retinaculum • Caution: Mo's notes also list flexor carpi radialis. Both atlases contradict that — Gray's Fig. 9.25 states plainly that nine tendons and one nerve course through the carpal tunnel, and FCR runs in its own tunnel within a split of the lateral attachment of the retinaculum. Say ten structures, then add that FCR lies in a separate compartment of the retinaculum; that answer is safe whichever version the examiner holds
Identify the median nerve on this prosection.The flat pale nerve emerging from beneath the cut edge of the flexor retinaculum, lying superficial to the long flexor tendons (Gray's Fig. 9.23; labelled 16 on Mo's plate). • It enters the palm THROUGH the carpal tunnel, deep to the flexor retinaculum, and is the most superficial structure in the tunnel — which is why it is compressed first • At the wrist it lies between flexor digitorum superficialis and flexor carpi radialis, just deep and lateral to palmaris longus, the surface guide to it • It gives the palmar cutaneous branch ABOVE the retinaculum, so that branch is spared in carpal tunnel syndrome and sensation over the thenar eminence is preserved • It gives the recurrent (motor) branch at the distal border of the retinaculum to the thenar muscles • Motor supply in the hand: LOAF — Lumbricals 1 and 2, Opponens pollicis, Abductor pollicis brevis, Flexor pollicis brevis • Sensory: palmar surface of the lateral three and a half digits and their nail beds
What is the sensory distribution of the median nerve in the hand?The lateral three and a half digits, but the detail matters. • PALMAR surface of the thumb, index, middle and the RADIAL half of the ring finger • DORSAL surface of the same three and a half digits over the DISTAL phalanges and the nail beds — often the middle phalanges too. This is the point most candidates miss: the median nerve supplies dorsal skin • The skin over the thenar eminence and the central palm is supplied by the PALMAR CUTANEOUS BRANCH, which arises about 5 cm proximal to the wrist and passes SUPERFICIAL to the flexor retinaculum • Therefore in carpal tunnel syndrome the palm and thenar eminence are SPARED and only the digits are numb. Numbness that includes the palm suggests a more proximal lesion such as pronator syndrome, or another diagnosis altogether • That branch is also why the carpal tunnel incision is placed in line with the radial border of the RING finger — too radial and you divide it, leaving a painful neuroma • Autonomous zone (the area supplied by no other nerve, where you test two-point discrimination): the pulp of the INDEX finger. For the ulnar it is the pulp of the little finger, for the radial the first dorsal web space • For contrast: the ulnar nerve takes the medial one and a half digits, palmar and dorsal; the superficial branch of the radial nerve takes the dorsum of the radial three and a half digits PROXIMAL to the DIP joints, plus the skin over the snuffbox
Identify the ulnar artery, and say how it enters the hand.The larger of the two terminal branches of the brachial artery, entering the palm at the radial side of the pisiform (labelled 23 on Mo's plate; seen with the ulnar nerve in Gray's Fig. 9.17–9.19). • It enters SUPERFICIAL to the flexor retinaculum, through Guyon's canal — it does NOT pass through the carpal tunnel • Guyon's canal: floor is the flexor retinaculum, roof is the palmar carpal ligament, medial wall the pisiform, lateral wall the hook of the hamate • The ulnar nerve lies MEDIAL to the artery in the canal, and divides into superficial (sensory) and deep (motor) branches at the distal end • The artery continues as the superficial palmar arch, and gives a deep branch that completes the deep palmar arch with the radial artery • It is the dominant supply to the hand in most people; patency is tested by Allen's test before radial artery cannulation or harvest • Hypothenar hammer syndrome is thrombosis or aneurysm of the ulnar artery in the canal from repeated palmar trauma
What is the name of the space between the pisiform and the hook of the hamate, and which neurovascular bundle passes through it?GUYON'S CANAL — also called the ulnar tunnel or ulnar canal. It transmits the ULNAR NERVE and the ULNAR ARTERY. • BOUNDARIES: medial (ulnar) wall — the pisiform and the tendon of flexor carpi ulnaris; lateral (radial) wall — the hook of the hamate; FLOOR — the flexor retinaculum and the pisohamate ligament; ROOF — the palmar carpal ligament and the muscle palmaris brevis • CONTENTS: the ulnar nerve and the ulnar artery with its venae comitantes. The NERVE lies MEDIAL to the artery • Within the canal the ulnar nerve divides into a SUPERFICIAL branch — mainly sensory to the palmar surface of the medial one and a half digits, with a motor twig to palmaris brevis — and a DEEP branch, which hooks around the hook of the hamate to supply the hypothenar muscles, all the interossei, the medial two lumbricals, adductor pollicis and the deep head of flexor pollicis brevis • Crucially it lies OUTSIDE and SUPERFICIAL to the carpal tunnel, so the ulnar nerve is NOT decompressed by a carpal tunnel release, and the ulnar artery does not pass through the carpal tunnel • CLINICAL: Guyon's canal syndrome. Commonest cause is a GANGLION; also fracture of the hook of the hamate, ulnar artery thrombosis or aneurysm (hypothenar hammer syndrome), and handlebar palsy in cyclists • The distinguishing sign: sensation over the DORSUM of the ulnar hand is PRESERVED, because the dorsal cutaneous branch of the ulnar nerve leaves about 5 cm proximal to the wrist and never enters the canal. Numb dorsum means the lesion is at or above the elbow
How would you test the ulnar artery? Show me Allen's test.Modified Allen's test — it confirms the hand has a dual blood supply before you take or cannulate the radial artery. • WHY: before radial arterial line insertion or ABG, before harvesting the radial artery for coronary grafting, and before raising a radial forearm free flap • TECHNIQUE: elevate the hand and ask the patient to clench the fist tightly for about 30 seconds • Occlude BOTH the radial and ulnar arteries at the wrist with firm digital pressure • Ask them to open the hand — the palm is blanched. Do not let them hyperextend the fingers, which blanches the palm on its own and gives a false positive • Release the ULNAR artery alone, keeping the radial occluded, and time the return of colour to the whole hand • INTERPRETATION: colour returns within 5 to 7 seconds means the ulnar artery and the palmar arches perfuse the hand adequately — safe to proceed. Delay beyond about 10 seconds, or persistent pallor, means inadequate collateral flow and you should NOT take the radial artery • Repeat, releasing the radial artery instead, to assess the ulnar side • The ANATOMY behind it: the superficial palmar arch is complete in only about a third of hands, so collateral flow cannot be assumed • Caution: the test is subjective, has poor inter-observer reliability, and does not reliably predict ischaemic complications. Many units now supplement or replace it with a Doppler or pulse-oximetry (Barbeau) assessment
Identify the superficial palmar arch. What forms it and what lies at its level?The arterial arch lying just deep to the palmar aponeurosis (labelled 29 on Mo's plate; McMinn shows it incomplete on the left hand and complete on the right). • Formed MAINLY by the continuation of the ulnar artery, completed laterally by the superficial palmar branch of the radial artery • Complete in only about a third of hands — McMinn's two specimens show exactly this variation • Lies deep to the palmar aponeurosis but SUPERFICIAL to the long flexor tendons and to the digital branches of the median nerve • Surface marking: its convexity reaches a line across the palm at the level of the distal border of the fully extended thumb • Gives three common palmar digital arteries, plus a proper digital artery to the medial side of the little finger • The deep arch lies about a finger's breadth proximal to it, is formed mainly by the radial artery, and lies deep to the long flexor tendons • Note the relationship reverses distally: in the palm the arteries are superficial to the nerves; in the digits the nerves are superficial to the arteries
Show me how you would check flexor digitorum superficialis and flexor digitorum profundus function.Two separate tests, and the trick in each is to blank out the other muscle. • FDP: hold the PIP joint of the tested finger in full extension, stabilising the middle phalanx, and ask the patient to bend the fingertip. Flexion at the DIP joint means FDP is intact — it is the ONLY flexor of the DIP joint • FDS: hold ALL the other fingers fully extended at MCP, PIP and DIP, then ask the patient to bend the tested finger. Flexion at the PIP with a floppy DIP means FDS is intact • Why holding the others works: the profundus tendons share a common muscle belly, so they cannot act independently. Blocking three fingers in extension takes FDP out of the equation and leaves only FDS to flex the remaining finger • Test both against resistance and ask about pain — pain on resisted flexion with full movement suggests a partial laceration, which can still rupture later • Caution: two normal variants will catch you out. The index finger often has an independent FDP, so the FDS test can fail there in a normal hand; and about 15 percent of people have an absent or non-functioning FDS to the little finger. Always compare with the other hand before calling it a tendon injury • Complete the assessment: test the digital nerves (two-point discrimination on each side of the pulp) and the digital vessels, because they run with the tendons and are injured together • Anatomy behind it: FDS splits at the proximal phalanx (Camper's chiasm) to let FDP through, then inserts on the sides of the middle phalanx; FDP continues to the base of the distal phalanx
Show me the movements of the thumb, and give the muscles and nerve supply for each.The thumb sits rotated 90 degrees to the other digits, so its planes of movement are rotated too — flexion and extension happen in the plane of the palm, abduction and adduction at right angles to it. • Flexion at MCP/IPJ — flexor pollicis longus (median, via anterior interosseous), flexor pollicis brevis (median, recurrent branch) • Extension at MCP/IPJ — extensor pollicis longus and extensor pollicis brevis (radial, via posterior interosseous) • Palmar abduction, away from the plane of the palm — abductor pollicis brevis (median, recurrent branch), abductor pollicis longus (radial, PIN) • Adduction, back towards the palm — adductor pollicis (ulnar, deep branch) • Radial abduction / extension in the plane of the palm — abductor pollicis longus, extensor pollicis brevis (radial, PIN) • Opposition — opponens pollicis, flexor pollicis brevis, abductor pollicis brevis (median, recurrent branch); a combination of abduction, flexion and medial rotation at the saddle-shaped carpometacarpal joint • Quick rule: the thenar muscles are all median (recurrent branch) EXCEPT adductor pollicis, which is ulnar — this is why Froment's sign, where flexor pollicis longus is recruited to pinch, tests the ulnar nerve
Identify all the structures on the dorsum of the hand.Work superficial to deep, proximal to distal. • Skin and subcutaneous tissue — thin and mobile, which is why swelling collects here • Veins: the dorsal venous network draining to the cephalic vein radially and the basilic vein ulnarly • Nerves: the superficial branch of the radial nerve (radial three and a half digits) and the dorsal cutaneous branch of the ulnar nerve (ulnar one and a half) — both lie in the subcutaneous plane • Retinaculum: the extensor retinaculum, with the six synovial sheaths beneath it • Tendons, radial to ulnar: abductor pollicis longus, extensor pollicis brevis, extensor carpi radialis longus, extensor carpi radialis brevis, extensor pollicis longus, extensor digitorum, extensor indicis, extensor digiti minimi, extensor carpi ulnaris • Extensor digitorum tendons linked by the intertendinous connections, ending in the extensor hoods (extensor expansions) with their central slip and two lateral bands • Muscles: four dorsal interossei, abductor digiti minimi, adductor pollicis inserting with the first palmar interosseous into the extensor hood • Bones: radius with Lister's tubercle, ulna with its styloid, carpus, metacarpals, phalanges • Arteries: the radial artery crossing the floor of the snuffbox to reach the first dorsal interosseous space, the dorsal carpal arch and the dorsal metacarpal arteries
Identify the extensor tendons at the back of the hand.Nine tendons, radial to ulnar, in six compartments. • Abductor pollicis longus and Extensor pollicis brevis — the most radial, forming the ANTERIOR (lateral) border of the snuffbox • Extensor carpi radialis longus, inserting on the base of the 2nd metacarpal, and Extensor carpi radialis brevis, on the base of the 3rd — radial to Lister's tubercle • Extensor pollicis longus, hooking round the ULNAR side of Lister's tubercle and crossing obliquely over the two radial extensors to form the POSTERIOR (medial) border of the snuffbox • Extensor digitorum, fanning into four tendons over the dorsum • Extensor indicis — identify it by its position on the ULNAR side of the extensor digitorum tendon to the index finger • Extensor digiti minimi — likewise on the ULNAR side of the extensor digitorum tendon to the little finger. The rule is that both extra tendons sit ulnar to their partner • Extensor carpi ulnaris, in the groove on the dorsum of the ulnar head, inserting on the base of the 5th metacarpal • Linking them: the INTERTENDINOUS CONNECTIONS (juncturae tendinum) between the extensor digitorum tendons over the distal metacarpals, mainly 3-4 and 4-5. They mean that a divided extensor digitorum tendon proximal to them may still produce weak extension, and they can mask a laceration • To test them at the bedside: extensor indicis by extending the index with the other fingers flexed into the palm; extensor digiti minimi the same way for the little finger; extensor pollicis longus by retropulsion, lifting the thumb off a flat table
Name the six extensor compartments of the wrist and their contents.From radial to ulnar, beneath the extensor retinaculum — McMinn's specimen shows all six as blue-injected synovial sheaths. • 1 — Abductor pollicis longus, Extensor pollicis brevis. The compartment of de Quervain's tenosynovitis; Finkelstein's test • 2 — Extensor carpi radialis longus, Extensor carpi radialis brevis. Lies radial to Lister's tubercle; the site of intersection syndrome where compartment 1 crosses over it • 3 — Extensor pollicis longus, turning around the ULNAR side of Lister's tubercle as a pulley. Ruptures here after a minimally displaced distal radius fracture • 4 — Extensor digitorum, Extensor indicis, and the posterior interosseous nerve on the floor of the compartment • 5 — Extensor digiti minimi, overlying the distal radioulnar joint. Ruptures in rheumatoid arthritis — the Vaughan-Jackson lesion • 6 — Extensor carpi ulnaris, in the groove on the dorsum of the ulnar head • Count: 2, 2, 1, 2, 1, 1 • On the dry radius the grooves for each compartment are visible on the posterior surface, separated by ridges, with the dorsal tubercle between compartments 2 and 3 • Note: this is not covered in Mo's notes at all. It is now sourced from McMinn p165, whose caption names compartments (a) to (f), and from the grooves on the dry radius on McMinn p118
What is the insertion of the extensor digitorum tendons?Extensor digitorum has NO bony insertion into the proximal phalanx — that is the whole point of the question. • Over the proximal phalanx the tendon flattens into the EXTENSOR HOOD (extensor expansion) • From the hood it continues as a CENTRAL SLIP, inserting into the base of the MIDDLE phalanx • And as TWO LATERAL BANDS, which pass either side of the PIP joint, converge over the middle phalanx and unite as the TERMINAL TENDON, inserting into the base of the DISTAL phalanx • The lateral bands are joined by the tendons of the INTEROSSEI and LUMBRICALS, which is how the intrinsic muscles extend the interphalangeal joints • Proximally the hood is anchored by the SAGITTAL BANDS, which run round the sides of the MCP joint to the palmar plate and the deep transverse metacarpal ligament. Extensor digitorum extends the MCP joint by pulling on this sling, not by a bony attachment • CLINICAL consequences follow directly: rupture of the central slip gives a BOUTONNIERE deformity, because the lateral bands slip palmar to the axis of the PIP joint and then flex it while hyperextending the DIP • Rupture or avulsion of the terminal tendon gives a MALLET finger • Rupture of a sagittal band lets the extensor tendon sublux ulnarly off the MCP head — boxer's knuckle, and the same process in rheumatoid arthritis
What is the extensor hood, and what is its function?The extensor hood — also called the extensor expansion or dorsal digital expansion — is a triangular aponeurotic sheet spread over the dorsum of the proximal phalanx, formed by the extensor digitorum tendon and joined on each side by the interossei and lumbricals. • PARTS: the sagittal bands proximally, anchoring it round the MCP joint to the palmar plate; the central slip to the middle phalanx; two lateral bands uniting as the terminal tendon to the distal phalanx; the triangular ligament holding the lateral bands dorsally over the middle phalanx; and the oblique retinacular ligament of Landsmeer • FUNCTION 1 — it transmits the pull of extensor digitorum to the MCP joint through the sagittal band sling, and keeps the tendon centred over the dorsum of the metacarpal head • FUNCTION 2, and the important one — it is the mechanism by which the INTRINSIC muscles work. The interossei and lumbricals pass PALMAR to the axis of the MCP joint but insert into the hood, which lies DORSAL to the axes of the PIP and DIP joints. One contraction therefore FLEXES the MCP joint and EXTENDS both interphalangeal joints simultaneously — the lumbrical position, and the grip used for writing • FUNCTION 3 — it links the interphalangeal joints so that their extension is coordinated rather than independent • CLINICAL: this explains the ULNAR CLAW HAND. Losing the interossei and the medial two lumbricals removes MCP flexion and IP extension in the ring and little fingers, so extensor digitorum hyperextends the MCP joints unopposed and flexor digitorum profundus flexes the IP joints • It also explains the intrinsic-plus and intrinsic-minus positions, and why the hand is splinted in the safe position with the MCPs flexed
Give the origin, insertion, action and nerve supply of the interossei.Four dorsal and three palmar, and every one of them is supplied by the deep branch of the ulnar nerve. • DORSAL INTEROSSEI — four, BIPENNATE. ORIGIN: each arises from the ADJACENT SIDES OF TWO metacarpals, so they fill the intermetacarpal spaces. INSERTION: the base of the proximal phalanx and the extensor hood — 1st into the radial side of the index, 2nd into the radial side of the middle, 3rd into the ulnar side of the middle, 4th into the ulnar side of the ring. ACTION: ABDUCT the fingers away from the axis of the hand, which is the middle finger — DAB, Dorsal ABduct • PALMAR INTEROSSEI — three, UNIPENNATE. ORIGIN: each arises from ONE metacarpal only, the palmar surface of the 2nd, 4th and 5th. There is none for the middle finger, because it is the axis. INSERTION: the extensor hood and base of the proximal phalanx of the same digit — 1st into the ulnar side of the index, 2nd into the radial side of the ring, 3rd into the radial side of the little finger. ACTION: ADDUCT the fingers towards the middle finger — PAD, Palmar ADduct • BOTH GROUPS also FLEX the metacarpophalangeal joints and EXTEND the interphalangeal joints, because they pass PALMAR to the MCP axis and insert into the extensor hood, which lies DORSAL to the IP axes • NERVE SUPPLY: the deep branch of the ULNAR nerve (C8, T1) — all seven, without exception • TESTING: the card test (hold a card between the fingers) for the palmar interossei; Froment's sign for adductor pollicis; and look for wasting of the FIRST DORSAL INTEROSSEOUS in the first web space, the earliest visible sign of an ulnar palsy • Note: a few texts describe a small first palmar interosseous to the thumb and so count four. If an examiner says four palmar interossei, that is the one they are counting
What is the neurovascular bundle in the anatomical snuffbox?Careful — the artery and the nerve are in different planes, and that is what the question is testing. • In the FLOOR, running across the scaphoid and trapezium, lies the RADIAL ARTERY. It leaves the anterior forearm, passes deep to the tendons of abductor pollicis longus and extensor pollicis brevis, crosses the box, and then dives between the two heads of the first dorsal interosseous muscle to enter the palm and form the DEEP PALMAR ARCH • This is where you feel the snuffbox pulse, and the site used for distal 'snuffbox' radial arterial access • Crossing the ROOF, in the subcutaneous plane, are the SUPERFICIAL BRANCH OF THE RADIAL NERVE, dividing into its dorsal digital branches, and the origin of the CEPHALIC VEIN from the dorsal venous network — the classic site for a venous cut-down • So there is no true accompanying nerve-with-artery bundle inside the box: the nerve is superficial, in the roof; the artery is deep, in the floor • BORDERS, for completeness: abductor pollicis longus and extensor pollicis brevis anteriorly (laterally), extensor pollicis longus posteriorly (medially), the radial styloid proximally, the base of the first metacarpal distally • CLINICAL: injury to the superficial radial nerve here — from a tight watch strap, handcuffs, or an incision for de Quervain's release — causes WARTENBERG'S SYNDROME, numbness and dysaesthesia over the dorsoradial hand. And tenderness in the box after a fall means a scaphoid fracture until proven otherwise
There is tenderness in the anatomical snuffbox after a fall on the outstretched hand. What is the diagnosis, and what are the common complications?A scaphoid fracture until proven otherwise — the waist of the scaphoid forms the floor of the snuffbox. • Borders of the snuffbox: abductor pollicis longus and extensor pollicis brevis anteriorly (laterally), extensor pollicis longus posteriorly (medially), the styloid process of the radius proximally, the base of the first metacarpal distally • Floor: the scaphoid and the trapezium; the radial artery crosses it, and the superficial branch of the radial nerve and the cephalic vein cross its roof • Confirm clinically with three signs: tenderness in the snuffbox, tenderness over the scaphoid tubercle at the radial border of the palm, and pain on axial compression (telescoping) of the thumb • Imaging: a scaphoid series — PA, lateral, oblique, and PA in ulnar deviation. Up to a quarter of fractures are invisible on the initial films • If the films are negative but the examination is positive, immobilise and either re-image at 10 to 14 days or obtain an MRI, which is the gold standard and is now often done early • Complications: NON-UNION is the commonest — around 10 percent overall, far higher for displaced and proximal-pole fractures • AVASCULAR NECROSIS of the proximal pole. The blood supply comes from the dorsal carpal branch of the radial artery, entering through the dorsal ridge DISTALLY and running retrograde, so the proximal fragment loses its supply. Roughly 100 percent of proximal-pole fractures develop AVN • SNAC WRIST — scaphoid non-union advanced collapse: radioscaphoid arthritis first, then midcarpal arthritis, with a fixed painful stiff wrist • Malunion with a humpback deformity and secondary DISI instability of the lunate • Delayed union, chronic pain, stiffness and reduced grip strength • Why the scaphoid behaves this way: about 80 percent of it is covered in articular cartilage, so there is very little surface for periosteal vessels to enter
Identify this organ.The stomach. • Say how you know, not just what it is: a J-shaped hollow muscular viscus with TWO CURVATURES — a long convex greater curvature on the left and a short concave lesser curvature on the right • The oesophagus enters at the cardia and the wall thickens distally into the pyloric sphincter, which you can feel as a firm ring • The mucosa is thrown into longitudinal folds, the RUGAE, which flatten as the stomach distends • Omenta are attached: the greater omentum hangs from the greater curvature, the lesser omentum runs from the lesser curvature to the liver • Distinguish it from a loop of large bowel, which has taeniae coli, haustra and appendices epiploicae; and from the gall bladder, which is far smaller, thin-walled, blind-ending and bile-stained • Position in the body: epigastrium and left hypochondrium. The cardia lies at T11, about 2 to 3 cm left of the midline; the pylorus lies at L1 on the transpyloric plane of Addison
Identify the parts of the stomach.Four parts, two curvatures, two orifices. • CARDIA — the short segment surrounding the cardiac orifice, where the oesophagus enters at T11 • FUNDUS — the dome above a horizontal line drawn through the cardiac orifice. It lies under the left dome of the diaphragm and holds the gastric bubble seen on an erect film • BODY — the largest part, from the fundus down to the INCISURA ANGULARIS, the notch on the lesser curvature that marks its lower limit • PYLORIC PART — subdivided into the wide pyloric ANTRUM and the narrow pyloric CANAL, about 2.5 cm long, ending at the PYLORUS, the thickened ring of circular muscle at L1. Externally the pylorus is marked by the prepyloric vein of Mayo • CURVATURES: the LESSER curvature on the right, concave, giving attachment to the lesser omentum; the GREATER curvature on the left, convex, giving attachment to the gastrosplenic ligament and the greater omentum • INTERIOR: the rugae, and along the lesser curvature the GASTRIC CANAL or magenstrasse, a groove that channels liquid straight to the pylorus • MUSCLE COATS: three, not two — outer longitudinal, middle circular (thickened to form the pyloric sphincter), and an INNER OBLIQUE layer that is unique to the stomach and slings over the fundus • Clinical: gastric ulcers cluster on the lesser curvature near the incisura; carcinoma is commonest in the antrum and pylorus
Identify the blood supply of the stomach.Every artery comes, directly or indirectly, from the COELIAC TRUNK at T12, which divides into left gastric, splenic and common hepatic. • LESSER CURVATURE: the LEFT GASTRIC artery, arising directly from the coeliac trunk, runs up to the cardia, gives oesophageal branches, then turns down along the lesser curvature. It anastomoses with the RIGHT GASTRIC artery, from the hepatic artery proper • GREATER CURVATURE: the LEFT GASTRO-OMENTAL (gastroepiploic) artery from the SPLENIC artery, anastomosing with the RIGHT GASTRO-OMENTAL artery from the GASTRODUODENAL, which itself comes from the common hepatic • FUNDUS: four or five SHORT GASTRIC arteries from the splenic artery, running in the gastrosplenic ligament, plus a posterior gastric artery • VENOUS DRAINAGE: right and left gastric veins drain DIRECTLY into the portal vein; the right gastro-omental vein drains into the superior mesenteric vein; the left gastro-omental and short gastric veins drain into the splenic vein • LYMPHATICS follow the arteries in four groups, all ending in the coeliac nodes • CLINICAL: the anastomotic arcades are so rich that the stomach survives on a single pedicle — this is what allows a gastric conduit for oesophagectomy, pedicled on the RIGHT GASTRO-OMENTAL artery, with the left gastric divided • The left gastric territory at the lower oesophagus is a site of porto-systemic anastomosis, which is where oesophageal varices form • A posterior duodenal ulcer erodes the gastroduodenal artery and bleeds torrentially
Identify the pancreas on this prosection, and name its parts.A soft, lobulated, greyish-pink retroperitoneal gland lying transversely across the posterior abdominal wall at the level of L1 to L2, about 15 cm long and 80 g. • HEAD — the widest part, lying within the C of the duodenum, to the RIGHT of the superior mesenteric vessels. The common bile duct grooves its posterior surface • UNCINATE PROCESS — a hook of the lower head that projects to the LEFT, passing BEHIND the superior mesenteric artery and vein. The vessels therefore run in front of the uncinate and behind the neck • NECK — about 2 cm, lying directly in front of the confluence of the superior mesenteric and splenic veins forming the portal vein • BODY — crosses the aorta and the first lumbar vertebra. Triangular in cross-section, with anterior, posterior and inferior surfaces and superior, anterior and inferior borders • TAIL — the ONLY intraperitoneal part. It lies between the two layers of the splenorenal ligament and reaches the hilum of the spleen with the splenic vessels • It is both an exocrine gland, acini draining into the duct system, and an endocrine gland, the islets of Langerhans, which are densest in the tail • CLINICAL: tumours of the head obstruct the bile duct and present early with painless obstructive jaundice and a palpable gall bladder (Courvoisier); body and tail tumours present late. The uncinate is the hardest part of a Whipple's resection because of its relationship to the superior mesenteric artery
Describe the development of the pancreas.It develops from TWO buds of endoderm off the caudal FOREGUT at about week 4 to 5, and almost every anomaly follows from how they fuse. • DORSAL BUD — arises directly from the dorsal wall of the duodenum and grows into the dorsal mesentery. It is the larger of the two • VENTRAL BUD — arises from the base of the hepatic diverticulum, so it is carried by the developing BILE DUCT • As the DUODENUM ROTATES to the right and becomes C-shaped, the ventral bud, dragged by the bile duct, swings POSTERIORLY and to the RIGHT and comes to lie BELOW and BEHIND the dorsal bud. The two fuse at about week 7 • VENTRAL bud becomes the UNCINATE PROCESS and the inferior, posterior part of the head • DORSAL bud becomes the rest of the head, the neck, the body and the tail • DUCTS: the MAIN pancreatic duct, of Wirsung, is formed by the WHOLE ventral duct plus the DISTAL part of the dorsal duct, and drains with the bile duct at the major papilla. The ACCESSORY duct, of Santorini, is the PROXIMAL part of the dorsal duct and drains separately at the minor papilla — it persists in about 60 percent of people • The islets differentiate from the duct epithelium in the third month; insulin is secreted from about the fifth month • ANOMALIES: PANCREAS DIVISUM, failure of the two duct systems to fuse, so most of the gland drains through the small accessory duct — the commonest congenital pancreatic anomaly at around 10 percent, associated with recurrent pancreatitis • ANNULAR PANCREAS, where a bifid ventral bud encircles the second part of the duodenum, causing duodenal obstruction with a double-bubble on X-ray, and associated with Down syndrome • ECTOPIC pancreatic tissue, most often in the stomach, duodenum or a Meckel's diverticulum
What are the peritoneal relations of the pancreas?It is RETROPERITONEAL — and specifically SECONDARILY retroperitoneal, because it developed within the dorsal mesentery and was plastered against the posterior abdominal wall as the duodenum rotated. • The one EXCEPTION is the TAIL, which is intraperitoneal, lying between the two layers of the SPLENORENAL (lienorenal) ligament along with the splenic vessels • The peritoneum covering the ANTERIOR SURFACE of the body forms the POSTERIOR WALL OF THE LESSER SAC. The stomach rests on it, separated only by that space • The TRANSVERSE MESOCOLON is attached along the anterior border of the body. Its upper layer sweeps up over the anterior surface into the lesser sac; its lower layer passes down over the duodenum and into the infracolic compartment. The pancreas therefore straddles the supracolic and infracolic compartments • The HEAD sits in the C of the duodenum, behind the lesser sac above the mesocolon and behind greater-sac peritoneum below it • CLINICAL CONSEQUENCES: acute pancreatitis produces a collection in the LESSER SAC, which is where a pseudocyst forms • Enzyme-rich fluid tracks along the transverse mesocolon and down the paracolic gutters, and can reach the retroperitoneum, giving Grey Turner's sign in the flank • Surgically you reach the pancreas either by opening the GASTROCOLIC LIGAMENT into the lesser sac, or by KOCHERISING the duodenum to lift the head forward
What is the blood supply to the uncinate process of the pancreas?The INFERIOR PANCREATICODUODENAL ARTERY, a branch of the SUPERIOR MESENTERIC ARTERY — sometimes arising from the first jejunal branch rather than the trunk itself. • It divides into ANTERIOR and POSTERIOR branches, which anastomose with the corresponding anterior and posterior branches of the SUPERIOR pancreaticoduodenal artery. The superior comes from the GASTRODUODENAL artery, which comes from the common hepatic, which comes from the COELIAC TRUNK • So the head and uncinate lie on the WATERSHED between foregut and midgut — coeliac supply from above, superior mesenteric supply from below, joined by the pancreaticoduodenal arcades • That shared arcade is why the duodenum and the head of the pancreas cannot be resected separately: take one and you devascularise the other. It is the anatomical reason a Whipple's procedure removes both • The DORSAL PANCREATIC artery, usually from the splenic, also contributes branches to the neck and uncinate • In addition, small UNCINATE BRANCHES pass directly from the superior mesenteric artery into the process. These have to be individually identified and ligated, and dissecting the uncinate off the superior mesenteric artery is the most demanding and bloodiest step of a pancreatoduodenectomy • CLINICAL: because of that intimacy, uncinate tumours encase the superior mesenteric artery early and are frequently unresectable at presentation
Describe the ductal drainage system of the pancreas.Two ducts, two papillae. • MAIN PANCREATIC DUCT, the duct of WIRSUNG, runs the entire length of the gland from tail to head, lying nearer the POSTERIOR surface. It receives about twenty short tributaries entering at right angles, giving the herringbone pattern seen at ERCP • In the head it turns downwards and to the right, comes alongside the COMMON BILE DUCT, and the two unite in the AMPULLA OF VATER (the hepatopancreatic ampulla), opening on the MAJOR DUODENAL PAPILLA on the posteromedial wall of the SECOND part of the duodenum, about 8 to 10 cm beyond the pylorus • The ampulla is surrounded by the SPHINCTER OF ODDI, which has separate components around the terminal bile duct (the sphincter of Boyden) and around the terminal pancreatic duct • ACCESSORY DUCT, the duct of SANTORINI, drains the upper part of the head and opens at the MINOR DUODENAL PAPILLA, about 2 cm proximal and slightly anterior to the major papilla. It is present in roughly 60 percent • VARIANTS follow from development: the two may communicate freely, the accessory may be absent, or in PANCREAS DIVISUM they never fuse and the accessory duct carries the bulk of the exocrine output through the small minor papilla • Imaged by ERCP or, non-invasively, by MRCP • CLINICAL: a gallstone impacted at the ampulla obstructs BOTH ducts at once, which is the common-channel explanation for gallstone pancreatitis presenting alongside obstructive jaundice • ERCP itself causes pancreatitis in about 3 to 5 percent • In a Whipple's reconstruction the pancreatic duct is anastomosed to jejunum or to stomach, and that anastomosis is the one that leaks
What vessel lies behind the body of the pancreas?The SPLENIC VEIN. It runs in a groove on the POSTERIOR surface of the body, travelling from the hilum of the spleen rightwards to the neck. • Do not confuse it with the splenic ARTERY, which takes a tortuous course along the SUPERIOR BORDER of the body, in front of the vein and visible from the front of the lesser sac • Also lying behind the body, from the specimen: the ABDOMINAL AORTA and the ORIGIN OF THE SUPERIOR MESENTERIC ARTERY, the LEFT RENAL VEIN crossing between the aorta and the superior mesenteric artery, the LEFT KIDNEY and LEFT SUPRARENAL GLAND, the left crus of the diaphragm, and the INFERIOR MESENTERIC VEIN ascending to join the splenic vein • CLINICAL: this intimacy is the reason chronic pancreatitis, or a carcinoma of the body or tail, causes SPLENIC VEIN THROMBOSIS. That produces LEFT-SIDED, or sinistral, portal hypertension — isolated GASTRIC varices with splenomegaly and a completely normal liver and normal liver function tests • It is the one form of portal hypertension cured by splenectomy • Because the left renal vein passes between the aorta and the superior mesenteric artery just behind the pancreas, the same region is where nutcracker syndrome occurs
What vessel lies behind the neck of the pancreas?The PORTAL VEIN — specifically, its FORMATION. The SUPERIOR MESENTERIC VEIN joins the SPLENIC VEIN behind the neck of the pancreas, at the level of L2, to form the portal vein. • The INFERIOR MESENTERIC VEIN usually joins the splenic vein just before that confluence, though it may join the superior mesenteric vein or the angle itself • The SUPERIOR MESENTERIC ARTERY and VEIN emerge from beneath the LOWER border of the neck to cross in front of the uncinate process and the third part of the duodenum • The superior mesenteric artery itself arises from the aorta at L1, behind the neck and body • SURGICAL IMPORTANCE: this is the key plane in a pancreatoduodenectomy. There are NO venous tributaries entering the superior mesenteric vein or portal vein from their ANTERIOR surface, so a plane can be developed bluntly with a finger between the vein and the back of the neck of the pancreas. The neck is then divided over the vein • Tributaries enter from the SIDES, which is where bleeding comes from if the dissection strays • Whether a tumour abuts, distorts or encases the portal vein and superior mesenteric vein is the single most important determinant of resectability on the staging CT
What is the space between the pancreas and the stomach?The LESSER SAC, or omental bursa. The stomach lies directly on the anterior surface of the pancreas, and the two are separated only by this space; the peritoneum covering the front of the pancreas IS the posterior wall of the sac. • BOUNDARIES — anterior: the stomach, the lesser omentum above it and the gastrocolic ligament below it • posterior: the pancreas, the left kidney and left suprarenal gland, the transverse mesocolon and the diaphragm • right: the epiploic foramen • left: the gastrosplenic and splenorenal ligaments and the spleen • It has a SUPERIOR RECESS behind the caudate lobe of the liver and an INFERIOR RECESS between the layers of the greater omentum • Its ONLY communication with the greater sac is the EPIPLOIC FORAMEN (of Winslow). Its boundaries: ANTERIOR — the free edge of the lesser omentum, the hepatoduodenal ligament, containing the portal triad; POSTERIOR — the inferior vena cava; SUPERIOR — the caudate lobe of the liver; INFERIOR — the first part of the duodenum • CLINICAL: a pancreatic PSEUDOCYST collects in the lesser sac, which is why it is drained by cystogastrostomy through the posterior wall of the stomach • To expose the pancreas you divide the GASTROCOLIC LIGAMENT and enter the sac • And the PRINGLE MANOEUVRE is performed by passing a finger through the epiploic foramen and compressing the free edge of the lesser omentum between finger and thumb
What are the peritoneal relations of the duodenum?Only the FIRST 2 to 3 cm is intraperitoneal — everything else is secondarily retroperitoneal, and the exceptions matter clinically. • The proximal 2 to 3 cm of the FIRST part, the DUODENAL CAP, is INTRAPERITONEAL and mobile. It has the LESSER OMENTUM attached to its upper border and the GREATER OMENTUM to its lower border • The DISTAL first part, and the whole of the SECOND, THIRD and FOURTH parts, are SECONDARILY RETROPERITONEAL — they began in the dorsal mesentery and were plastered onto the posterior abdominal wall when the gut rotated • The duodenum becomes intraperitoneal again at the DUODENOJEJUNAL FLEXURE, which is suspended by the SUSPENSORY MUSCLE OF THE DUODENUM, the LIGAMENT OF TREITZ, a fibromuscular band running up to the right crus of the diaphragm • The TRANSVERSE MESOCOLON crosses the front of the second part, so the duodenum spans the supracolic and infracolic compartments • CLINICAL CONSEQUENCES: the duodenal cap is where duodenal ulcers form. An ANTERIOR ulcer perforates into the peritoneal cavity, giving free gas under the diaphragm and generalised peritonitis; a POSTERIOR ulcer cannot perforate freely and instead erodes the gastroduodenal artery and bleeds • A retroperitoneal duodenal injury leaks into the retroperitoneum, produces few early signs and is notoriously missed on the initial CT • The duodenum is mobilised by KOCHERISATION, incising the peritoneum along its lateral border and lifting the C-loop and head of pancreas forwards off the inferior vena cava
What vessel lies behind the first part of the duodenum?The GASTRODUODENAL ARTERY. • Behind the first part, listed from front to back: the GASTRODUODENAL ARTERY, then the COMMON BILE DUCT, then the PORTAL VEIN, and behind them the INFERIOR VENA CAVA • In front of and above it lie the quadrate lobe of the liver and the gall bladder — which is why a chronically inflamed gall bladder can fistulate into the duodenum and let a stone pass to cause gallstone ileus • The gastroduodenal artery is a branch of the COMMON HEPATIC ARTERY, and it gives the superior pancreaticoduodenal and right gastro-omental arteries • CLINICAL: a POSTERIOR duodenal ulcer erodes the gastroduodenal artery and causes torrential upper gastrointestinal haemorrhage. It is controlled at operation by duodenotomy and UNDERRUNNING the vessel with a three-point ligation — above, below and medially, to catch the transverse pancreatic branch — taking care not to include the common bile duct in the stitch • Note: you asked whether this is about SMA syndrome. It is not — that is a different question. Superior mesenteric artery syndrome involves compression of the THIRD part of the duodenum in the aortomesenteric angle. The superior mesenteric artery has no relation to the first part. Keep the two separate: gastroduodenal artery behind D1, superior mesenteric artery in front of D3
In which part of the peritoneum does the hepatic artery pass?In the FREE RIGHT EDGE of the LESSER OMENTUM — the part named the HEPATODUODENAL LIGAMENT. • The lesser omentum runs from the lesser curvature of the stomach and the first part of the duodenum up to the porta hepatis and the fissure for the ligamentum venosum. Its left portion is the HEPATOGASTRIC ligament; its thickened right free edge is the HEPATODUODENAL ligament • That free edge forms the ANTERIOR BOUNDARY OF THE EPIPLOIC FORAMEN, and it carries the PORTAL TRIAD • Arrangement within it: the HEPATIC ARTERY PROPER on the LEFT, the COMMON BILE DUCT on the RIGHT, and the PORTAL VEIN POSTERIOR to both • Before reaching it, the COMMON HEPATIC ARTERY runs to the right along the upper border of the pancreas, in the posterior wall of the LESSER SAC, then turns forwards into the free edge, giving off the gastroduodenal artery as it does so • CLINICAL: the PRINGLE MANOEUVRE — pass a finger through the epiploic foramen behind the free edge and compress the ligament between finger and thumb, occluding both the hepatic artery and the portal vein to control bleeding from a liver injury. If the bleeding does not stop, it is coming from the hepatic veins or the retrohepatic inferior vena cava, not from the inflow • The same free edge is skeletonised in a lymphadenectomy, and it is where an aberrant right hepatic artery from the superior mesenteric artery runs, posterolateral to the bile duct, in about 15 percent of people
What vessels lie in front of and behind the third part of the duodenum?IN FRONT: the SUPERIOR MESENTERIC ARTERY and the SUPERIOR MESENTERIC VEIN, descending in the ROOT OF THE MESENTERY as it crosses the duodenum obliquely. BEHIND: the ABDOMINAL AORTA at L3, the INFERIOR VENA CAVA, the right ureter, the right gonadal vessels and the right psoas major. • The third part therefore lies clamped in the AORTOMESENTERIC ANGLE — superior mesenteric artery in front, aorta behind • That angle is normally 25 to 60 degrees, and the aortomesenteric distance 10 to 28 mm. It is held open by the RETROPERITONEAL FAT PAD around the origin of the superior mesenteric artery • CLINICAL — SUPERIOR MESENTERIC ARTERY SYNDROME, also called Wilkie's syndrome or cast syndrome. Loss of that fat pad narrows the angle to below about 25 degrees and the third part of the duodenum is compressed • Causes are anything producing rapid weight loss: anorexia nervosa, malignancy, burns, malabsorption, prolonged bed rest — and classically after scoliosis correction or spinal casting, which lengthens the spine and stretches the mesenteric root • Presentation: post-prandial epigastric pain, bilious vomiting, early satiety and further weight loss, which narrows the angle further — a vicious cycle. Symptoms are relieved by lying prone or in the left lateral position • Diagnosis: CT or MR angiography measuring the angle and distance, or a barium study showing an abrupt vertical cut-off in the third part with proximal dilatation • Treatment: nutritional support first, with nasojejunal feeding past the obstruction to restore the fat pad. If that fails, DUODENOJEJUNOSTOMY, or division of the ligament of Treitz with mobilisation of the duodenum, which is Strong's procedure
Name the muscles of the rotator cuff, and give their origin and insertion.Four muscles — SITS. Three insert on the greater tuberosity, one on the lesser. • SUPRASPINATUS — origin: the medial two-thirds of the SUPRASPINOUS FOSSA of the scapula. Insertion: the SUPERIOR facet of the greater tuberosity. Nerve: suprascapular (C5,6). Initiates the first 15 degrees of abduction, then assists deltoid • INFRASPINATUS — origin: the INFRASPINOUS FOSSA. Insertion: the MIDDLE facet of the greater tuberosity. Nerve: suprascapular (C5,6). Lateral rotation • TERES MINOR — origin: the upper two-thirds of the LATERAL (axillary) BORDER of the scapula. Insertion: the INFERIOR facet of the greater tuberosity. Nerve: AXILLARY (C5,6) — the odd one out. Lateral rotation • SUBSCAPULARIS — origin: the SUBSCAPULAR FOSSA on the costal surface. Insertion: the LESSER TUBEROSITY. Nerve: upper and lower subscapular (C5,6,7). Medial rotation. The only anterior one and the only one on the lesser tuberosity • FUNCTION as a group: the tendons blend with the joint capsule and hold the humeral head centred in the shallow glenoid, giving deltoid a fulcrum to abduct against. Without them deltoid simply shrugs the head upwards • The ROTATOR INTERVAL, between supraspinatus and subscapularis, transmits the long head of biceps • CLINICAL: supraspinatus tears most often, at a relatively avascular critical zone about 1 cm from its insertion, and is the tendon impinged beneath the coracoacromial arch — painful arc 60 to 120 degrees. Test supraspinatus with Jobe's empty-can, infraspinatus and teres minor with resisted external rotation and the lag signs, subscapularis with Gerber's lift-off and the belly-press • Caution: TERES MAJOR is NOT part of the cuff. It is a medial rotator, supplied by the lower subscapular nerve, and inserts on the medial lip of the intertubercular groove. Nor is the long head of biceps. Both are common traps
Identify the acromion and the coracoid process on this scapula.Both are the landmarks the whole shoulder is built around. • ACROMION — the flattened, expanded LATERAL END OF THE SPINE of the scapula, projecting laterally and forwards to overhang the glenoid. It is the most lateral bony point of the shoulder and is subcutaneous throughout. It articulates with the lateral end of the clavicle at the ACROMIOCLAVICULAR JOINT. Attachments: DELTOID from its lateral border and inferior surface, TRAPEZIUS into its medial border and upper surface • CORACOID PROCESS — a hooked projection from the upper border of the scapula at the base of the neck, pointing forwards and laterally. Palpable about 2 cm inferomedial to the tip of the clavicle, in the deltopectoral groove. From its TIP arise the SHORT HEAD OF BICEPS and CORACOBRACHIALIS as a conjoint tendon; from its medial border, PECTORALIS MINOR inserts. Ligaments: coracoacromial, coracoclavicular (conoid medially and trapezoid laterally), and coracohumeral • Together the acromion, the coracoid and the coracoacromial ligament between them form the CORACOACROMIAL ARCH — the rigid roof over the supraspinatus tendon and the subacromial bursa, and therefore the site of impingement • CLINICAL: acromial morphology is graded by Bigliani — type I flat, type II curved, type III hooked, the last strongly associated with impingement and cuff tears. Acromioclavicular joint disruption is graded by Rockwood, using the coracoclavicular distance • The coracoid is called the LIGHTHOUSE OF THE SHOULDER — every important neurovascular structure lies MEDIAL to it, so you never dissect medial to the coracoid. It is osteotomised and transferred to the anterior glenoid in the Latarjet procedure for recurrent anterior instability
Which muscles are responsible for upward and downward rotation of the scapula? Give their origin, insertion and nerve supply.Two opposing groups, and upward rotation works as a force couple of three muscle pulls. • UPWARD ROTATION — the glenoid is turned to face upwards, which is what allows abduction beyond 90 degrees • TRAPEZIUS, upper and lower fibres. Origin: external occipital protuberance, ligamentum nuchae and the spinous processes of C7 to T12. Insertion: lateral third of the clavicle, the acromion, and the spine of the scapula. Nerve: SPINAL ACCESSORY, cranial nerve XI, with proprioceptive fibres from C3 and C4. The upper fibres elevate the lateral angle while the lower fibres depress the medial end of the spine • SERRATUS ANTERIOR. Origin: the outer surfaces of the upper eight or nine RIBS. Insertion: the whole length of the COSTAL surface of the MEDIAL BORDER of the scapula, concentrated at the inferior angle. Nerve: LONG THORACIC nerve (C5, C6, C7). It is the strongest upward rotator, and it also protracts the scapula • DOWNWARD ROTATION — returning the scapula to rest, and adducting and extending the arm • RHOMBOID MAJOR and MINOR. Origin: spinous processes T2 to T5 for major, C7 and T1 with the lower ligamentum nuchae for minor. Insertion: the medial border of the scapula, below the spine for major and at the level of the spine for minor. Nerve: DORSAL SCAPULAR (C5) • LEVATOR SCAPULAE. Origin: the transverse processes of C1 to C4. Insertion: the medial border above the spine, up to the superior angle. Nerve: DORSAL SCAPULAR (C5) plus C3 and C4 • Assisted by PECTORALIS MINOR (medial pectoral, C8, T1) and LATISSIMUS DORSI • CLINICAL: LONG THORACIC NERVE injury — from axillary clearance, chest drain insertion, or a blow to the shoulder — paralyses serratus anterior and gives MEDIAL WINGING of the scapula, exaggerated by pushing against a wall, with loss of abduction beyond 90 degrees • SPINAL ACCESSORY injury, classically from a lymph node biopsy in the posterior triangle, gives a drooping shoulder with LATERAL winging and difficulty abducting
Which nerve is related to the spiral groove of the humerus? Describe the injury, and explain why the hand grip is lost.The RADIAL NERVE, together with the PROFUNDA BRACHII (deep brachial) artery. • It runs in the RADIAL or SPIRAL GROOVE on the POSTERIOR surface of the mid-shaft of the humerus, between the lateral and medial heads of triceps, spiralling from medial to lateral, then pierces the lateral intermuscular septum to enter the anterior compartment between brachialis and brachioradialis • MECHANISM: mid-shaft humeral fracture, because the nerve is tethered against the bone; Saturday night palsy from falling asleep with the arm over a chair back; crutch palsy; and tourniquet palsy • CLINICAL PICTURE — WRIST DROP. Motor loss of every wrist and finger extensor: extensor carpi radialis longus and brevis, extensor carpi ulnaris, extensor digitorum, extensor indicis, extensor digiti minimi, and the thumb extensors, plus brachioradialis and supinator • TRICEPS IS SPARED, because its branches leave the nerve ABOVE the groove. That is how you distinguish a spiral groove lesion from one in the axilla, where triceps is also lost • Sensory loss is confined to a small patch on the dorsum of the FIRST WEB SPACE, the autonomous zone of the superficial branch • WHY THE GRIP GOES — and this is the point of the question. The radial nerve supplies NO long flexor of the fingers, so the flexors themselves are perfectly normal. The grip fails because WRIST EXTENSION is lost. A strong fist requires the wrist to be held in about 20 to 30 degrees of EXTENSION, which places flexor digitorum superficialis and profundus at their optimal length on the length-tension curve. With the wrist dropped into flexion those muscles are already shortened and become ACTIVELY INSUFFICIENT, generating far less force • Demonstrate it: support the patient's wrist in extension with your hand and the grip returns immediately. That is what the examiner wants to see • RECOVERY: in a closed fracture most are neuropraxias and 70 to 90 percent recover; splint the wrist, observe for three to four months, and use EMG. Explore early for an open fracture, for a new deficit appearing after manipulation, or in a Holstein-Lewis spiral fracture of the distal third where the nerve can be trapped at the lateral intermuscular septum
Identify the medial condyle on this humerus. Which nerve is related to it, and what injury results?The structure is the MEDIAL EPICONDYLE, and the nerve is the ULNAR NERVE. • The medial epicondyle is the blunt projection on the medial side of the distal humerus. It is MORE PROMINENT than the lateral, is entirely NON-ARTICULAR, and is subcutaneous • Attachments: the COMMON FLEXOR ORIGIN — pronator teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris and flexor digitorum superficialis — and the ulnar collateral ligament • The ULNAR NERVE lies in a groove on its POSTERIOR surface, within the CUBITAL TUNNEL, roofed by Osborne's ligament, the arcuate band between the two heads of flexor carpi ulnaris. It is subcutaneous here, which is why it is the funny bone • CUBITAL TUNNEL SYNDROME is the second commonest entrapment neuropathy after carpal tunnel. Compression worsens in FLEXION, which both stretches the nerve and narrows the tunnel. Paraesthesia in the little and ring fingers, worse at night and with the elbow bent, then weakness of grip and pinch • Signs: wasting of the first dorsal interosseous and the hypothenar eminence, clawing of the ring and little fingers, positive Froment's sign, Tinel's over the tunnel, and a positive elbow flexion test • LOCALISING SIGN: sensory loss covers the medial one and a half digits PALMAR AND DORSAL, because the dorsal cutaneous branch leaves 5 cm above the wrist and is caught by an elbow lesion but spared at Guyon's canal • THE ULNAR PARADOX: a HIGH lesion at the elbow causes LESS clawing than a low lesion at the wrist, because flexor digitorum profundus to the ring and little fingers is also paralysed and cannot flex the interphalangeal joints. The more proximal the lesion, the less the deformity • TRAUMA: medial epicondyle avulsion in children (little leaguer's elbow) — remember CRITOE, the medial epicondyle is the last centre to fuse; supracondylar fracture; and TARDY ULNAR PALSY years after a malunited childhood fracture leaving cubitus valgus • TREATMENT: activity modification and night splinting in extension; then decompression, with or without anterior transposition, or medial epicondylectomy • Note: strictly the CONDYLE of the humerus is the articular part — capitulum and trochlea. What you are pointing at is the medial EPICONDYLE. Use that word at the station
To achieve full abduction of the arm, which joints are involved?FOUR joints, and you must name all four — three synovial and one functional. • 1. GLENOHUMERAL JOINT — contributes about 120 degrees of the 180 • 2. SCAPULOTHORACIC ARTICULATION — not a true synovial joint but a functional gliding surface between subscapularis and serratus anterior. The scapula rotates upwards about 60 degrees • 3. ACROMIOCLAVICULAR JOINT — permits about 20 to 30 degrees of rotation of the scapula on the clavicle • 4. STERNOCLAVICULAR JOINT — the ONLY true synovial articulation between the upper limb and the axial skeleton. The clavicle elevates about 30 to 40 degrees and rotates posteriorly about 40 to 50 degrees on its long axis • SCAPULOHUMERAL RHYTHM: overall 2 to 1. For every 3 degrees of abduction, 2 occur at the glenohumeral joint and 1 at the scapulothoracic. The first 30 degrees is the SETTING PHASE and is almost purely glenohumeral; the 2 to 1 ratio holds thereafter • SEQUENCE OF MUSCLES: supraspinatus initiates the first 15 degrees, the middle fibres of deltoid carry it to about 90, and beyond 90 trapezius and serratus anterior rotate the scapula upwards to complete it. The humerus must also EXTERNALLY ROTATE to bring the greater tuberosity clear of the acromion, or it impinges • Add that thoracic spine extension and contralateral side flexion contribute to true full elevation • CLINICAL: a completely stiff or arthrodesed glenohumeral joint still gives about 60 degrees of abduction through scapular rotation alone, which is why an isolated glenohumeral problem is easily missed. To test glenohumeral movement in isolation you must hold the scapula still with your other hand. And loss of the final part of abduction after a long thoracic nerve palsy is a SCAPULAR problem, not a shoulder joint one
Give the origin and insertion of the hip flexors.The principal flexor is ILIOPSOAS, which is two muscles with a common insertion. • PSOAS MAJOR — origin: the TRANSVERSE PROCESSES of L1 to L5, and the BODIES and INTERVERTEBRAL DISCS of T12 to L5. Insertion: the LESSER TROCHANTER of the femur. Nerve: the anterior rami of L1, L2 and L3 directly, not through the femoral nerve • ILIACUS — origin: the upper two-thirds of the ILIAC FOSSA, the inner lip of the iliac crest and the ala of the sacrum. Insertion: joins the psoas tendon into the LESSER TROCHANTER. Nerve: FEMORAL nerve (L2, L3) • The secondary flexors • RECTUS FEMORIS — origin: STRAIGHT HEAD from the ANTERIOR INFERIOR ILIAC SPINE, REFLECTED HEAD from the groove above the acetabular rim. Insertion: base of the patella and, through the patellar ligament, the tibial tuberosity. Nerve: femoral (L2,3,4). The only head of quadriceps that crosses the hip • SARTORIUS — origin: the ANTERIOR SUPERIOR ILIAC SPINE and the notch below it. Insertion: the upper medial surface of the tibia as part of the pes anserinus. Nerve: femoral (L2,3). The longest muscle in the body • PECTINEUS — origin: the pecten pubis. Insertion: the pectineal line of the femur, just below the lesser trochanter. Nerve: femoral, sometimes with an obturator contribution • TENSOR FASCIAE LATAE — origin: the outer lip of the iliac crest between the ASIS and the iliac tubercle. Insertion: the ILIOTIBIAL TRACT. Nerve: SUPERIOR GLUTEAL (L4,5) • Adductor longus and gracilis assist when the hip is already extended • CLINICAL: a psoas abscess tracks down inside the sheath from the retroperitoneum into the femoral triangle, holding the hip flexed with a positive psoas stretch test. Sources include a tuberculous vertebral body and Crohn's disease. In adolescent athletes the ASIS is avulsed by sartorius at a sprint start and the AIIS by rectus femoris on kicking
Identify the ASIS. Which nerve passes medial to it, and what condition is caused by its compression?The ANTERIOR SUPERIOR ILIAC SPINE — the anterior end of the iliac crest, the palpable prominence at the front of the pelvis. The nerve is the LATERAL CUTANEOUS NERVE OF THE THIGH, and compressing it causes MERALGIA PARAESTHETICA. • Attachments at the ASIS: the INGUINAL LIGAMENT medially, SARTORIUS from its anterior surface, and TENSOR FASCIAE LATAE from the crest just posterolateral to it • THE NERVE: the lateral cutaneous nerve of the thigh, also called the lateral femoral cutaneous nerve, from the lumbar plexus, roots L2 and L3. It emerges at the lateral border of psoas, crosses iliacus obliquely beneath the iliac fascia, and enters the thigh just MEDIAL and INFERIOR to the ASIS, passing either beneath or through the inguinal ligament, usually 1 to 2 cm medial to the spine • It is PURELY SENSORY, supplying the skin of the anterolateral thigh from the greater trochanter down to just above the knee • MERALGIA PARAESTHETICA — from meros, thigh, and algos, pain. Burning pain, numbness and paraesthesia over the anterolateral thigh, with NO motor weakness and NO reflex change. That is what separates it from an L2 or L3 radiculopathy, which would weaken the quadriceps and depress the knee jerk • Worse on standing, walking or extending the hip; relieved by sitting • CAUSES: obesity, pregnancy, tight belts, low-slung trousers, tool belts, body armour and seat belts. Iatrogenic causes matter for the exam — ANTERIOR ILIAC CREST BONE GRAFT HARVEST, the direct anterior approach to the hip, appendicectomy, hernia repair, and prolonged prone positioning • DIAGNOSIS is clinical: a positive pelvic compression test and Tinel's sign just medial to the ASIS, confirmed if necessary by a diagnostic local anaesthetic block • MANAGEMENT: remove the cause and lose weight — most settle. Then local anaesthetic and steroid injection; refractory cases have neurolysis or nerve division • The nerve's course relative to the ASIS is highly variable, which is why iliac crest graft should be taken at least 3 cm POSTERIOR to the spine
Identify the pubic tubercle.A small blunt palpable projection on the UPPER BORDER OF THE BODY OF THE PUBIS, about 2.5 to 3 cm lateral to the pubic symphysis, at the medial end of the pubic crest. • It is the key landmark of the groin • The MEDIAL end of the INGUINAL LIGAMENT attaches to it — the lateral end is the ASIS • The SUPERFICIAL INGUINAL RING lies immediately above and lateral to it • The spermatic cord, or the round ligament in the female, lies directly on it — you palpate the cord by rolling it against the tubercle • Other attachments: the lacunar ligament, the conjoint tendon, the reflected part of the inguinal ligament, and the origin of adductor longus just below it • THE REASON IT IS ASKED: it is the landmark that distinguishes an inguinal from a femoral hernia. An INGUINAL hernia emerges ABOVE and MEDIAL to the pubic tubercle. A FEMORAL hernia emerges BELOW and LATERAL to it. Say that sentence and the question is answered • It is also where the mesh is anchored medially in an open inguinal hernia repair, and it is palpable even in an obese patient by tracing the tendon of adductor longus upwards to its origin • It lies at approximately the same horizontal level as the tip of the greater trochanter, which is useful when assessing a shortened limb
Which muscles attach to the ASIS?Two muscles and one ligament — and the examiner is testing whether you can separate the ASIS from the AIIS. • FROM THE ASIS: • SARTORIUS — from the anterior surface of the spine and the notch just below it. It runs obliquely across the thigh to insert on the upper medial surface of the tibia as part of the pes anserinus. Femoral nerve • TENSOR FASCIAE LATAE — from the outer lip of the iliac crest immediately posterolateral to the spine, and from its lateral aspect. It inserts into the ILIOTIBIAL TRACT about a third of the way down the thigh. Superior gluteal nerve • The INGUINAL LIGAMENT, which is the rolled-under lower border of the external oblique aponeurosis, attaches to the ASIS laterally and runs to the pubic tubercle medially. The fascia lata and the deep circumflex iliac vessels are also related to it • FROM THE AIIS, which is the trap: the STRAIGHT HEAD OF RECTUS FEMORIS. The reflected head arises from the groove above the acetabular rim, and the ILIOFEMORAL LIGAMENT also arises from the AIIS • CLINICAL: apophyseal AVULSION FRACTURES in adolescent athletes follow directly from these attachments. The ASIS is avulsed by SARTORIUS at the explosive start of a sprint; the AIIS is avulsed by RECTUS FEMORIS during a kick. Both are managed conservatively with rest, analgesia and protected weight bearing, with surgery reserved for displacement of more than 2 to 3 cm
Give the origin and insertion of gluteus medius. What is its function during walking?ORIGIN: the OUTER SURFACE OF THE ILIUM, between the POSTERIOR and ANTERIOR GLUTEAL LINES, and from the gluteal aponeurosis covering it. INSERTION: an oblique ridge on the LATERAL SURFACE OF THE GREATER TROCHANTER of the femur. • NERVE: the SUPERIOR GLUTEAL nerve, L4, L5 and S1, which leaves the pelvis through the greater sciatic foramen ABOVE piriformis and runs forwards between gluteus medius and minimus. Blood supply: the superior gluteal artery • FUNCTION IN WALKING — and this is the real question. Its principal role is NOT to abduct the leg in the air. During the STANCE PHASE, when the opposite foot is off the ground, gluteus medius and minimus on the WEIGHT-BEARING side contract to hold the pelvis LEVEL and stop it dropping on the unsupported swinging side. In other words they abduct the trunk on a fixed femur • They also produce the medial rotation that carries the pelvis forward over the planted leg, and they control the rate of pelvic drop eccentrically • TRENDELENBURG — get the sidedness right. If the abductors of the STANDING side fail, the pelvis DROPS on the OPPOSITE, unsupported side. So a positive Trendelenburg test indicates weakness on the side being STOOD ON • Bilateral weakness gives a waddling gait; unilateral gives the Trendelenburg lurch, where the trunk is thrown over the affected hip to shift the centre of gravity and reduce the abductor force required • CAUSES, grouped: nerve — superior gluteal nerve injury from an injection in the wrong quadrant or a lateral approach to the hip; muscle — detachment after hip surgery, greater trochanteric avulsion, myopathy; joint — any painful hip, or an unstable one such as a dislocation or DDH; and an abnormal fulcrum — fractured neck of femur, coxa vara, or a slipped upper femoral epiphysis • This lever arm is why femoral OFFSET is restored in a total hip replacement, and why the abductors must not be split more than 5 cm above the tip of the greater trochanter, or the superior gluteal nerve is cut
Which is the main flexor of the hip, and where is it inserted?ILIOPSOAS, and it inserts into the LESSER TROCHANTER of the femur. • It is by far the most powerful flexor of the hip, and it is really two muscles with a common tendon • PSOAS MAJOR arises from the transverse processes of L1 to L5 and from the bodies and intervertebral discs of T12 to L5. ILIACUS arises from the upper two-thirds of the iliac fossa • They converge, pass beneath the INGUINAL LIGAMENT through the MUSCULAR LACUNA, lateral to the femoral nerve, cross in front of the capsule of the hip joint and the superior pubic ramus, and insert by a common tendon into the LESSER TROCHANTER on the posteromedial aspect of the proximal femur • NERVE: psoas from the anterior rami of L1 to L3 directly; iliacus from the FEMORAL nerve (L2, L3) • The ILIOPECTINEAL BURSA separates the tendon from the hip capsule and communicates with the joint in about 15 percent of people • ACTIONS: flexes the hip. When the femur is fixed it flexes the trunk on the thigh — sitting up from lying. Psoas also side-flexes and stabilises the lumbar spine • CLINICAL, and this is worth volunteering: an ISOLATED AVULSION FRACTURE OF THE LESSER TROCHANTER in an adult, outside the adolescent athlete, is a PATHOLOGICAL FRACTURE UNTIL PROVEN OTHERWISE — think metastasis and image the whole femur • A PSOAS ABSCESS holds the hip flexed and externally rotated, with pain on passive extension, and may point below the inguinal ligament in the femoral triangle • ILIOPSOAS TENDONITIS and internal snapping hip occur as the tendon flicks over the iliopectineal eminence or the femoral head, and it is a recognised cause of groin pain after a total hip replacement with an oversized or prominent acetabular component • The FEMORAL NERVE lies in the groove between psoas and iliacus beneath the iliac fascia, so a retroperitoneal haematoma there — in an anticoagulated patient — compresses it and gives a weak quadriceps with an absent knee jerk
What is the origin and insertion of quadratus femoris?ORIGIN: the upper part of the LATERAL BORDER OF THE ISCHIAL TUBEROSITY. INSERTION: the QUADRATE TUBERCLE on the INTERTROCHANTERIC CREST of the femur, and the bone just below it. • NERVE: the NERVE TO QUADRATUS FEMORIS, L4, L5 and S1, from the sacral plexus. It leaves the pelvis through the greater sciatic foramen BELOW piriformis and runs DEEP to the sciatic nerve and deep to the gemelli and obturator internus — which is why it is so easily missed in dissection. It also supplies inferior gemellus and gives an articular branch to the hip joint • ACTION: LATERAL (external) rotation of the extended thigh; it also adducts and helps to stabilise the femoral head in the acetabulum • RELATIONS: it is the LOWEST of the short lateral rotators. From above downwards the group runs PIRIFORMIS, SUPERIOR GEMELLUS, OBTURATOR INTERNUS, INFERIOR GEMELLUS, QUADRATUS FEMORIS, with OBTURATOR EXTERNUS deep to it. The sciatic nerve crosses superficial to it • The MEDIAL CIRCUMFLEX FEMORAL ARTERY appears at its UPPER border, between it and the inferior gemellus, and runs to the trochanteric anastomosis. In the adult this is the MAIN blood supply to the head of the femur • CLINICAL: that arterial relationship is precisely why the POSTERIOR APPROACH to the hip, which divides the short external rotators, endangers the blood supply to the femoral head, and why an intracapsular fracture displaced enough to tear those retinacular vessels is treated by replacing the head rather than fixing it • ISCHIOFEMORAL IMPINGEMENT is narrowing of the space between the ischial tuberosity and the lesser trochanter, pinching quadratus femoris and causing deep buttock pain with oedema of the muscle on MRI
Identify the following on this prosection: vastus lateralis, tensor fasciae latae, iliotibial tract, rectus femoris, sartorius, femoral artery and femoral vein.Work from lateral to medial, superficial to deep. • TENSOR FASCIAE LATAE — the short, flat muscle in the upper LATERAL thigh, arising from the outer lip of the iliac crest just behind the ASIS and ending about a third of the way down the thigh • ILIOTIBIAL TRACT — the glistening white longitudinal band continuing from it down the lateral thigh. It is the thickened lateral part of the FASCIA LATA, inserting into GERDY'S TUBERCLE on the anterolateral tibial condyle • VASTUS LATERALIS — the large fleshy mass lateral to rectus femoris and deep to the tract. The largest component of quadriceps; origin from the greater trochanter, intertrochanteric line and the lateral lip of the linea aspera • RECTUS FEMORIS — the superficial strap running straight down the MIDLINE of the front of the thigh, from the anterior inferior iliac spine to the base of the patella. Bipennate, and the only head of quadriceps crossing the hip • SARTORIUS — the narrow ribbon crossing the thigh OBLIQUELY from the ASIS downwards and medially to the upper medial tibia. It forms the LATERAL border of the femoral triangle and the ROOF of the adductor canal. The longest muscle in the body • FEMORAL ARTERY — enters the thigh at the MID-INGUINAL POINT, midway between the ASIS and the pubic symphysis. It runs in the femoral triangle and gives PROFUNDA FEMORIS about 4 cm below the inguinal ligament, then passes through the adductor hiatus to become the popliteal artery • FEMORAL VEIN — lies MEDIAL to the artery at the inguinal ligament, but spirals to lie POSTERIOR to it at the apex of the triangle and in the adductor canal. It receives the great saphenous vein at the saphenous opening, about 4 cm below and lateral to the pubic tubercle • ORDER at the inguinal ligament, LATERAL to MEDIAL — NAVY: Nerve, Artery, Vein, Y-fronts (the empty space of the femoral canal, with lymphatics) • Note the femoral NERVE is OUTSIDE the femoral sheath, lying on iliacus deep to the fascia iliaca — a favourite trap
Which muscles are attached to the iliotibial tract?Two, and between them the tract is really a conjoint tendon. • TENSOR FASCIAE LATAE — origin: the outer lip of the iliac crest between the ASIS and the iliac tubercle. It inserts into the ANTERIOR aspect of the tract about a third of the way down the thigh. Nerve: SUPERIOR GLUTEAL (L4, L5, S1) • GLUTEUS MAXIMUS — its superficial and upper fibres, about THREE-QUARTERS of the whole muscle, insert into the POSTERIOR aspect of the tract. Only the deeper, lower quarter reaches bone, at the gluteal tuberosity of the femur. Nerve: INFERIOR GLUTEAL (L5, S1, S2) • Some texts also describe a contribution from a slip of vastus lateralis and from the lateral intermuscular septum, which is attached to the deep surface of the tract • So the two muscles pull on the tract from in front and from behind, and their combined line of pull is converted into a single longitudinal force running down the lateral side of the thigh • DISTAL ATTACHMENT: chiefly GERDY'S TUBERCLE on the anterolateral condyle of the tibia, with additional fibres to the LATERAL FEMORAL EPICONDYLE (the Kaplan fibres, which anchor it and make it the pivot for the snapping in ITB syndrome) and to the patella as the iliopatellar band • CLINICAL: because both muscles are abductors, the tract is tensioned exactly when you stand on one leg — which is what its tension-band function requires
What is the function of the iliotibial tract?Four things, and the first is the one that earns the mark. • 1. IT IS A TENSION BAND. When you stand on one leg the body weight acting through the femoral head puts a large BENDING moment on the femur — compression along its medial side and TENSION along its lateral side. The iliotibial tract, tensioned by tensor fasciae latae and gluteus maximus, takes up that lateral tensile force and converts it into compression. Bone tolerates compression far better than tension, so the bending stress on the shaft falls dramatically — which is why the femur can be as slender as it is • 2. LATERAL STABILISER OF THE KNEE. It is a primary ANTEROLATERAL restraint, resisting varus and internal rotation of the tibia. Its relationship to the knee axis changes with flexion: beyond about 30 degrees it lies BEHIND the axis and assists flexion; below 30 degrees it lies IN FRONT and assists extension. It is that transition, as it flicks across the lateral femoral epicondyle, that produces both the PIVOT SHIFT in an ACL-deficient knee and the pain of iliotibial band syndrome • 3. It helps MAINTAIN THE EXTENDED KNEE in relaxed standing, so quadriceps can switch off — part of why standing at ease costs so little energy • 4. Through tensor fasciae latae it ASSISTS ABDUCTION, flexion and medial rotation of the hip, and it helps the abductors hold the pelvis level in the stance phase • It also gives attachment to the LATERAL INTERMUSCULAR SEPTUM, forming part of the boundary between the anterior and posterior compartments of the thigh • CLINICAL: ITB friction syndrome causes lateral knee pain in runners and cyclists at about 30 degrees of flexion, with a positive Ober's test for tightness. A SEGOND FRACTURE, avulsion of the anterolateral tibial rim, is pathognomonic of an ACL rupture. Strips of the tract are used for lateral extra-articular tenodesis and for ligament reconstruction
What is the name of the fascial compartment medial to the femoral vein, and what are its components?The FEMORAL CANAL — the most MEDIAL of the three compartments of the FEMORAL SHEATH. • The FEMORAL SHEATH is a funnel-shaped prolongation of the abdominal fascia carried down behind the inguinal ligament: TRANSVERSALIS fascia forms its anterior wall and FASCIA ILIACA its posterior wall. Two fibrous septa divide it into three compartments • LATERAL compartment — the femoral ARTERY, and the femoral branch of the genitofemoral nerve • INTERMEDIATE compartment — the femoral VEIN • MEDIAL compartment — the FEMORAL CANAL • The femoral NERVE is NOT in the sheath. It lies OUTSIDE it, lateral to the artery, on iliacus and deep to the fascia iliaca. Say this — it is a very common question • CONTENTS of the femoral canal: loose areolar and fatty connective tissue; efferent LYMPHATIC VESSELS from the lower limb and perineum; and CLOQUET'S NODE, also called Rosenmuller's node, the most superior deep inguinal lymph node • The canal is about 1.25 to 2 cm long and cone-shaped, with its base — the FEMORAL RING — above, closed by a condensation of extraperitoneal fat called the femoral septum • WHY IT EXISTS: it is a dead space that allows the femoral VEIN to DISTEND when venous return increases, during exercise or a Valsalva, and it carries the lymphatic drainage of the limb up to the external iliac nodes • CLINICAL: it is the route taken by a FEMORAL HERNIA. Because the ring is narrow and three of its four borders are rigid, femoral hernias STRANGULATE in up to 40 percent — the highest of any groin hernia. They are commoner in women because of the wider pelvis, and they present BELOW and LATERAL to the pubic tubercle
What is the function of the rectus femoris muscle?It has TWO functions, because it is the only head of quadriceps that crosses TWO joints. • EXTENDS THE KNEE — with the three vasti, through the quadriceps tendon, the patella and the patellar ligament to the tibial tuberosity • FLEXES THE HIP — because it arises above the joint, by a STRAIGHT HEAD from the ANTERIOR INFERIOR ILIAC SPINE and a REFLECTED HEAD from the groove above the acetabular rim • Being biarticular, its efficiency depends on the position of the other joint: it is a WEAK knee extensor when the hip is already flexed, because it is slackened, and a weak hip flexor when the knee is flexed. That is ACTIVE INSUFFICIENCY, and it is why you cannot kick powerfully from a fully flexed hip • It is BIPENNATE, unlike the vasti, so it has a large physiological cross-sectional area and generates high force over a short range — built for power rather than excursion • NERVE: femoral nerve (L2, L3, L4). It is the muscle of the KNEE JERK, root value L3 and L4 • CLINICAL: it is the most commonly strained of the quadriceps, typically at the musculotendinous junction, in sprinting and kicking; the reflected head is often the site of a proximal tear • AVULSION OF THE AIIS occurs in adolescent footballers kicking a ball, and is the counterpart of ASIS avulsion by sartorius at a sprint start • ELY'S TEST — with the patient prone, passively flex the knee; if the ipsilateral hip rises off the couch, rectus femoris is tight • It is used as a pedicled or free muscle flap, and rectus femoris transfer is performed for stiff-knee gait in cerebral palsy
In an injury of the common peroneal nerve, which compartment will be affected and what is the sensory loss?BOTH the ANTERIOR and the LATERAL compartments of the leg, because the nerve divides into its deep and superficial branches at the neck of the fibula, distal to the usual site of injury. • THE NERVE: common peroneal (fibular) nerve, L4, L5, S1, S2 — the smaller terminal branch of the sciatic. It leaves the popliteal fossa along the medial border of BICEPS FEMORIS, crosses the lateral head of gastrocnemius, and winds round the NECK OF THE FIBULA, where it is subcutaneous and tethered. It is the most commonly injured nerve in the lower limb • ANTERIOR COMPARTMENT, via the DEEP peroneal nerve: tibialis anterior, extensor hallucis longus, extensor digitorum longus and peroneus tertius. Loss gives FOOT DROP — no dorsiflexion, no toe extension, and a high-stepping gait • LATERAL COMPARTMENT, via the SUPERFICIAL peroneal nerve: peroneus longus and brevis. Loss gives no EVERSION, so the foot falls into equinoVARUS rather than simply dropping • SENSORY LOSS — be precise, because this is where marks are won • DEEP peroneal supplies ONLY the FIRST DORSAL WEB SPACE, a small triangle between the great and second toes. That is its autonomous zone • SUPERFICIAL peroneal supplies the ANTEROLATERAL aspect of the lower leg and most of the DORSUM of the foot • The LATERAL SURAL CUTANEOUS nerve, given off in the popliteal fossa, supplies the upper lateral calf and is lost in a lesion above the fibular neck • CAUSES: fracture of the fibular neck, a tight plaster or knee brace, prolonged squatting or leg crossing, lithotomy or prolonged bed positioning, knee dislocation (in up to a quarter), high tibial osteotomy, and a ganglion of the superior tibiofibular joint • DIFFERENTIAL: an L5 radiculopathy looks similar, but L5 ALSO weakens hip abduction and foot INVERSION (tibialis posterior, a tibial-nerve muscle). Testing INVERSION separates them — it is preserved in a common peroneal palsy • MANAGEMENT: ankle-foot orthosis; most compressive palsies recover in 3 to 6 months. Explore an open injury, or a deficit that appears after reduction
A patient has loss of sensation over the anterolateral aspect of the leg and cannot extend the great toe. Which nerve is injured?The COMMON PERONEAL (fibular) NERVE, at the neck of the fibula — and you should say WHY, because the two halves of the question point to two different branches. • Inability to extend the great toe means a weak EXTENSOR HALLUCIS LONGUS, which is supplied by the DEEP peroneal nerve • Loss of sensation over the ANTEROLATERAL LEG is the territory of the SUPERFICIAL peroneal nerve. The deep peroneal nerve's own sensory territory is ONLY the first dorsal web space, a patch a couple of centimetres across • Since BOTH branches are affected, the lesion must lie AT or PROXIMAL to the point where they divide — that is, the COMMON PERONEAL nerve as it winds around the fibular neck • If you were to name a single nerve, name the common peroneal. If the examiner presses on which branch does what, give the split above • Examine to confirm: test dorsiflexion and toe extension (deep), EVERSION (superficial), and INVERSION (tibialis posterior, tibial nerve — should be NORMAL). Check the ankle jerk (S1) — normal. Look for a fibular neck fracture, a tight cast, or a history of prolonged squatting or leg crossing • THE DIFFERENTIAL IS AN L5 RADICULOPATHY, and it is the answer the examiner may be fishing for. L5 also weakens extensor hallucis longus and numbs the lateral leg and dorsum of the foot. Separate them by: L5 additionally weakens HIP ABDUCTION (gluteus medius) and foot INVERSION, and is accompanied by back pain with a positive straight leg raise. A peripheral common peroneal lesion spares both, and there is often a Tinel's sign at the fibular neck
What are the boundaries of the femoral canal?Give the boundaries of the FEMORAL RING, which is the base — the abdominal opening — of the canal. • ANTERIOR — the INGUINAL LIGAMENT • POSTERIOR — the PECTINEAL LIGAMENT (of Cooper), the superior pubic ramus, and the fascia over pectineus • MEDIAL — the sharp, crescentic FREE EDGE OF THE LACUNAR LIGAMENT (of Gimbernat) • LATERAL — the FEMORAL VEIN, separated from the canal by a thin fibrous septum • The ring is closed above by the FEMORAL SEPTUM, a condensation of extraperitoneal fat covered by parietal peritoneum • The CANAL itself, running down from the ring, is bounded ANTERIORLY by the fascia lata, POSTERIORLY by the fascia over pectineus, LATERALLY by the femoral vein, and MEDIALLY by the lacunar ligament and the junction of the fascia lata with the pectineal fascia. It is 1.25 to 2 cm long • CONTENTS: fat, lymphatics and Cloquet's node • WHY IT MATTERS: three of the four borders are rigid ligament or bone, and the fourth is a vein, so a femoral hernia entering the ring cannot expand. This is why the STRANGULATION RATE is up to 40 percent and why a femoral hernia is an urgent operation, not a watchful-waiting one • IF YOU MUST ENLARGE THE RING to reduce strangulated bowel, divide the LACUNAR LIGAMENT medially — but beware the CORONA MORTIS, an abnormal obturator artery arising from the inferior epigastric instead of the internal iliac in 25 to 30 percent of people, which arches over the lacunar ligament. Dividing it blindly causes brisk retropubic bleeding that retracts out of reach. Safer alternatives are to divide the inguinal ligament, or to approach from above • REPAIRS: Lockwood low approach for an elective repair; Lotheissen trans-inguinal; and McEVEDY high extraperitoneal approach, which is the one of choice in an emergency because it gives access for bowel resection
What are the boundaries of the femoral triangle?A triangle with its base above, formed by three muscular and ligamentous edges, plus a roof and a floor. • BASE, superiorly — the INGUINAL LIGAMENT • LATERAL border — the medial border of SARTORIUS • MEDIAL border — the medial border of ADDUCTOR LONGUS • APEX, inferiorly — where sartorius crosses over adductor longus. Beyond the apex the neurovascular bundle continues into the ADDUCTOR (subsartorial or Hunter's) CANAL • ROOF — from superficial to deep: skin, superficial fascia containing the superficial inguinal lymph nodes and the great saphenous vein, and the FASCIA LATA, which is pierced by the SAPHENOUS OPENING (fossa ovalis) about 4 cm below and lateral to the pubic tubercle. The opening is covered by the CRIBRIFORM FASCIA and transmits the great saphenous vein • FLOOR — a gutter formed, from LATERAL to MEDIAL, by ILIACUS, PSOAS MAJOR, PECTINEUS and ADDUCTOR LONGUS • CONTENTS, lateral to medial — NAVY: femoral NERVE (outside the femoral sheath, on iliacus), femoral ARTERY, femoral VEIN, and the empty space of the femoral canal with its lymphatics. Also within it: the femoral branch of the genitofemoral nerve, the origin of PROFUNDA FEMORIS about 4 cm below the inguinal ligament, the deep inguinal lymph nodes, and the great saphenous termination • CLINICAL: the femoral artery is punctured here for coronary and peripheral angiography — enter OVER THE FEMORAL HEAD so the vessel can be compressed against bone afterwards; puncture below the bifurcation risks a pseudoaneurysm, above the inguinal ligament risks a retroperitoneal bleed • A femoral nerve block is placed just lateral to the arterial pulse below the ligament • A psoas abscess tracks down the psoas sheath and points in the triangle • The triangle is also where you feel for the femoral pulse and examine for femoral hernia and lymphadenopathy
Identify the sciatic nerve in this prosection. What are its root values?The SCIATIC NERVE — root values L4, L5, S1, S2 and S3. • It is the largest nerve in the body, about 2 cm wide where it leaves the pelvis. Identify it as the broad, flat, cord-like structure emerging beneath the lower border of PIRIFORMIS and running downwards deep to gluteus maximus • It is really TWO nerves in one sheath — the TIBIAL division (anterior divisions of L4 to S3) and the COMMON PERONEAL division (posterior divisions of L4 to S2). They separate at about the apex of the popliteal fossa, though the level varies widely; in 10 to 15 percent the common peroneal division pierces piriformis or passes above it • COURSE: leaves the pelvis through the GREATER SCIATIC FORAMEN, BELOW PIRIFORMIS. In the gluteal region it lies on, from above downwards, the superior gemellus, the tendon of obturator internus, the inferior gemellus and QUADRATUS FEMORIS. It descends midway between the ischial tuberosity and the greater trochanter, then passes deep to the long head of biceps femoris into the back of the thigh • BRANCHES in the thigh: the hamstrings and the ischiocondylar part of adductor magnus from the TIBIAL division; the short head of biceps femoris from the COMMON PERONEAL division. Then everything below the knee • It has NO cutaneous branches in the thigh — the skin there is supplied by the posterior cutaneous nerve of the thigh, a separate branch of the sacral plexus • CLINICAL: injured in posterior hip dislocation and in up to 1 percent of total hip replacements through the posterior approach. The COMMON PERONEAL division is the more vulnerable — it is more lateral, has less protective connective tissue, and is tethered distally at the fibular neck, so it takes the stretch. Also injured by an intramuscular injection into the wrong quadrant of the buttock, and compressed in piriformis syndrome
What are the surface markings in the gluteal region?Give the safe injection site and the sciatic nerve — they are two sides of the same anatomy. • THE INJECTION SITE: divide the buttock into quadrants with a vertical and a horizontal line through its midpoint, and inject into the UPPER OUTER (superolateral) QUADRANT. This avoids the sciatic nerve, which lies in the lower medial quadrant, and the superior gluteal vessels. The alternative and now often preferred VENTROGLUTEAL site is located by placing your palm on the greater trochanter with the index finger on the ASIS and the middle finger spread towards the iliac crest, and injecting into the V between them — it targets gluteus medius and is further from any nerve • THE SCIATIC NERVE: it emerges from the pelvis at a point ONE-THIRD of the way down a line from the POSTERIOR SUPERIOR ILIAC SPINE to the ISCHIAL TUBEROSITY. It then curves laterally and descends at the MIDPOINT of a line between the ISCHIAL TUBEROSITY and the GREATER TROCHANTER, continuing down the midline of the back of the thigh to the apex of the popliteal fossa • OTHER LANDMARKS: the PSIS lies beneath the dimple of Venus, at the level of S2, marking the middle of the sacroiliac joint and the lower limit of the dural sac • The GREATER TROCHANTER is the highest palpable bony point laterally, lying at the level of the pubic tubercle and of the centre of the femoral head • The ISCHIAL TUBEROSITY becomes palpable when the hip is FLEXED, because gluteus maximus slides off it — the sit bone • The SUPERIOR GLUTEAL ARTERY emerges at the junction of the upper and middle thirds of a line from the PSIS to the top of the greater trochanter; the INFERIOR GLUTEAL ARTERY at the junction of the upper and middle thirds of a line from the PSIS to the ischial tuberosity
Identify gluteus medius in this prosection. Describe its origin, insertion, nerve supply and root values.It is the fan-shaped muscle lying DEEP to gluteus maximus, running from the outer surface of the ilium down to the greater trochanter. Find it by reflecting gluteus maximus; its anterior part is covered only by tensor fasciae latae and the gluteal aponeurosis, and gluteus minimus lies deep to it. • ORIGIN: the OUTER SURFACE OF THE ILIUM, between the POSTERIOR and ANTERIOR GLUTEAL LINES, and from the gluteal aponeurosis covering it • INSERTION: an oblique ridge on the LATERAL SURFACE OF THE GREATER TROCHANTER of the femur • NERVE SUPPLY: the SUPERIOR GLUTEAL NERVE, root values L4, L5 and S1 • The nerve leaves the pelvis through the greater sciatic foramen ABOVE PIRIFORMIS — the only structure to do so — accompanied by the superior gluteal artery, and runs forwards in the plane BETWEEN gluteus medius and gluteus minimus, which it supplies, before ending in tensor fasciae latae • BLOOD SUPPLY: the superior gluteal artery, a branch of the posterior division of the internal iliac • ACTIONS: with gluteus minimus it ABDUCTS the hip; its ANTERIOR fibres medially rotate and flex, its POSTERIOR fibres laterally rotate and extend. But its principal role is in the stance phase of gait • WHERE IT SITS IN THE DISSECTION: the superior gluteal neurovascular bundle emerging between medius and minimus is the reliable way to confirm you have the right muscle, and the plane between them is the plane used surgically • CLINICAL: the superior gluteal nerve is at risk in the LATERAL (Hardinge) APPROACH to the hip if the abductor split is carried more than 5 cm proximal to the tip of the greater trochanter, and from an intramuscular injection placed too low and medial
What is the action of gluteus medius during walking?Its job in gait is NOT to abduct the leg into the air — it is to stop the pelvis falling. • During the STANCE PHASE, when the opposite foot has left the ground, the whole weight of the body and the swinging limb acts on the far side of the pelvis and tries to tilt it downwards. The gluteus medius and minimus of the WEIGHT-BEARING side contract to hold the pelvis LEVEL, or even lift it very slightly, so the swinging leg clears the ground • In mechanical terms they ABDUCT THE TRUNK ON A FIXED FEMUR — the origin becomes the moving end • They also work ECCENTRICALLY at heel strike to control the rate of pelvic drop, and the anterior fibres produce the MEDIAL ROTATION that swings the pelvis forward over the planted leg • The forces are large: because the abductor lever arm is short compared with the distance to the body's centre of gravity, the abductors must generate a force of roughly two to three times body weight, and the hip joint reaction force in single-leg stance is around three times body weight. This is the reason a patient with a painful hip is told to carry a stick in the OPPOSITE hand — it reduces the abductor force required and so unloads the joint • IF THEY FAIL, the pelvis drops on the unsupported side — a positive Trendelenburg sign — and the patient compensates by throwing the trunk over the affected hip, the Trendelenburg lurch, which moves the centre of gravity closer to the hip and reduces the abductor force needed • This lever arm is why FEMORAL OFFSET is deliberately restored during a total hip replacement: too little offset and the abductors are slack and inefficient, giving a limp and a higher dislocation rate
What is the clinical test to assess gluteus medius, how is it performed, and what are the other causes of a positive Trendelenburg test?THE TRENDELENBURG TEST. • TECHNIQUE: expose the pelvis and stand BEHIND the patient. Place your hands on the iliac crests, or have the patient rest their hands on your outstretched hands for balance, which is how Trendelenburg described it • Ask the patient to stand on one leg, lifting the opposite knee to about 90 degrees. Then repeat on the other side • WATCH THE PELVIS ON THE UNSUPPORTED (lifted) SIDE • NEGATIVE, normal: the pelvis on the lifted side RISES or stays level, because the abductors of the standing leg are working • POSITIVE: the pelvis on the lifted, unsupported side DROPS. The abnormality is on the side being STOOD ON — get this the right way round • Hold the position for 30 seconds; a drop appearing late is a DELAYED Trendelenburg and indicates fatigable weakness • If the patient throws the trunk over the standing hip to stay upright, that is the Trendelenburg LURCH and the test is still positive — it is a compensation, not a negative • OTHER CAUSES OF A POSITIVE TEST — the mark is in classifying them, because it is not simply a weak muscle • NERVE: superior gluteal nerve palsy — an intramuscular injection in the wrong quadrant, the lateral approach to the hip, iatrogenic injury at total hip replacement. Also L5 radiculopathy and poliomyelitis • MUSCLE: abductor avulsion or detachment after surgery, greater trochanteric fracture or non-union, gluteal tendinopathy and tears, and myopathies such as muscular dystrophy • PAIN or an IRRITABLE JOINT: any painful hip gives an antalgic positive test because the patient refuses to load it — osteoarthritis, septic arthritis, inflammatory arthritis • UNSTABLE FULCRUM: developmental dysplasia of the hip, hip dislocation, after an excision arthroplasty • ABNORMAL LEVER ARM, where the muscle is normal but mechanically disadvantaged: fractured neck of femur, COXA VARA, slipped upper femoral epiphysis, malunion, and a total hip replacement with inadequate offset. Shortening the distance between origin and insertion makes a healthy muscle inefficient • So the answer is NERVE, MUSCLE, PAIN, or FULCRUM — say it in those four groups
Name the hamstring muscles. What are the actions of each alone, and of all together?Three muscles, plus part of a fourth, all arising from the ISCHIAL TUBEROSITY and all supplied by the TIBIAL division of the sciatic nerve — those two features are the definition of a hamstring. • BICEPS FEMORIS — LONG head from the ischial tuberosity, as a conjoint tendon with semitendinosus; SHORT head from the linea aspera and the lateral supracondylar line. Inserts into the HEAD OF THE FIBULA, splitting around the fibular collateral ligament. Long head: TIBIAL division. SHORT head: COMMON PERONEAL division — so strictly the short head is NOT a true hamstring, since it neither crosses the hip nor shares the nerve • SEMITENDINOSUS — ischial tuberosity; inserts on the upper MEDIAL surface of the tibia as part of the PES ANSERINUS with sartorius and gracilis. Mnemonic for the pes, front to back: Say Grace before Tea — Sartorius, Gracilis, semiTendinosus. Tibial division • SEMIMEMBRANOSUS — a separate, deeper and more lateral facet on the ischial tuberosity; inserts mainly into the groove on the posterior aspect of the MEDIAL TIBIAL CONDYLE, with expansions to the OBLIQUE POPLITEAL LIGAMENT, the popliteus fascia and the medial meniscus. Tibial division • The ISCHIOCONDYLAR part of ADDUCTOR MAGNUS, from the ischial tuberosity to the adductor tubercle, supplied by the tibial division — included by definition • ACTIONS EACH ALONE, with the knee flexed: BICEPS FEMORIS flexes the knee and LATERALLY rotates the leg; SEMITENDINOSUS and SEMIMEMBRANOSUS flex the knee and MEDIALLY rotate it. Acting at the hip, the long head of biceps, semitendinosus and semimembranosus all EXTEND it • Semimembranosus additionally retracts the MEDIAL MENISCUS during flexion, protecting it from being crushed, and tightens the oblique popliteal ligament to reinforce the posterior capsule • ALL TOGETHER: they EXTEND THE HIP and FLEX THE KNEE. Because they span two joints they cannot shorten fully over both at once — that PASSIVE INSUFFICIENCY is what limits the straight leg raise • IN GAIT: they act ECCENTRICALLY in terminal swing to decelerate the forward-swinging leg, then concentrically to extend the hip at heel strike. This eccentric phase is when they tear • CLINICAL: hamstring strain is the commonest muscle injury in sport, usually at the biceps femoris musculotendinous junction. Proximal avulsion off the ischial tuberosity needs repair if all three tendons are involved with more than 2 cm retraction. Ischial APOPHYSEAL avulsion occurs in adolescents. Semitendinosus and gracilis are harvested for ACL reconstruction. Tight hamstrings limit straight leg raise and cause a false-positive sciatic stretch test
Identify all the structures on this posterior prosection of the knee.Work in layers, and give the boundaries before the contents. • SUPERFICIAL: skin, then superficial fascia containing the SMALL (short) SAPHENOUS VEIN, which pierces the deep fascia to drain into the popliteal vein, and the SURAL NERVE, formed from the medial sural cutaneous nerve of the tibial nerve joined by the sural communicating branch of the common peroneal • POPLITEAL FASCIA — the tough deep fascia roofing the fossa, continuous with the fascia lata above and the deep fascia of the leg below, and pierced by the small saphenous vein • BOUNDARIES of the diamond: SUPEROLATERAL — biceps femoris; SUPEROMEDIAL — semimembranosus, with semitendinosus overlying it; INFEROLATERAL — the lateral head of gastrocnemius with plantaris; INFEROMEDIAL — the medial head of gastrocnemius • FLOOR, from above down: the popliteal surface of the FEMUR, the posterior capsule of the knee joint reinforced by the OBLIQUE POPLITEAL LIGAMENT (an expansion of the semimembranosus tendon), and POPLITEUS covered by its fascia • CONTENTS, from SUPERFICIAL to DEEP — and this is the order to recite because it is the reverse of the anterior thigh: TIBIAL NERVE most superficial, then the POPLITEAL VEIN, then the POPLITEAL ARTERY deepest, lying directly on the capsule and the popliteal surface of the femur • The COMMON PERONEAL NERVE is NOT in the middle of the fossa — it runs along the medial border of BICEPS FEMORIS, forming part of the superolateral boundary, and leaves to wind round the fibular neck • GENICULAR VESSELS: the superior medial, superior lateral, middle, inferior medial and inferior lateral genicular arteries arising from the popliteal artery and forming the anastomosis around the knee. The middle genicular pierces the capsule to supply the cruciates • POPLITEAL LYMPH NODES, about six, embedded in the fat around the vessels • Also visible: the head of the fibula, the fibular collateral ligament, the tendon of popliteus emerging from the joint, and the posterior cruciate ligament through the capsule
What are the structures in the popliteal fossa?Contents, from SUPERFICIAL to DEEP — say them in that order and the arrangement answers itself. • TIBIAL NERVE — the most SUPERFICIAL and the most midline. It is the larger terminal branch of the sciatic, enters at the apex and leaves at the lower angle deep to the fibrous arch of soleus • POPLITEAL VEIN — deep to the nerve, formed by the union of the venae comitantes at the lower border of popliteus. It receives the small saphenous vein • POPLITEAL ARTERY — the DEEPEST structure, lying directly on the popliteal surface of the femur and the posterior capsule. It is the continuation of the femoral artery from the adductor hiatus, and it ends at the lower border of popliteus by dividing into the anterior and posterior tibial arteries • Mnemonic from the skin inwards: Nerve, Vein, Artery • COMMON PERONEAL NERVE — running along the medial border of biceps femoris, part of the superolateral boundary rather than the centre of the fossa • BRANCHES: five GENICULAR arteries — superior medial, superior lateral, middle, inferior medial and inferior lateral — plus sural arteries to gastrocnemius. The tibial nerve gives the medial sural cutaneous nerve and branches to gastrocnemius, soleus, plantaris and popliteus; the common peroneal gives the lateral sural cutaneous nerve and articular branches • POPLITEAL LYMPH NODES, about six, and a quantity of FAT which fills the fossa • CLINICAL CONSEQUENCES OF THE DEPTH OF THE ARTERY: it is the hardest peripheral pulse to feel — flex the knee to about 30 degrees to relax the fascia and press deeply with both hands. It is the commonest site of a peripheral ANEURYSM. And lying against bone with the fascia unyielding, it is the vessel injured in a supracondylar femoral fracture or a knee dislocation
Which structures are at risk in a supracondylar fracture of the femur?The POPLITEAL ARTERY above all — name it first. • THE MECHANISM: the distal fragment is pulled POSTERIORLY and into extension by the pull of GASTROCNEMIUS, which arises from the posterior aspect of the femoral condyles. The sharp proximal edge of that fragment is driven directly into the popliteal fossa • WHY THE ARTERY CANNOT ESCAPE: it is TETHERED at both ends — above, where it passes through the ADDUCTOR HIATUS in adductor magnus, and below, at the fibrous arch of SOLEUS. Fixed at both ends, it cannot be pushed aside. This is the exact counterpart of the brachial artery in a supracondylar humeral fracture • ALSO AT RISK: the POPLITEAL VEIN, the TIBIAL NERVE and the COMMON PERONEAL NERVE • CONSEQUENCES: acute limb ischaemia from transection or compression; an INTIMAL TEAR with delayed thrombosis, which means a normal pulse at presentation does NOT exclude arterial injury and the limb must be re-examined repeatedly; and COMPARTMENT SYNDROME of the leg, particularly after reperfusion • ASSESSMENT: document the distal neurovascular status BEFORE and AFTER every manipulation. Reduce and splint the limb, then reassess — reduction alone often restores flow. Measure the ANKLE-BRACHIAL PRESSURE INDEX; below 0.9 warrants CT angiography or on-table angiography • MANAGEMENT: hard signs of vascular injury — absent pulses, an expanding haematoma, a bruit or thrill, active bleeding — mandate immediate exploration without waiting for imaging. VASCULAR REPAIR TAKES PRIORITY: a temporary intraluminal shunt first, then skeletal stabilisation, then definitive repair or vein graft. Consider prophylactic four-compartment fasciotomy if the ischaemic time exceeds four to six hours • The injury occurs in two very different populations: low-energy fractures in osteoporotic elderly patients, often PERIPROSTHETIC above a total knee replacement, and high-energy fractures in young patients from dashboard injuries
What are the causes of a swelling in the popliteal fossa, classified by structure of origin?Classify by tissue of origin — the structure of the answer is the mark. • SKIN AND SUBCUTANEOUS TISSUE: sebaceous cyst, lipoma, abscess • BURSA AND SYNOVIUM: BAKER'S (popliteal) CYST — distension of the semimembranosus/medial gastrocnemius bursa, which communicates with the knee joint through a one-way valve. In ADULTS it is almost always SECONDARY to intra-articular pathology — osteoarthritis, a meniscal tear, or rheumatoid arthritis — so treat the joint, not the cyst. In children it is usually primary and resolves. Rupture mimics a DVT. Also semimembranosus bursitis, and a distended posterior joint pouch • ARTERY: POPLITEAL ANEURYSM — the commonest peripheral arterial aneurysm. 50 percent are BILATERAL and 40 to 50 percent are associated with an abdominal aortic aneurysm, so examine both legs and the abdomen. The danger is not rupture but DISTAL EMBOLISATION and acute limb ischaemia. A PULSATILE, EXPANSILE swelling is a popliteal aneurysm until proven otherwise, and you must never aspirate it. Also false aneurysm and popliteal artery entrapment syndrome • VEIN: varicose veins, a saphena varix at the small saphenous termination, deep vein thrombosis • NERVE: schwannoma or neurofibroma of the tibial or common peroneal nerve; and a GANGLION of the superior tibiofibular joint tracking along the common peroneal nerve, which can present with a foot drop • BONE: OSTEOCHONDROMA of the distal femur — the commonest benign bone tumour and a classic hard, fixed popliteal lump; osteosarcoma of the distal femur, which has its peak incidence exactly here; and fracture haematoma • MUSCLE AND SOFT TISSUE: soft tissue sarcoma, haematoma, and a tear of the medial head of gastrocnemius (tennis leg) • LYMPH NODE: popliteal lymphadenopathy, from infection of the HEEL or the LATERAL foot, or metastatic melanoma from the same territory • INVESTIGATION: ULTRASOUND first — it separates cystic from solid, and Doppler identifies a pulsatile lesion immediately. MRI for any solid lesion. Never aspirate before imaging
What is the drainage of the popliteal lymph nodes?About SIX nodes, embedded in the fat of the popliteal fossa around the popliteal vessels. • WHAT DRAINS INTO THEM (afferents): • the SUPERFICIAL tissues of the LATERAL side of the leg and foot, and the HEEL, following the SMALL SAPHENOUS VEIN • the DEEP structures of the leg, via lymphatics accompanying the anterior tibial, posterior tibial and peroneal vessels • the KNEE JOINT itself • WHERE THEY DRAIN TO (efferents): upwards along the FEMORAL VESSELS to the DEEP INGUINAL NODES; from there through the FEMORAL CANAL, via Cloquet's node, to the EXTERNAL ILIAC nodes; then the common iliac and para-aortic (lumbar) nodes; then the cisterna chyli and the THORACIC DUCT, ending in the left brachiocephalic vein • Some deep lymphatic trunks bypass the popliteal group altogether and pass straight to the deep inguinal nodes • THE CLINICAL POINT, which is why the question is asked: the foot has a SPLIT drainage. The HEEL and the LATERAL side of the foot and leg drain first to the POPLITEAL nodes, along the small saphenous vein. The rest of the foot and the MEDIAL side of the leg drain along the GREAT saphenous vein DIRECTLY to the SUPERFICIAL INGUINAL nodes, bypassing the popliteal group entirely • So a malignant melanoma or a spreading infection on the LATERAL HEEL can have popliteal nodal spread with a completely normal groin. You must examine the popliteal fossa in any patient with a lesion of the heel or lateral foot, and popliteal nodes should be included in the sentinel node mapping • They are difficult to palpate because they lie deep to the tough popliteal fascia — examine with the knee FLEXED to about 30 degrees to relax it, using the fingers of both hands from behind
A patient arrives after a road traffic accident with a neck and shoulder injury. What is the suspected injury?A BRACHIAL PLEXUS TRACTION INJURY — but start with the primary survey, and give a structured differential before you commit. • FIRST: this is an RTA, so ATLS. Primary survey, cervical spine immobilised until cleared, and exclude head, chest and abdominal injury. A first rib fracture or a widened mediastinum on the chest film means aortic injury until proven otherwise • THE DIFFERENTIAL, by tissue • BONE: cervical spine fracture or dislocation; clavicle fracture; SCAPULAR fracture, which is a marker of very high energy and mandates a search for associated injuries; proximal humeral fracture; first rib fracture • JOINT: anterior shoulder dislocation, acromioclavicular disruption, and POSTERIOR sternoclavicular dislocation, which can compress the trachea and great vessels • NERVE: brachial plexus injury, isolated axillary nerve injury, cervical cord or root injury, and long thoracic or spinal accessory nerve palsy • VESSEL: subclavian or axillary artery injury, particularly with a first rib or badly displaced clavicle fracture • SOFT TISSUE: rotator cuff tear, trapezius and sternocleidomastoid strain • THE MECHANISM for the plexus: forcible DEPRESSION OF THE SHOULDER with lateral flexion of the neck AWAY from it widens the head-to-shoulder angle and puts traction on the UPPER roots, C5 and C6. Forcible HYPERABDUCTION of the arm instead pulls on the LOWER roots, C8 and T1 • ASSESSMENT: a full motor, sensory and reflex examination of the whole limb, the vascular status, and specifically look for HORNER'S SYNDROME and for WINGING of the scapula • PREGANGLIONIC versus POSTGANGLIONIC is the question that determines treatment. Preganglionic (root avulsion) is suggested by Horner's syndrome, winged scapula, an elevated hemidiaphragm on the chest film (phrenic nerve, C3, 4, 5), severe burning pain in an anaesthetic limb, and preserved sensory nerve conduction despite clinical anaesthesia. Preganglionic lesions do not recover and need nerve transfers; postganglionic ruptures can be grafted • IMAGING: chest and cervical spine films, CT of the shoulder girdle, and CT myelography or MRI at three to four weeks looking for pseudomeningoceles
Which is the commonest trunk to be injured?The UPPER TRUNK, formed by C5 and C6. • WHY: the commonest mechanism is forcible widening of the angle between the head and the shoulder — a motorcyclist thrown over the handlebars, or a fall landing on the point of the shoulder. That vector puts maximal traction on the uppermost roots • C5 and C6 also take the most direct, vertical course from the foramina and are the least protected by surrounding structures • There is a second, more useful reason. The C5 and C6 roots are relatively well anchored to their transverse processes by fascial slips, so under traction they tend to RUPTURE distal to the ganglion — a POSTGANGLIONIC injury, which can be grafted. C8 and T1 have much weaker attachments and tend to AVULSE from the cord — a PREGANGLIONIC injury, which cannot be repaired directly and needs a nerve transfer. So the commonest injury is also the more reconstructable one • ERB'S POINT is the anatomical vulnerable spot: the junction where C5 and C6 unite to form the upper trunk, about 2 to 3 cm above the clavicle at the posterior border of sternocleidomastoid. Six nerves meet at that point • CONSEQUENCE: upper trunk injury equals ERB'S PALSY, which is both the commonest adult traction injury and the commonest obstetric brachial plexus palsy, where the mechanism is shoulder dystocia in a large baby
C5 will exit between which two vertebrae?Between C4 and C5 — through the C4/C5 intervertebral foramen, ABOVE the C5 vertebra. • THE RULE: in the CERVICAL spine a nerve root exits ABOVE its correspondingly numbered vertebra. C5 exits above C5, C6 above C6, and so on • This is possible because there are EIGHT cervical nerves but only SEVEN cervical vertebrae. C1 exits between the occiput and the atlas, and C8 exits between C7 and T1 — that is where the numbering switches over • From T1 downwards the rule reverses: a root exits BELOW its numbered vertebra, so T1 exits through the T1/T2 foramen • CLINICAL: this is why a cervical disc prolapse at C4/5 compresses the C5 root and a prolapse at C5/6 compresses C6 — the root exiting at that level. Contrast this with the LUMBAR spine, where a paracentral L4/5 disc typically spares the exiting L4 root and compresses the TRAVERSING L5 root instead. Getting the cervical rule right is what lets you predict the level from the clinical findings • So a patient with weak deltoid, a weak biceps jerk and numbness over the regimental badge area has a C5 radiculopathy from a C4/5 disc
Where do the roots of the brachial plexus arise from? Point at the vertebrae.From the ANTERIOR (ventral) RAMI of C5, C6, C7, C8 and T1 — point at the anterolateral aspect of the lower cervical spine and the first thoracic vertebra. • VARIANTS: a PREFIXED plexus takes an additional contribution from C4, a POSTFIXED plexus from T2. About a quarter of people have one or the other • Anatomically the roots emerge from the intervertebral foramina and pass BETWEEN SCALENUS ANTERIOR and SCALENUS MEDIUS, which arise from the anterior and posterior tubercles of the cervical transverse processes. That INTERSCALENE GROOVE is where an interscalene block is deposited, and it is the site of compression in neurogenic thoracic outlet syndrome • THE SEQUENCE: Roots become TRUNKS — upper (C5, C6), middle (C7), lower (C8, T1) — which split into anterior and posterior DIVISIONS behind the clavicle, which recombine as the lateral, posterior and medial CORDS around the axillary artery, which give the terminal BRANCHES. Mnemonic: Real Texans Drink Cold Beer • SURFACE MARKING, which is what to show on the actor: the plexus runs from the interscalene groove at the level of the CRICOID CARTILAGE — that is C6, the level of Chassaignac's tubercle, the anterior tubercle of the C6 transverse process — downwards and laterally to the MIDDLE THIRD OF THE CLAVICLE, then into the axilla • WHERE EACH PART LIES: roots and trunks in the POSTERIOR TRIANGLE of the neck; divisions BEHIND THE CLAVICLE; cords and branches in the AXILLA. A supraclavicular block targets the trunks, an infraclavicular block the cords • The roots also give branches before the trunks form: the dorsal scapular nerve from C5, the long thoracic nerve from C5, C6 and C7, and the contribution to the phrenic nerve from C5
What are the C5 and C6 cutaneous supplies on the body, and their reflexes?Give the dermatome and then the reflex for each, and be prepared to point at them on the model. • C5 DERMATOME — the skin over the LATERAL aspect of the upper arm: the REGIMENTAL BADGE area over the lower half of deltoid, extending down the lateral arm towards the elbow. Strictly the badge patch is the territory of the upper lateral cutaneous nerve of the arm, a branch of the AXILLARY nerve, which carries C5 and C6 • C5 REFLEX — the BICEPS JERK (C5, with a C6 contribution) • C6 DERMATOME — the LATERAL FOREARM, the THUMB and the index finger. The simple version: C6 is the thumb. Run your hand down the radial border of the forearm onto the thumb • C6 REFLEX — the SUPINATOR (brachioradialis) JERK, predominantly C6. The biceps jerk also carries C6 • FOR COMPLETENESS at the station: C7 is the MIDDLE FINGER, reflex the TRICEPS JERK. C8 is the LITTLE FINGER and the medial forearm, no reflex. T1 is the MEDIAL ARM above the elbow, no reflex. T2 is the axilla • MNEMONIC for the reflex levels: one-two buckle my shoe (S1, S2 ankle), three-four kick the door (L3, L4 knee), five-six pick up sticks (C5, C6 biceps and supinator), seven-eight shut the gate (C7, C8 triceps) • HOW TO DEMONSTRATE: touch the regimental badge for C5, the thumb for C6, the middle finger for C7, the little finger for C8, and the medial upper arm for T1 — then elicit the biceps, supinator and triceps jerks • THE CONCEPTUAL POINT the examiner may be after: a DERMATOME is a ROOT territory with a two to three segment OVERLAP, so a single root lesion rarely produces complete anaesthesia — only blunting. A PERIPHERAL NERVE territory is sharply demarcated with complete loss. That difference is exactly how you distinguish a root lesion from a nerve lesion at the bedside
Describe Erb's palsy and Klumpke's palsy.Two traction injuries at opposite ends of the plexus, with opposite mechanisms and opposite pictures. • ERB'S PALSY — UPPER TRUNK, C5 and C6, sometimes C7 • MECHANISM: forcible increase in the angle between the head and the shoulder. In adults a motorcycle accident or a fall onto the point of the shoulder; in neonates, SHOULDER DYSTOCIA during a difficult vaginal delivery of a large baby • MUSCLES LOST: deltoid and teres minor (axillary), supraspinatus and infraspinatus (suprascapular), biceps, brachialis and coracobrachialis (musculocutaneous), brachioradialis and supinator (radial). If the lesion is at root level, also rhomboids and serratus anterior • THE POSITION — the WAITER'S TIP: the arm hangs ADDUCTED, because deltoid and supraspinatus are out; MEDIALLY ROTATED, because infraspinatus and teres minor are out and subscapularis and pectoralis major are unopposed; the elbow EXTENDED, because biceps and brachialis are out; the forearm PRONATED, because supinator and biceps are out; and the wrist FLEXED • SENSORY: loss over the lateral arm and forearm, the C5 and C6 dermatomes • REFLEXES: biceps and supinator jerks lost; TRICEPS PRESERVED • THE HAND IS NORMAL — that is the key discriminator • KLUMPKE'S PALSY — LOWER TRUNK, C8 and T1 • MECHANISM: forcible ABDUCTION of the arm above the head — grabbing for a branch while falling, or a breech delivery with the arm extended above the head • MUSCLES LOST: ALL the intrinsic muscles of the hand, plus the long finger flexors • THE POSITION — the CLAW HAND, main en griffe: metacarpophalangeal joints HYPEREXTENDED and interphalangeal joints FLEXED, because the intrinsics are paralysed and the long extensors and flexors act unopposed • SENSORY: loss along the MEDIAL border of the forearm and hand, the C8 and T1 dermatomes • HORNER'S SYNDROME in about a third — ptosis, miosis, anhidrosis, enophthalmos — because the T1 root carries the preganglionic sympathetic fibres to the superior cervical ganglion. Its presence indicates a PREGANGLIONIC ROOT AVULSION and therefore a poor prognosis • Klumpke's is far rarer than Erb's • PROGNOSIS: neonatal Erb's palsy recovers spontaneously in 80 to 90 percent. Physiotherapy to prevent contracture, with exploration considered at three to six months if biceps function has not returned. Adult traction injuries do much worse; preganglionic avulsions need nerve transfers such as spinal accessory to suprascapular, or OBERLIN'S TRANSFER of ulnar nerve fascicles to the biceps branch of the musculocutaneous nerve
Identify the rotator cuff muscles and give their origin, insertion and nerve supply.Four muscles — SITS. Three insert on the greater tuberosity and one on the lesser. • SUPRASPINATUS — origin: the medial two-thirds of the SUPRASPINOUS FOSSA. Insertion: the SUPERIOR facet of the greater tuberosity. Nerve: SUPRASCAPULAR (C5, C6). Initiates the first 15 degrees of abduction • INFRASPINATUS — origin: the INFRASPINOUS FOSSA. Insertion: the MIDDLE facet of the greater tuberosity. Nerve: SUPRASCAPULAR (C5, C6). Lateral rotation • TERES MINOR — origin: the upper two-thirds of the LATERAL (axillary) border of the scapula. Insertion: the INFERIOR facet of the greater tuberosity. Nerve: AXILLARY (C5, C6) — the odd one out. Lateral rotation • SUBSCAPULARIS — origin: the SUBSCAPULAR FOSSA on the costal surface. Insertion: the LESSER TUBEROSITY. Nerve: UPPER and LOWER SUBSCAPULAR nerves (C5, C6, C7). Medial rotation. The only anterior one • THE SUPRASCAPULAR NERVE is worth knowing here: it arises from the UPPER TRUNK at Erb's point, passes through the suprascapular notch beneath the superior transverse scapular ligament — army goes UNDER the bridge, navy goes OVER, the artery passing above the ligament — then round the spinoglenoid notch to reach infraspinatus. It is injured in upper trunk lesions, and entrapped at either notch by a ganglion • FUNCTION as a group: they hold the humeral head centred in the shallow glenoid, giving deltoid the fulcrum it needs to abduct • HOW TO TEST ON THE MODEL: supraspinatus with Jobe's empty-can test, arm at 90 degrees abduction in 30 degrees of forward flexion, thumb down, resisted. Infraspinatus and teres minor with resisted EXTERNAL rotation at the side, and the external rotation lag sign. Subscapularis with GERBER'S LIFT-OFF test and the belly-press • Caution: TERES MAJOR is NOT part of the cuff — it is a medial rotator supplied by the LOWER SUBSCAPULAR nerve, inserting on the medial lip of the intertubercular groove
What is the origin and insertion of the deltoid muscle, and how would you test it on this patient?ORIGIN: a continuous line that exactly mirrors the insertion of trapezius — the anterior border and upper surface of the LATERAL THIRD OF THE CLAVICLE, the lateral border of the ACROMION, and the lower lip of the crest of the SPINE OF THE SCAPULA. INSERTION: the DELTOID TUBEROSITY on the middle of the lateral surface of the humeral shaft. • NERVE: the AXILLARY nerve (C5, C6), from the POSTERIOR CORD. It passes through the QUADRANGULAR SPACE with the posterior circumflex humeral artery, winds around the SURGICAL NECK of the humerus, and divides into an anterior branch to deltoid and a posterior branch to teres minor which continues as the upper lateral cutaneous nerve of the arm • ACTIONS by part: the ANTERIOR (clavicular) fibres flex and medially rotate; the MIDDLE (acromial) fibres, which are multipennate and the most powerful, abduct from about 15 to 90 degrees; the POSTERIOR (spinous) fibres extend and laterally rotate • HOW TO TEST IT ON THE PATIENT, in order • 1. INSPECT from in front and behind, comparing sides. Loss of the normal rounded contour, a squared-off shoulder with a prominent acromion, means deltoid wasting • 2. Ask them to ABDUCT the arm to 90 degrees. Push DOWN on the elbow while they resist, and PALPATE the muscle belly with your other hand to confirm it is contracting — this is what separates true deltoid function from trick movement using supraspinatus or trunk lean • 3. Test the three parts separately: resisted FLEXION for the anterior fibres, resisted ABDUCTION at 90 degrees for the middle, resisted EXTENSION for the posterior • 4. Test the AXILLARY NERVE SENSORY territory — light touch over the REGIMENTAL BADGE area on the lateral aspect of the upper arm, comparing both sides • 5. Document all of this BEFORE and AFTER any shoulder reduction • CLINICAL: the axillary nerve is injured in anterior shoulder dislocation, in surgical neck fractures of the humerus, and iatrogenically — never split deltoid more than 5 cm below the acromion, or you divide the nerve
What are the flexors of the elbow, and what is their nerve supply with root values?Three principal flexors, plus assistants, and the root value throughout is C5 and C6. • BRACHIALIS — the workhorse and the strongest. Origin: the lower half of the ANTERIOR SURFACE OF THE HUMERUS. Insertion: the CORONOID PROCESS and TUBEROSITY OF THE ULNA. Nerve: MUSCULOCUTANEOUS (C5, C6), with a small lateral part usually supplied by the RADIAL nerve (C7). That DUAL INNERVATION is worth saying — it is why some elbow flexion may survive an isolated musculocutaneous injury. Because it inserts on the ULNA, which does not rotate, its action is independent of forearm position • BICEPS BRACHII — Origin: LONG head from the SUPRAGLENOID TUBERCLE of the scapula, running through the joint and the intertubercular groove; SHORT head from the TIP OF THE CORACOID. Insertion: the RADIAL TUBEROSITY, plus the BICIPITAL APONEUROSIS (lacertus fibrosus) into the deep fascia of the forearm. Nerve: MUSCULOCUTANEOUS (C5, C6). It is both a flexor and the most powerful SUPINATOR, and flexes most efficiently with the forearm SUPINATED • BRACHIORADIALIS — Origin: the upper two-thirds of the LATERAL SUPRACONDYLAR RIDGE of the humerus. Insertion: the lateral aspect of the base of the RADIAL STYLOID. Nerve: RADIAL (C5, C6) — a flexor supplied by the nerve of the extensor compartment. Most efficient in MID-PRONATION • ASSISTANTS: pronator teres (median, C6, C7), extensor carpi radialis longus (radial, C6, C7), and the flexor-pronator mass from the medial epicondyle • REFLEX: the BICEPS JERK is C5 and C6; the SUPINATOR JERK is C6 • CLINICAL: rupture of the DISTAL BICEPS TENDON gives a Popeye deformity with a positive hook test, and — importantly — weakness of SUPINATION more than of flexion, because brachialis continues to flex. It needs early repair in an active patient. In a C5/C6 level tetraplegia, elbow flexion is preserved and forms the basis for functional tendon transfers
Name the nerves in the forearm.Three nerves cross the elbow into the forearm, and each has a deep, purely motor branch — name both levels. • MEDIAN NERVE (C6 to T1) — enters the cubital fossa MEDIAL to the brachial artery, passes BETWEEN THE TWO HEADS OF PRONATOR TERES, then runs between flexor digitorum superficialis and profundus to the wrist. It supplies ALL the flexors of the forearm EXCEPT flexor carpi ulnaris and the medial half of flexor digitorum profundus • Its branch the ANTERIOR INTEROSSEOUS NERVE is PURELY MOTOR, running on the interosseous membrane to supply flexor pollicis longus, the lateral half of flexor digitorum profundus and pronator quadratus. AIN palsy: cannot make an OK sign, with NO sensory loss • ULNAR NERVE (C8, T1) — enters behind the MEDIAL EPICONDYLE through the cubital tunnel, passes between the two heads of flexor carpi ulnaris, and descends on flexor digitorum profundus. In the forearm it supplies only FLEXOR CARPI ULNARIS and the MEDIAL HALF OF FLEXOR DIGITORUM PROFUNDUS. It gives the DORSAL CUTANEOUS branch about 5 cm above the wrist • RADIAL NERVE (C5 to T1) — enters anterior to the lateral epicondyle between brachialis and brachioradialis, and DIVIDES in front of the lateral epicondyle into • a SUPERFICIAL branch, purely SENSORY, running beneath brachioradialis and emerging to supply the dorsum of the radial hand • a DEEP branch, which pierces SUPINATOR at the ARCADE OF FROHSE to become the POSTERIOR INTEROSSEOUS NERVE, purely MOTOR, supplying all the extensors of the wrist and fingers. PIN palsy: finger drop with PRESERVED wrist extension, because extensor carpi radialis longus is supplied above the division, and NO sensory loss • THE CUTANEOUS NERVES of the forearm are a separate group and are frequently the real answer: the LATERAL cutaneous nerve of the forearm (the continuation of the MUSCULOCUTANEOUS nerve), the MEDIAL cutaneous nerve of the forearm (direct from the MEDIAL CORD, C8, T1), and the POSTERIOR cutaneous nerve of the forearm (from the RADIAL nerve) • If the examiner means the CUBITAL FOSSA specifically, its contents from LATERAL to MEDIAL are the radial nerve just outside the fossa, then the biceps Tendon, the brachial Artery and the Median nerve — TAN
Show me the biceps, triceps and supinator reflexes on this patient.Position the patient relaxed and seated with the arm supported, compare BOTH sides every time, and grade 0 to 4 — 0 absent, 1 present only with reinforcement, 2 normal, 3 brisk, 4 clonus. • BICEPS JERK — C5, C6, musculocutaneous nerve. Support the forearm semi-flexed and pronated across the patient's body. Place your THUMB firmly over the biceps tendon in the cubital fossa and strike YOUR OWN THUMB with the tendon hammer. Watch and feel for elbow flexion. Striking the tendon directly is uncomfortable and less reliable • SUPINATOR (brachioradialis) JERK — C6, radial nerve. Rest the forearm MID-PRONE across the patient's lap. Strike the distal radius about 5 cm proximal to the wrist, over the brachioradialis tendon. Watch for elbow flexion with a little supination. If instead you get FINGER FLEXION — the INVERTED SUPINATOR JERK — that indicates a cord lesion at C5/C6 with a reflex arc lost at that level and released below it • TRICEPS JERK — C7, with C8, radial nerve. Support the arm with the elbow flexed to 90 degrees across the body, or let the forearm hang over your own forearm. Strike the triceps tendon DIRECTLY, just proximal to the olecranon. Watch for elbow extension • IF A REFLEX SEEMS ABSENT, use REINFORCEMENT before you call it absent — JENDRASSIK'S MANOEUVRE: ask the patient to clench their teeth, or to interlock their fingers and pull hard, and strike again at the moment of pull • INTERPRETATION: a LOST reflex localises to its root value and indicates a lower motor neurone or root lesion. A BRISK reflex with an upgoing plantar indicates an upper motor neurone lesion above that level. In cervical myelopathy you classically find an ABSENT reflex at the level of the lesion with BRISK reflexes below it — that combination localises the cord level precisely
What is the sensory distribution of the ulnar, radial and median nerves in the forearm?This question has a trap in it, and the trap IS the answer. • The MEDIAN NERVE supplies NO SKIN in the forearm. Its most proximal cutaneous branch is the PALMAR CUTANEOUS branch, which arises about 5 cm above the wrist and supplies the thenar eminence and central palm — that is in the HAND, not the forearm • The ULNAR NERVE also supplies NO SKIN in the forearm. Its DORSAL CUTANEOUS branch arises about 5 cm above the wrist and supplies the dorsum of the medial hand • The RADIAL NERVE DOES supply forearm skin, through the POSTERIOR CUTANEOUS NERVE OF THE FOREARM, which arises in the spiral groove and runs down the middle of the back of the forearm. Its superficial branch supplies the dorsum of the hand, not the forearm • SO WHAT ACTUALLY SUPPLIES THE FOREARM SKIN? Three dedicated cutaneous nerves • LATERAL — the LATERAL CUTANEOUS NERVE OF THE FOREARM, the terminal sensory continuation of the MUSCULOCUTANEOUS nerve (C5, C6), emerging lateral to the biceps tendon at the elbow • MEDIAL — the MEDIAL CUTANEOUS NERVE OF THE FOREARM, a direct branch of the MEDIAL CORD (C8, T1) • POSTERIOR — the POSTERIOR CUTANEOUS NERVE OF THE FOREARM, from the RADIAL nerve • Say it plainly: in the forearm, the median and ulnar nerves have no cutaneous territory at all; the skin is supplied by the lateral, medial and posterior cutaneous nerves of the forearm • WHY IT MATTERS CLINICALLY: numbness in the FOREARM cannot be explained by carpal tunnel syndrome or by cubital tunnel syndrome. It points to a lesion at CORD level in the plexus, or to a cervical ROOT lesion. A patient with carpal tunnel symptoms who reports genuine forearm numbness has a second diagnosis • It also explains two surgical hazards: the LATERAL cutaneous nerve of the forearm is at risk in the anterior approach to the elbow and in distal biceps repair, and the MEDIAL cutaneous nerve of the forearm is at risk in cubital tunnel surgery and in basilic vein cannulation, where injury causes a painful neuroma
Demonstrate the action of brachioradialis on yourself, and describe its nerve supply.DEMONSTRATE: put your forearm in the MID-PRONE position — neutral, thumb pointing up — and flex the elbow against resistance. The easiest way at a station is to have the patient grip your hand as if to arm-wrestle, thumb up, and pull against you. Brachioradialis springs up as a prominent ridge forming the LATERAL BORDER OF THE CUBITAL FOSSA, running from the lateral supracondylar ridge to the radial styloid, and you can point to it on yourself or on the model • ACTION: it FLEXES THE ELBOW, and it is most efficient in MID-PRONATION. It also draws the forearm TOWARDS mid-prone from either extreme, so it acts as a weak pronator from full supination and a weak supinator from full pronation • It is the classic SHUNT MUSCLE: its line of pull is nearly parallel to the forearm, so most of its force compresses the joint surfaces together rather than producing rotation. That stabilises the elbow during rapid or heavily loaded flexion — which is why it is recruited most in fast movements and against resistance, and barely at all in slow unloaded flexion • ORIGIN: the upper two-thirds of the LATERAL SUPRACONDYLAR RIDGE of the humerus and the lateral intermuscular septum. INSERTION: the lateral side of the base of the RADIAL STYLOID PROCESS • NERVE SUPPLY: the RADIAL NERVE (C5, C6). The branch is given off in the ANTERIOR compartment, BEFORE the radial nerve divides into its superficial and deep branches • THAT IS THE POINT OF THE QUESTION: brachioradialis is a FLEXOR of the elbow supplied by the RADIAL nerve, the nerve of the extensor compartment. With extensor carpi radialis longus and supinator, it is one of the muscles supplied by the radial nerve proper around the elbow. Its reflex is the SUPINATOR JERK, C6 • CLINICAL LOCALISATION: because its branch leaves ABOVE the division, brachioradialis is PRESERVED in a posterior interosseous nerve palsy but LOST in a spiral groove lesion. Testing it is how you decide the level of a radial nerve injury • It is the key landmark for HENRY'S anterolateral approach to the radius, where the internervous plane lies between brachioradialis (radial) and flexor carpi radialis (median), and it is used as a tendon transfer to restore thumb flexion in tetraplegia
Name the tarsal bones and their articulations.SEVEN TARSAL BONES, in three groups • PROXIMAL (hindfoot) — TALUS and CALCANEUS • INTERMEDIATE — NAVICULAR • DISTAL — CUBOID and the THREE CUNEIFORMS (medial, intermediate, lateral) • A usable mnemonic: "Tall Californian Navy Cadets Marched In Line" — Talus, Calcaneus, Navicular, Cuboid, Medial, Intermediate, Lateral cuneiform • ARTICULATIONS — TALUS: above with the tibia and fibula (ankle / talocrural), below with the calcaneus (subtalar), in front with the navicular (talonavicular). It is the only tarsal bone with NO MUSCLE ATTACHED to it • CALCANEUS: above with the talus (three facets — posterior, middle on the sustentaculum tali, anterior), in front with the cuboid (calcaneocuboid) • NAVICULAR: behind with the head of the talus, in front with all three cuneiforms, and sometimes laterally with the cuboid • CUBOID: behind with the calcaneus, in front with the 4th and 5th metatarsals, medially with the lateral cuneiform and sometimes the navicular • CUNEIFORMS: medial → 1st metatarsal, intermediate → 2nd, lateral → 3rd • TWO NAMED COMPOSITE LINES the examiner may push you to: the MIDTARSAL (transverse tarsal, CHOPART'S) joint = talonavicular + calcaneocuboid, and the TARSOMETATARSAL (LISFRANC) line • Note the 2nd metatarsal is recessed between the medial and lateral cuneiforms — the keystone of the Lisfranc joint, which is why a Lisfranc injury is so easily missed.
Name the arches of the foot and the components of each.THREE ARCHES — two longitudinal, one transverse • MEDIAL LONGITUDINAL ARCH — the higher, more mobile, more resilient arch. BONES: calcaneus, talus, navicular, the three cuneiforms and the medial three metatarsals. KEYSTONE: the head of the talus. SUPPORT: the SPRING (plantar calcaneonavicular) LIGAMENT is the critical one — it slings the head of the talus between the sustentaculum tali and the navicular; also the deltoid ligament, plantar aponeurosis, and dynamically TIBIALIS POSTERIOR (the main dynamic support), tibialis anterior, flexor hallucis longus, flexor digitorum longus and abductor hallucis • LATERAL LONGITUDINAL ARCH — flatter, in contact with the ground, built for weight transmission. BONES: calcaneus, cuboid and the lateral two metatarsals. SUPPORT: long plantar and short plantar (plantar calcaneocuboid) ligaments, plantar aponeurosis, peroneus longus and brevis, abductor digiti minimi • TRANSVERSE ARCH — across the foot at the bases of the metatarsals, the cuboid and the cuneiforms. It is a HALF arch: complete only when the two feet are placed together. SUPPORT: PERONEUS LONGUS above all — its tendon crosses the sole obliquely and acts as a tie-beam — plus tibialis posterior, the transverse head of adductor hallucis and the deep transverse metatarsal ligaments • CLINICALLY: tibialis posterior tendon dysfunction is the commonest cause of acquired adult flatfoot — the medial arch collapses, the heel goes into valgus and you see the "too many toes" sign from behind.
What are the structures passing under the extensor retinaculum?SIX structures, and the examiner wants them in ORDER FROM MEDIAL TO LATERAL • 1. TIBIALIS ANTERIOR tendon • 2. EXTENSOR HALLUCIS LONGUS tendon • 3. ANTERIOR TIBIAL ARTERY with its venae comitantes — which becomes the DORSALIS PEDIS as it crosses the ankle • 4. DEEP PERONEAL (FIBULAR) NERVE • 5. EXTENSOR DIGITORUM LONGUS tendon • 6. PERONEUS TERTIUS • The neurovascular bundle sits BETWEEN extensor hallucis longus and extensor digitorum longus — that is the single fact worth memorising, because it tells you where to feel the pulse and what is at risk • THE RETINACULUM ITSELF: the SUPERIOR extensor retinaculum is a simple transverse band between tibia and fibula above the malleoli. The INFERIOR extensor retinaculum is Y-SHAPED — its stem attached laterally to the calcaneus, dividing into upper and lower bands medially • FUNCTION: it prevents BOWSTRINGING of the long extensor tendons during dorsiflexion • Each tendon has its own synovial sheath beneath it.
Which are the structures behind the medial malleolus? Show them on the prosection.These lie in the TARSAL TUNNEL, deep to the FLEXOR RETINACULUM, which runs from the medial malleolus to the medial process of the calcaneal tuberosity • FROM FRONT TO BACK: TIBIALIS POSTERIOR tendon • FLEXOR DIGITORUM LONGUS tendon • POSTERIOR TIBIAL ARTERY with its venae comitantes • TIBIAL NERVE • FLEXOR HALLUCIS LONGUS tendon • MNEMONIC: "TOM, DICK and a Very Nervous Harry" — Tibialis posterior, flexor Digitorum longus, posterior tibial Artery, Vein, tibial Nerve, flexor Hallucis longus • ON THE PROSECTION: put your finger on the medial malleolus, then sweep BACKWARDS and DOWNWARDS in a curve towards the heel — that curve is the retinaculum, and the structures cross under it in that order • THE PULSE: the posterior tibial pulse is felt midway between the medial malleolus and the heel — remember it is DEEP to the retinaculum, so press firmly • CLINICALLY: TARSAL TUNNEL SYNDROME — compression of the tibial nerve here gives burning pain and paraesthesia in the SOLE (not the dorsum), worse on standing, with a positive Tinel's behind the medial malleolus • Note flexor hallucis longus is the most posterior and passes in a groove UNDER THE SUSTENTACULUM TALI.
Which artery is affected when there is an injury to the extensor retinaculum?The DORSALIS PEDIS ARTERY — the direct continuation of the ANTERIOR TIBIAL ARTERY, which takes that name as it crosses the ankle joint at the level of the inferior extensor retinaculum • WHY IT IS AT RISK: it passes DIRECTLY BENEATH the inferior extensor retinaculum, lying on the capsule of the ankle joint and then on the talus, navicular and intermediate cuneiform, sandwiched BETWEEN the tendons of EXTENSOR HALLUCIS LONGUS medially and EXTENSOR DIGITORUM LONGUS laterally, with the DEEP PERONEAL NERVE alongside it • It is superficial, tethered, and has bone immediately beneath it — so a laceration across the front of the ankle, or a crush that tears the retinaculum, takes the artery and usually the deep peroneal nerve with it • CONSEQUENCE: loss of the dorsalis pedis pulse; the foot usually survives on the posterior tibial and peroneal supply through the plantar arch, but check capillary refill and the plantar circulation before you accept that • A DEEP PERONEAL NERVE injury alongside it gives loss of sensation in the FIRST WEB SPACE and weak toe extension • Worth saying out loud: in about 2–3% of people the dorsalis pedis is congenitally absent or tiny, replaced by the perforating branch of the peroneal artery — so an absent pulse is not automatically pathological.
Identify the structure marked on this lateral X-ray of the foot.The SUSTENTACULUM TALI — the shelf of bone projecting MEDIALLY from the anterosuperior part of the calcaneus • WHAT IT DOES: it carries the MIDDLE FACET of the calcaneus and literally supports the neck and body of the TALUS — "sustentaculum tali" means the support of the talus • ITS RELATIONS, which is what the examiner is really after: ABOVE — the middle talocalcaneal facet. BELOW — a groove for the tendon of FLEXOR HALLUCIS LONGUS. MEDIALLY — the tibiocalcaneal part of the DELTOID LIGAMENT attaches to its upper medial edge. ANTERIORLY — the SPRING (plantar calcaneonavicular) LIGAMENT runs from its front edge to the navicular • SURFACE LANDMARK: palpable about 2 cm BELOW the tip of the medial malleolus • CLINICALLY: in an intra-articular CALCANEAL FRACTURE the sustentacular fragment is the CONSTANT FRAGMENT — it stays attached to the talus through the strong interosseous talocalcaneal ligament and the deltoid, so it does not move and is used as the reference point for reduction and for screw fixation • Also look for BOHLER'S ANGLE on this lateral film (normal 20–40°); flattening indicates a depressed calcaneal fracture.
Identify the following on the prosection: the deltoid ligament, the calcaneofibular ligament and the posterior talofibular ligament.MEDIAL SIDE — the DELTOID (medial collateral) LIGAMENT: a strong triangular fan from the MEDIAL MALLEOLUS spreading down to the talus, calcaneus and navicular. Two layers, FOUR PARTS • SUPERFICIAL: tibionavicular, tibiocalcaneal (to the sustentaculum tali) and posterior tibiotalar • DEEP: anterior tibiotalar — the strongest part, and the one that carries the deltoid arterial branches to the talar body • LATERAL SIDE — three separate bands, NOT a fan • ANTERIOR TALOFIBULAR (ATFL): from the front of the lateral malleolus forwards to the neck of the talus. The WEAKEST, and the FIRST to tear in an inversion injury • CALCANEOFIBULAR (CFL): from the tip of the lateral malleolus downwards and backwards to the lateral surface of the calcaneus. It is the only one of the three that crosses BOTH the ankle and the subtalar joint, and it lies deep to the peroneal tendons • POSTERIOR TALOFIBULAR (PTFL): from the malleolar fossa backwards and medially to the posterior tubercle of the talus. The STRONGEST, and torn only in a frank dislocation • SEQUENCE OF INJURY: ATFL, then CFL, then PTFL — so an isolated PTFL tear does not exist in practice • TESTS: ANTERIOR DRAW tests the ATFL; TALAR TILT tests the CFL.
Which are the components of the ankle joint?The TALOCRURAL joint — a MORTISE AND TENON • THE MORTISE (the socket) is made of THREE parts: the inferior articular surface of the TIBIA (the plafond), the MEDIAL MALLEOLUS of the tibia, and the LATERAL MALLEOLUS of the FIBULA • THE TENON is the TROCHLEA (body) of the TALUS, which is gripped between the two malleoli • The lateral malleolus descends about 1 cm LOWER and more POSTERIORLY than the medial — which is why the talus tilts more readily into inversion than eversion • HELD BY • the INFERIOR TIBIOFIBULAR SYNDESMOSIS (anterior and posterior tibiofibular ligaments, the interosseous ligament continuous with the interosseous membrane, and the inferior transverse ligament) — this is what keeps the mortise the right WIDTH • the DELTOID ligament medially • the LATERAL COLLATERAL COMPLEX — ATFL, CFL and PTFL • A thin, lax capsule in front and behind to permit the hinge • CLINICALLY: the ankle is a RING — medial malleolus + deltoid, lateral malleolus + lateral ligaments, and the syndesmosis. A ring cannot break in only one place and stay stable: if you see one clear injury on the X-ray, look hard for the second. That is the whole logic of the Weber and Lauge-Hansen classifications.
What is the type of the ankle joint and what movements occur there?TYPE: a SYNOVIAL HINGE (ginglymus) joint — UNIAXIAL • The axis runs transversely, roughly through the tips of the two malleoli, and is slightly oblique — running downwards and laterally — so pure plantarflexion is accompanied by a little adduction and supination • MOVEMENTS: DORSIFLEXION about 20–30° and PLANTARFLEXION about 40–50°. That is ALL • The single commonest error is to claim inversion and eversion happen at the ankle. They DO NOT — those are SUBTALAR and MIDTARSAL movements. If you are asked to test the ankle, move the foot up and down only • DORSIFLEXORS: tibialis anterior (chiefly), extensor hallucis longus, extensor digitorum longus, peroneus tertius — all DEEP PERONEAL NERVE • PLANTARFLEXORS: gastrocnemius and soleus (chiefly), with plantaris, tibialis posterior, flexor hallucis longus, flexor digitorum longus and, weakly, the peronei — mostly TIBIAL NERVE • The plantarflexors are far more powerful: they lift the whole body weight onto the toes, which is why single heel raise is the test of Achilles and tibialis posterior function.
What muscles insert at the medial cuneiform?THREE • TIBIALIS ANTERIOR — into the MEDIAL and INFERIOR surface of the medial cuneiform AND the base of the 1st metatarsal. Deep peroneal nerve. Dorsiflexes and inverts • PERONEUS LONGUS — into the LATERAL side of the medial cuneiform AND the base of the 1st metatarsal, reaching them by crossing the SOLE obliquely from the lateral side. Superficial peroneal nerve. Everts and plantarflexes • TIBIALIS POSTERIOR — sends slips to the medial cuneiform, though its principal insertion is the TUBEROSITY OF THE NAVICULAR, with further slips to the other cuneiforms, the cuboid, the sustentaculum tali and the bases of the 2nd–4th metatarsals. Tibial nerve • THE POINT THE EXAMINER IS DRIVING AT: tibialis anterior and peroneus longus insert on the SAME two bones from OPPOSITE sides, forming a STIRRUP or SLING beneath the foot • They are antagonists in the coronal plane — tibialis anterior inverts, peroneus longus everts — but they act TOGETHER as the chief dynamic support of the TRANSVERSE ARCH, and together they balance the foot on the ground during stance.
In which movement is the ankle joint more stable, and why?In DORSIFLEXION • THE REASON is the shape of the TROCHLEA OF THE TALUS: it is WEDGE-SHAPED, WIDER IN FRONT than behind — by about 5 mm • ON DORSIFLEXION the wider ANTERIOR part of the trochlea is drawn up into the mortise. It wedges the two malleoli apart, the lateral malleolus rotates and moves laterally, and the syndesmosis is put under tension. The joint surfaces are maximally congruent and all the ligaments are taut — this is the CLOSE-PACKED position, and the ankle is at its most stable • ON PLANTARFLEXION the NARROWER POSTERIOR part sits in the mortise, so there is slack between the talus and the malleoli. The ligaments are relaxed and a small degree of side-to-side rock and rotation becomes possible — the LOOSE-PACKED position • CLINICAL CONSEQUENCES, which is what makes this worth knowing • Inversion injuries happen in PLANTARFLEXION — coming down off a kerb or a stair, landing from a jump. That is when the ATFL tears • The ATFL is also the ligament that is taut in plantarflexion, which is why the anterior draw test is performed with the ankle slightly plantarflexed • Ankles should be immobilised in a plaster in DORSIFLEXION (the plantigrade position) — an ankle held plantarflexed stiffens into equinus and is very hard to recover.
Which are the components of the subtalar joint, and what movement occurs there?STRICTLY, the SUBTALAR (posterior talocalcaneal) joint is between the CONCAVE POSTERIOR FACET on the underside of the BODY OF THE TALUS and the CONVEX POSTERIOR FACET on the upper surface of the CALCANEUS. It has its own capsule and its own synovial cavity. Type: SYNOVIAL PLANE (gliding) joint • CLINICALLY, and in most exam answers, the SUBTALAR COMPLEX also includes the TALOCALCANEONAVICULAR joint in front — the head of the talus in a socket formed by the navicular, the anterior and middle facets of the calcaneus and the SPRING LIGAMENT. That part is a SYNOVIAL BALL-AND-SOCKET joint • The two are separated by the SINUS TARSI and CANALIS TARSI, which contain the strong INTEROSSEOUS TALOCALCANEAL (CERVICAL) LIGAMENT — the principal stabiliser • Also the medial, lateral and posterior talocalcaneal ligaments, and the calcaneofibular ligament crossing it laterally • MOVEMENT: INVERSION and EVERSION — the calcaneus and the rest of the foot rotating BENEATH a talus that is locked in the ankle mortise • The axis is OBLIQUE — running upwards, forwards and medially — so the movement is TRIPLANAR: inversion = supination + adduction + plantarflexion; eversion = pronation + abduction + dorsiflexion • Range roughly 20° inversion, 10° eversion — inversion is always the greater • This is the joint that lets you walk on uneven ground.
Which are the components of the midtarsal joint?The MIDTARSAL — also called the TRANSVERSE TARSAL or CHOPART'S — joint is a COMPOUND joint made of TWO SEPARATE joints that happen to lie in the same S-shaped line across the foot • 1. The TALONAVICULAR joint — the head of the talus with the navicular. It is part of the larger TALOCALCANEONAVICULAR joint, so it shares that synovial cavity. BALL-AND-SOCKET type • 2. The CALCANEOCUBOID joint — the anterior surface of the calcaneus with the cuboid. It has its OWN separate capsule and cavity. SADDLE type • They are NOT one cavity, and saying so is a common slip • LIGAMENTS: the BIFURCATE LIGAMENT is the key — a Y from the front of the calcaneus dividing into a CALCANEONAVICULAR part and a CALCANEOCUBOID part, and it is the ligament that holds the line together. Also the dorsal talonavicular, the long plantar and the short plantar (plantar calcaneocuboid) ligaments, and the spring ligament beneath the talar head • FUNCTION: it ADDS to the inversion and eversion of the subtalar joint, and it locks and unlocks the foot — supination makes the two axes diverge and the foot becomes a RIGID LEVER for push-off; pronation makes them parallel and the foot becomes a FLEXIBLE shock absorber at heel strike • CLINICALLY: CHOPART'S is a classical amputation level, and the bifurcate ligament avulses a fleck off the anterior process of the calcaneus in an inversion injury.
What are the complications of a fracture of the neck of the talus?AVASCULAR NECROSIS of the BODY of the talus is the one to say first — the blood supply runs RETROGRADE, from distal to proximal, so a fracture across the neck cuts the body off from its supply • HAWKINS CLASSIFICATION and the AVN risk that goes with it • TYPE I — undisplaced neck fracture: AVN roughly 0–15% • TYPE II — displaced, with subtalar subluxation or dislocation: 20–50% • TYPE III — displaced, with the body dislocated from BOTH the subtalar and the ankle joint: 80–100% • TYPE IV — as III plus talonavicular dislocation: approaching 100% • THE HAWKINS SIGN: a thin SUBCHONDRAL LUCENT LINE in the talar dome on an AP film at 6–8 weeks. Its PRESENCE indicates revascularisation and is a GOOD sign; its ABSENCE suggests AVN • OTHER COMPLICATIONS • POST-TRAUMATIC OSTEOARTHRITIS of the subtalar and ankle joints — actually the commonest long-term problem, more frequent than AVN • MALUNION, typically in VARUS, giving a foot that walks on its lateral border • NON-UNION • SKIN NECROSIS and OPEN INJURY — a displaced body tents the skin medially and this is a surgical emergency • COMPARTMENT SYNDROME OF THE FOOT • INFECTION in open injuries • Because it is a high-energy injury, look for an associated calcaneal fracture and a lumbar spine fracture.
What is the blood supply to the talus?The talus is a difficult bone: about 60% of its surface is ARTICULAR CARTILAGE, and NO MUSCLE OR TENDON is attached to it. So vessels can only enter through the small non-articular areas of the NECK, the medial body and the posterior process — and much of the flow to the body is RETROGRADE • THREE SOURCE ARTERIES, all branches of the popliteal • 1. POSTERIOR TIBIAL ARTERY — gives the ARTERY OF THE TARSAL CANAL, which runs in the canalis tarsi and is the DOMINANT supply to the BODY of the talus. The posterior tibial also gives DELTOID BRANCHES that run in the deltoid ligament to the MEDIAL BODY — these are often the only supply that survives a displaced neck fracture, which is why the deltoid must not be stripped at operation • 2. ANTERIOR TIBIAL / DORSALIS PEDIS — branches to the superior surface of the NECK and the HEAD • 3. PERONEAL ARTERY — its perforating branch contributes to the ARTERY OF THE SINUS TARSI, which anastomoses with a branch of the lateral tarsal artery from the dorsalis pedis to form an ARTERIAL SLING beneath the talar neck, supplying the lateral half of the head and neck • PUT IT TOGETHER: head and neck are supplied ANTEGRADE and heal well; the BODY depends on vessels running BACKWARDS through the neck, so a displaced talar neck fracture strips them and the body dies • The same retrograde principle applies to the scaphoid and the femoral head — worth saying, examiners like the parallel.
Identify the following on the prosection: the 5th metatarsal, the base of the 5th metatarsal and the tuberosity of the 5th metatarsal.Work from proximal to distal and name what you touch • THE 5TH METATARSAL is the most LATERAL of the five, on the outer border of the foot. It has a BASE proximally, a SHAFT, a NECK and a HEAD distally • THE BASE is the expanded proximal end. It articulates PROXIMALLY with the CUBOID and MEDIALLY with the base of the 4th metatarsal • THE TUBEROSITY (also called the STYLOID PROCESS) is the blunt projection that sticks out LATERALLY and slightly BACKWARDS from the base. It is the prominence you can feel through the skin halfway along the lateral border of the foot • FINDING IT ON A LIVE FOOT: run your finger backwards along the outer border from the little toe and you will meet a distinct bump about halfway — that is the tuberosity, and it is one of the palpation points in the OTTAWA ANKLE RULES • WHY THE DISTINCTION MATTERS: the TUBEROSITY, the METAPHYSEAL-DIAPHYSEAL JUNCTION and the PROXIMAL SHAFT are three different fracture zones with three different prognoses, and calling all of them a "Jones fracture" is the classic error.
What is inserted into the tuberosity of the 5th metatarsal?PERONEUS (FIBULARIS) BREVIS — this is the answer the examiner wants. Its tendon runs behind the lateral malleolus, beneath the peroneal retinacula, forwards over the lateral side of the calcaneus and inserts into the tuberosity • ALSO ATTACHED THERE • the LATERAL CORD (lateral band) of the PLANTAR APONEUROSIS • part of the origin of ABDUCTOR DIGITI MINIMI, from the lateral part of the base • THE TRAP: PERONEUS TERTIUS does NOT insert into the tuberosity. It inserts into the DORSAL SURFACE of the BASE and SHAFT of the 5th metatarsal, and it belongs to the ANTERIOR compartment with the DEEP PERONEAL nerve — not the lateral compartment. Confusing the two is the commonest mistake on this question • Nor does PERONEUS LONGUS attach here — it passes the tuberosity, turns into the sole under the cuboid, and travels right across to the MEDIAL side of the foot to reach the base of the 1st metatarsal and the medial cuneiform • So: brevis stops SHORT and laterally; longus goes ALL THE WAY ACROSS.
What type of injury and what fracture can happen at the tuberosity of the 5th metatarsal?MECHANISM: forced INVERSION with the foot PLANTARFLEXED — going over on the ankle. Exactly the same mechanism as a lateral ligament sprain, which is why the two are confused and why the OTTAWA ANKLE RULES make you palpate the base of the 5th metatarsal in every "sprained ankle" • THE FRACTURE is an AVULSION FRACTURE of the tuberosity — sometimes called a PSEUDO-JONES or dancer's fracture — pulled off by PERONEUS BREVIS and/or the lateral cord of the plantar aponeurosis • KNOW THE THREE ZONES (Lawrence and Botte) because the treatment differs completely • ZONE 1 — the TUBEROSITY avulsion. Good blood supply, unites reliably. Treated symptomatically in a walking boot or stiff-soled shoe, weight-bearing as tolerated • ZONE 2 — the JONES FRACTURE, at the metaphyseal-diaphyseal junction, extending into the 4th–5th intermetatarsal articulation. This sits in a vascular WATERSHED, so delayed union and non-union are common. Non-weight-bearing cast, or intramedullary screw fixation in athletes and the high-demand patient • ZONE 3 — the proximal DIAPHYSEAL STRESS fracture, typically in a runner or dancer, with a history of prodromal pain • IN A CHILD, do not mistake the normal APOPHYSIS for a fracture: the apophysis lies PARALLEL or oblique to the shaft, whereas an avulsion fracture line runs TRANSVERSE to it. An OS VESALIANUM is a further accessory ossicle that catches people out.
Where do you feel the dorsalis pedis pulse?On the DORSUM OF THE FOOT, just LATERAL to the tendon of EXTENSOR HALLUCIS LONGUS, in the interval between the 1st and 2nd metatarsal bases • HOW TO FIND IT ON THE ACTOR, said out loud: ask them to extend the great toe so the EHL tendon stands out; place two fingers immediately LATERAL to that tendon; press gently against the underlying tarsal bones — the navicular and the intermediate cuneiform • ANOTHER WAY TO DESCRIBE IT: midway between the two malleoli, then follow the line distally towards the first web space • THE COURSE: the anterior tibial artery becomes the dorsalis pedis at the level of the ankle joint under the inferior extensor retinaculum, runs distally with the DEEP PERONEAL NERVE, and at the proximal end of the first intermetatarsal space divides into the FIRST DORSAL METATARSAL artery and the DEEP PLANTAR artery, which dives between the two heads of the first dorsal interosseous to complete the PLANTAR ARCH • IMPORTANT CAVEAT: the dorsalis pedis is congenitally ABSENT or hypoplastic in about 2–3% of people, replaced by the perforating branch of the peroneal artery — so an impalpable pulse in isolation is not proof of disease. Always check the POSTERIOR TIBIAL as well, midway between the medial malleolus and the heel.
Which tendons and muscles are attached to the calcaneus?Take the bone surface by surface • POSTERIOR SURFACE — the TENDOCALCANEUS (ACHILLES TENDON), the conjoint tendon of GASTROCNEMIUS and SOLEUS, into the MIDDLE third of the posterior surface. The upper third is separated from it by the retrocalcaneal bursa and the lower third by subcutaneous tissue. PLANTARIS inserts just MEDIAL to the Achilles • PLANTAR (INFERIOR) SURFACE, from the calcaneal tuberosity — the MEDIAL PROCESS gives origin to ABDUCTOR HALLUCIS, FLEXOR DIGITORUM BREVIS and the PLANTAR APONEUROSIS; the LATERAL PROCESS gives origin to ABDUCTOR DIGITI MINIMI • QUADRATUS PLANTAE (flexor accessorius) arises by two heads from the medial and lateral surfaces of the calcaneus • DORSAL / ANTEROLATERAL SURFACE — EXTENSOR DIGITORUM BREVIS arises from the upper lateral surface in front of the sinus tarsi • TENDONS THAT GROOVE THE BONE BUT DO NOT INSERT ON IT — a favourite distinction: FLEXOR HALLUCIS LONGUS in the groove UNDER the sustentaculum tali, and PERONEUS LONGUS and BREVIS in grooves on the LATERAL surface, separated by the peroneal tubercle • LIGAMENTS for completeness: the long and short plantar ligaments, the spring ligament from the sustentaculum tali, the bifurcate ligament, the calcaneofibular ligament and the interosseous talocalcaneal ligament • CLINICALLY: insertional Achilles tendinopathy and Haglund's deformity posteriorly; plantar fasciitis at the medial process.
You are shown the actual bone in oblique, AP and lateral views: is this a right or a left FIBULA?Do not guess. Say the steps out loud and let the bone answer • STEP 1 — FIND THE DISTAL END. It is the expanded, FLATTENED, blade-like end: the LATERAL MALLEOLUS. The proximal end is a rounded HEAD with a blunt apex or styloid process pointing upwards and backwards • STEP 2 — ORIENT THE MALLEOLUS DOWNWARDS • STEP 3 — FIND THE MALLEOLAR FOSSA. On the MEDIAL surface of the lateral malleolus there is a smooth TRIANGULAR FACET for the talus, and immediately BEHIND it a deep pit — the MALLEOLAR FOSSA, for the posterior talofibular ligament. TURN THE FOSSA SO IT FACES BACKWARDS AND MEDIALLY • STEP 4 — READ OFF THE SIDE. With the malleolus pointing down and the fossa facing posteromedially, THE SIDE THE BONE NOW LIES ON IS THE SIDE OF THE BODY IT CAME FROM • CROSS-CHECKS you can offer • the articular facet for the talus faces MEDIALLY • the tip of the lateral malleolus lies about 1 cm LOWER and more POSTERIOR than the medial malleolus • the sharp INTEROSSEOUS BORDER of the shaft faces MEDIALLY, towards the tibia • at the proximal end the FACET ON THE HEAD for the tibia faces upwards, forwards and MEDIALLY • A useful clinical aside: the fibula carries almost no body weight — perhaps a sixth — which is why long segments of it can be harvested as a vascularised bone graft.
Now the same for the tibia: is this a right or a left tibia?Same discipline — three landmarks, then read the side off the bone • STEP 1 — WHICH END IS WHICH. The PROXIMAL end is much larger, with the MEDIAL and LATERAL CONDYLES and the flat tibial plateau bearing the intercondylar eminence. The DISTAL end is smaller and carries the MEDIAL MALLEOLUS • STEP 2 — PUT THE TUBEROSITY IN FRONT. The TIBIAL TUBEROSITY is the obvious roughened prominence below the plateau — it is ANTERIOR. The sharp ANTERIOR BORDER (the shin) runs down from it • STEP 3 — LET THE MEDIAL MALLEOLUS TELL YOU THE SIDE. Hold the bone upright, tuberosity facing forwards, malleolus pointing DOWN — the MEDIAL MALLEOLUS projects to the MEDIAL side, so whichever side it points to is the side of the body • CROSS-CHECKS • the FIBULAR NOTCH on the distal end is LATERAL, a rough triangular hollow for the syndesmosis • the FIBULAR FACET on the underside of the LATERAL condyle faces downwards, backwards and laterally • the groove on the back of the medial malleolus (for tibialis posterior and flexor digitorum longus) is POSTERIOR • the medial surface of the shaft is smooth and SUBCUTANEOUS the whole way down — that is why tibial fractures are so often open, and why the tibia is the site for intraosseous access, 2 cm below and medial to the tuberosity • Note also the SOLEAL LINE running obliquely downwards and medially on the posterior surface — another posterior marker.
Which muscles are responsible for the movements of the ankle joint?Answer by MOVEMENT, and give the nerve with each group — that is what earns the marks • DORSIFLEXION — the ANTERIOR COMPARTMENT, all supplied by the DEEP PERONEAL (FIBULAR) NERVE (L4, L5) • TIBIALIS ANTERIOR (the principal dorsiflexor) • EXTENSOR HALLUCIS LONGUS • EXTENSOR DIGITORUM LONGUS • PERONEUS TERTIUS • PLANTARFLEXION — the POSTERIOR COMPARTMENT, TIBIAL NERVE (S1, S2) • GASTROCNEMIUS and SOLEUS, together the TRICEPS SURAE, doing the great majority of the work • assisted by PLANTARIS, TIBIALIS POSTERIOR, FLEXOR HALLUCIS LONGUS, FLEXOR DIGITORUM LONGUS and, weakly, PERONEUS LONGUS and BREVIS • The plantarflexors are far the stronger group — they raise the entire body weight onto the toes, which the dorsiflexors could never do • INVERSION — TIBIALIS ANTERIOR (deep peroneal) and TIBIALIS POSTERIOR (tibial). Both begin with "tibialis", which is the easy way to remember it • EVERSION — PERONEUS LONGUS and PERONEUS BREVIS (SUPERFICIAL PERONEAL nerve, L5–S1), assisted by peroneus tertius (deep peroneal) • BUT SAY THIS CLEARLY: inversion and eversion do NOT occur at the ankle joint. They occur at the SUBTALAR and MIDTARSAL joints. The ankle only dorsiflexes and plantarflexes • QUICK CLINICAL TEST OF EACH NERVE: dorsiflex the ankle = deep peroneal; evert the foot = superficial peroneal; plantarflex = tibial.
Demonstrate inversion and eversion of the ankle on yourself. At which joint do these movements happen, and what type of joint is it?DEMONSTRATE IT PROPERLY — the examiner is watching your technique, not your flexibility • Sit with the KNEE FLEXED and hold the ankle in NEUTRAL or slight plantarflexion — this relaxes the ankle joint and isolates the movement below it • INVERSION: turn the SOLE to face MEDIALLY, towards the other foot. Roughly 20° • EVERSION: turn the SOLE to face LATERALLY, away from the midline. Roughly 10°, always the smaller of the two • Say aloud why: the lateral malleolus descends LOWER than the medial and buttresses the talus, so the foot inverts more readily than it everts — and that is also why inversion injuries are so much commoner • THE JOINT: NOT the ankle. These occur at the SUBTALAR (TALOCALCANEAL) joint, assisted by the MIDTARSAL joint — the talonavicular and calcaneocuboid joints • THE TYPE • the posterior talocalcaneal (subtalar proper) joint is a SYNOVIAL PLANE (gliding) joint • the talocalcaneonavicular part in front is a SYNOVIAL BALL-AND-SOCKET joint — the head of the talus in a socket of navicular, spring ligament and the anterior and middle calcaneal facets • the calcaneocuboid joint is a SYNOVIAL SADDLE joint • The AXIS is OBLIQUE, so all of these are TRIPLANAR: full inversion is really SUPINATION with adduction and plantarflexion; full eversion is PRONATION with abduction and dorsiflexion • FIXING THE ANKLE: if you dorsiflex the ankle fully first, the wide part of the talus locks in the mortise and any residual movement you produce MUST be subtalar — that is how you examine the subtalar joint in isolation.
Identify these structures on the prosection and say where they insert (peroneus longus and peroneus brevis).Both are the LATERAL COMPARTMENT of the leg, and both are supplied by the SUPERFICIAL PERONEAL (FIBULAR) NERVE (L5, S1, S2) • HOW TO TELL THEM APART ON THE SPECIMEN: at the level of the lateral malleolus, PERONEUS BREVIS lies ANTERIOR and DEEPER, in direct contact with the bone; PERONEUS LONGUS lies POSTERIOR and SUPERFICIAL to it. Both run in a common synovial sheath behind the malleolus, held by the SUPERIOR PERONEAL RETINACULUM, then separate below the PERONEAL TUBERCLE of the calcaneus under the INFERIOR PERONEAL RETINACULUM • PERONEUS BREVIS — ORIGIN: lower two-thirds of the LATERAL surface of the fibula. INSERTION: the TUBEROSITY OF THE BASE OF THE 5TH METATARSAL. It is the SHORT one and it stops SHORT, on the lateral side • PERONEUS LONGUS — ORIGIN: head and upper two-thirds of the lateral surface of the fibula. Its tendon passes behind the lateral malleolus, then turns beneath the CUBOID in the peroneal groove — held down by the LONG PLANTAR LIGAMENT — and crosses the SOLE OBLIQUELY to insert into the BASE OF THE 1ST METATARSAL and the LATERAL SIDE OF THE MEDIAL CUNEIFORM. It is the LONG one and it goes ALL THE WAY ACROSS • ACTIONS: both EVERT the foot and assist plantarflexion. Peroneus longus is the chief dynamic support of the TRANSVERSE ARCH and, with tibialis anterior, forms the STIRRUP under the foot • CLINICALLY: peroneal tendon subluxation when the superior retinaculum is torn — the tendons snap forwards over the malleolus; and avulsion of the 5th metatarsal base by peroneus brevis in an inversion injury.
What are the compartments of the leg, the muscles in each, and the nerve supply of each?FOUR compartments, bounded by the tibia, fibula, interosseous membrane and the deep fascia with its anterior and posterior intermuscular septa • 1. ANTERIOR — MUSCLES: tibialis anterior, extensor hallucis longus, extensor digitorum longus, peroneus tertius. NERVE: DEEP PERONEAL. ARTERY: anterior tibial. ACTION: dorsiflexion and toe extension. This is the compartment most often affected by compartment syndrome, and the one to check first • 2. LATERAL — MUSCLES: peroneus longus and peroneus brevis. NERVE: SUPERFICIAL PERONEAL. ARTERY: no artery of its own; supplied by branches of the peroneal artery. ACTION: eversion • 3. SUPERFICIAL POSTERIOR — MUSCLES: gastrocnemius, soleus, plantaris. NERVE: TIBIAL. ARTERY: sural branches. ACTION: plantarflexion • 4. DEEP POSTERIOR — MUSCLES: tibialis posterior, flexor digitorum longus, flexor hallucis longus, and popliteus at the top. NERVE: TIBIAL. ARTERIES: posterior tibial and peroneal. ACTION: plantarflexion, inversion and toe flexion • (Some texts add a fifth, a separate peroneal artery compartment) • EXAM-READY MAPPING OF NERVE TO ACTION: deep peroneal = dorsiflexion; superficial peroneal = eversion; tibial = plantarflexion and inversion • COMPARTMENT SYNDROME: pain out of proportion, pain on PASSIVE STRETCH of the muscles in that compartment (the earliest reliable sign), tense swelling, paraesthesia. Pulses and capillary refill are preserved until very late — never wait for a lost pulse. Diagnosis is CLINICAL; treatment is urgent FASCIOTOMY, and the leg needs all four compartments released, classically through two incisions.
Describe the dermatomes of the foot.FOUR root levels reach the foot — L4, L5, S1 and S2 • L4 — the MEDIAL side of the foot, continuing the strip that comes down over the medial malleolus. Think of the line running down to the medial border of the great toe. Reflex: KNEE JERK (L3, L4) • L5 — the DORSUM of the foot and the GREAT TOE. The classic sign of an L5 root lesion is weakness of EXTENSOR HALLUCIS LONGUS — the patient cannot hold the big toe up against resistance. NO reflex tests L5 • S1 — the LATERAL BORDER of the foot, the LITTLE TOE, the HEEL and the SOLE. Reflex: ANKLE JERK (S1, S2) • S2 — a strip up the back of the leg and the heel • NOW CONTRAST THAT WITH THE PERIPHERAL NERVES, because the examiner will almost always follow up with it • SAPHENOUS (femoral) — medial side of the foot as far as the base of the great toe. The only nerve BELOW the knee that is not from the sciatic • SUPERFICIAL PERONEAL — most of the DORSUM of the foot and toes • DEEP PERONEAL — the FIRST WEB SPACE only. That small triangle is its autonomous zone and is the single most useful test of the nerve • SURAL — the LATERAL border of the foot and the little toe • MEDIAL and LATERAL PLANTAR (from the tibial) — the SOLE • MEDIAL CALCANEAL (from the tibial) — the HEEL, which is why heel sensation is spared in tarsal tunnel syndrome; the branch comes off ABOVE the flexor retinaculum • THE DISTINCTION THAT MATTERS: numbness of the dorsum in a strip is a ROOT problem; numbness of the whole dorsum sparing the web space is SUPERFICIAL PERONEAL; numbness confined to the first web space is DEEP PERONEAL.
Identify the pyloric plane on this subject.THE TRANSPYLORIC PLANE OF ADDISON — a horizontal plane at the level of the LOWER BORDER OF THE BODY OF L1 • HOW TO FIND IT ON A LIVING SUBJECT, and give more than one method • MIDWAY between the JUGULAR (suprasternal) NOTCH and the UPPER BORDER OF THE PUBIC SYMPHYSIS — the most reliable • or roughly a HAND'S BREADTH below the XIPHISTERNAL JOINT • or midway between the xiphisternum and the umbilicus, which is quicker but cruder • WHAT LIES IN IT — this is the real question • the PYLORUS of the stomach (variable, and it moves with posture and with a meal) • the FUNDUS OF THE GALLBLADDER, at the tip of the 9th COSTAL CARTILAGE where the lateral border of the right rectus sheath crosses the costal margin • the NECK and BODY of the PANCREAS • the DUODENOJEJUNAL FLEXURE • the HILA OF BOTH KIDNEYS — the LEFT hilum is in the plane, the RIGHT lies a little BELOW it, because the right kidney is pushed down by the liver • the ORIGIN OF THE SUPERIOR MESENTERIC ARTERY • the FORMATION OF THE PORTAL VEIN behind the neck of the pancreas • the ROOT OF THE TRANSVERSE MESOCOLON • the HILUM OF THE SPLEEN • the TERMINATION OF THE SPINAL CORD (conus medullaris, L1/L2) • the 9th COSTAL CARTILAGE on each side • ONE MORE PLANE WORTH KNOWING: the TRANSTUBERCULAR (supracristal) plane at L5, drawn between the tubercles of the iliac crests — with two vertical midinguinal lines these divide the abdomen into the nine regions.
This axial section is taken at the level of the pyloric plane. Is it being viewed from below upwards, or from above downwards?It is viewed FROM BELOW LOOKING UPWARDS — from the patient's feet towards the head. That is the UNIVERSAL convention for axial sections and for CT and MRI • THE CONSEQUENCE: the patient's RIGHT side appears on the LEFT of the image, and the patient's LEFT appears on the RIGHT. You are, in effect, standing at the end of the bed looking up at the patient • HOW TO PROVE IT ON THE SPECIMEN, rather than assert it — give the examiner landmarks • find the LIVER: its bulk is the RIGHT lobe, and it should appear on the LEFT of the image • find the STOMACH and SPLEEN: they are left-sided structures and should appear on the RIGHT of the image • find the great vessels: the IVC lies to the RIGHT of the AORTA in the body, so on the image the IVC sits to the LEFT of the aorta, and it is the thin-walled oval one • the RIGHT KIDNEY sits LOWER than the left, so at L1 you may catch more of the left kidney than the right • WHY IT MATTERS: getting the side wrong on a CT is how the wrong kidney gets removed. In the station, say the convention, then confirm it from a structure — the liver is the easiest.
Identify the following on this axial prosection: the right lobe of the liver, the inferior vena cava, the right kidney, the body of the stomach and the pyloric antrum.Remember you are looking from BELOW, so the patient's right is on your left • RIGHT LOBE OF THE LIVER — the large solid mass filling the anterior and right part of the section, on the LEFT of the image. Its posterior surface is moulded around the IVC • INFERIOR VENA CAVA — a thin-walled, oval, often collapsed vessel lying POSTERIOR, in its groove on the back of the liver, immediately to the RIGHT of the AORTA in the body. The aorta is the smaller, rounder, thicker-walled one just to the left of it and in front of the vertebral body • RIGHT KIDNEY — RETROPERITONEAL, posterolateral on the image-left, surrounded by bright PERIRENAL FAT within the renal fascia, lying on psoas and quadratus lumborum. At L1 you often see only its upper pole because the liver pushes the right kidney down • BODY OF THE STOMACH — anteriorly on the image-RIGHT (the patient's left), a thick-walled hollow viscus with rugal folds • PYLORIC ANTRUM — the distal part of the stomach, which sweeps back across the MIDLINE to the RIGHT at this level, on its way to the pylorus. So at the transpyloric plane you may see stomach on BOTH sides of the midline — body on the left, antrum crossing to the right • WORK SYSTEMATICALLY: name the vertebra, then the great vessels, then the solid organs, then the hollow ones, then the muscles of the wall. Never start by guessing at the smallest structure.
Name the space between the abdominal wall and the liver, and the space behind the stomach.IN FRONT OF AND ABOVE THE LIVER — the SUBPHRENIC (subdiaphragmatic) SPACE, between the diaphragm and anterior abdominal wall and the diaphragmatic surface of the liver. It is divided into RIGHT and LEFT by the FALCIFORM LIGAMENT • BELOW AND BEHIND THE RIGHT LOBE — the RIGHT SUBHEPATIC SPACE, better known as the HEPATORENAL POUCH OF MORISON, between the visceral surface of the right lobe of the liver and the upper pole of the right kidney. In a SUPINE patient this is the MOST DEPENDENT part of the upper peritoneal cavity, so blood, pus and bile collect here — which is why it is a standard FAST scan window and the commonest site of a subphrenic abscess • BEHIND THE STOMACH — the LESSER SAC, also called the OMENTAL BURSA. It lies behind the stomach and the lesser omentum and in front of the pancreas and the structures of the stomach bed • IT COMMUNICATES with the greater sac through ONE opening: the EPIPLOIC FORAMEN (of WINSLOW). Know its four boundaries • ANTERIOR — the free right edge of the LESSER OMENTUM, carrying the portal triad: BILE DUCT to the right, HEPATIC ARTERY to the left, PORTAL VEIN behind • POSTERIOR — the INFERIOR VENA CAVA • SUPERIOR — the CAUDATE LOBE of the liver • INFERIOR — the FIRST PART OF THE DUODENUM • CLINICALLY: a finger in the foramen with the thumb in front is PRINGLE'S MANOEUVRE, which compresses the hepatic artery and portal vein to control bleeding from the liver; if bleeding continues despite it, suspect the hepatic veins or the IVC.
Locate the gallbladder on this subject.The FUNDUS OF THE GALLBLADDER lies at the TIP OF THE 9TH COSTAL CARTILAGE, at the point where the LATERAL BORDER OF THE RIGHT RECTUS ABDOMINIS crosses the COSTAL MARGIN • Two other ways of saying the same point, both acceptable • at the intersection of the TRANSPYLORIC PLANE with the right lateral border of the rectus sheath • approximately where the RIGHT MIDCLAVICULAR LINE meets the COSTAL MARGIN • SHOW IT PROPERLY: put a finger on the xiphisternum, run laterally and down along the costal margin until you meet the lateral edge of rectus abdominis — ask the subject to tense the abdomen and the edge becomes obvious — and stop there • THE ANATOMY BEHIND THE SURFACE MARK: the gallbladder lies in a fossa on the VISCERAL SURFACE of the RIGHT lobe of the liver, between the right lobe and the QUADRATE lobe. It is in contact with the first and second parts of the DUODENUM and with the TRANSVERSE COLON • Its fundus projects just BEYOND the inferior border of the liver, which is why it can be palpated when it is distended and why it is the point of contact in Murphy's sign • A normal gallbladder is NOT palpable. COURVOISIER'S LAW: in the presence of painless jaundice, a palpable gallbladder is unlikely to be due to stones — a chronically inflamed, stone-bearing gallbladder is fibrosed and cannot distend, so think malignant obstruction of the distal bile duct.
Run your fingers down along the costal cartilage as far as the anterior midclavicular line. What organ lies underneath?The GALLBLADDER — specifically its FUNDUS, lying just beneath the costal margin at the tip of the 9th costal cartilage, where the lateral border of the right rectus crosses it • Immediately deep and above it is the RIGHT LOBE OF THE LIVER, in whose fossa the gallbladder sits; behind it are the first and second parts of the DUODENUM and the TRANSVERSE COLON • THIS IS EXACTLY HOW MURPHY'S SIGN IS ELICITED, and that is why the examiner asks in this way • Place your fingers at that point, pressing gently under the costal margin • Ask the patient to TAKE A DEEP BREATH IN • The diaphragm descends and pushes the liver and the inflamed gallbladder DOWN ONTO your fingers • A POSITIVE sign is when the patient CATCHES THEIR BREATH and stops inspiration because of the pain • It must be NEGATIVE ON THE LEFT to count — that is the part candidates forget • It is a sign of ACUTE CHOLECYSTITIS, not of biliary colic, and it is unreliable in the elderly • The ultrasound equivalent — the SONOGRAPHIC MURPHY'S SIGN, tenderness maximal directly over the gallbladder as seen on the probe — is more specific than the clinical one • Note the referred pain: the gallbladder is foregut, so visceral pain is felt in the EPIGASTRIUM; when the parietal peritoneum and the diaphragm become involved, pain is referred to the RIGHT SHOULDER TIP through the PHRENIC NERVE (C3, C4, C5).
A patient is stabbed in the epigastrium, the blade travelling from below upwards. What structures are at risk?ANSWER IN LAYERS FIRST, then contents — that is what separates a good answer from a list • THE WALL, in the midline: skin, superficial fascia (CAMPER'S fatty layer then SCARPA'S membranous layer), LINEA ALBA, transversalis fascia, extraperitoneal fat, parietal peritoneum. Off the midline you pass instead through the ANTERIOR RECTUS SHEATH, RECTUS ABDOMINIS with the SUPERIOR EPIGASTRIC VESSELS behind it, then the posterior sheath • THEN, ANGLED UPWARDS, THE STRUCTURES AT RISK • LEFT LOBE OF THE LIVER — lies directly behind the epigastrium and is the commonest organ injured here • STOMACH — body, lesser curve and pyloric antrum • LESSER OMENTUM and, through it, the LESSER SAC • TRANSVERSE COLON and GREATER OMENTUM • DIAPHRAGM — and this is the critical one. The diaphragm rises to about the 4th intercostal space in full expiration, so an upward blade from the epigastrium enters the CHEST • PERICARDIUM and the RIGHT VENTRICLE — the subxiphoid route is the classic path to the heart, and CARDIAC TAMPONADE is the immediate threat • PLEURA and the LUNG BASE, risking haemothorax or pneumothorax • Deeper still: PANCREAS, COELIAC TRUNK and its branches, AORTA, IVC and the portal vein • THE PRINCIPLE TO STATE: any penetrating wound between the NIPPLES and the COSTAL MARGIN is a THORACOABDOMINAL wound and must be assumed to have crossed the diaphragm until proven otherwise. Diaphragmatic injury is easily missed and presents years later as a diaphragmatic hernia • MANAGEMENT: ATLS primary survey, and never probe or remove an impaled object outside theatre.
What are the boundaries of the quadrate and caudate lobes?Both sit on the VISCERAL (posteroinferior) surface, within the H-SHAPED arrangement of fissures. Draw the H in the air as you speak: right limb, left limb, crossbar • THE H • RIGHT LIMB — the FOSSA FOR THE GALLBLADDER in front and the GROOVE FOR THE IVC behind • LEFT LIMB — the FISSURE FOR THE LIGAMENTUM TERES in front and the FISSURE FOR THE LIGAMENTUM VENOSUM behind • CROSSBAR — the PORTA HEPATIS • QUADRATE LOBE (Couinaud segment IVb) — the area IN FRONT OF the porta • RIGHT: fossa for the gallbladder • LEFT: fissure for the ligamentum teres • BEHIND/ABOVE: the porta hepatis • IN FRONT/BELOW: the sharp inferior border of the liver • It is related to the pylorus, the first part of the duodenum and the transverse colon • CAUDATE LOBE (Couinaud segment I) — the area BEHIND the porta • RIGHT: the groove for the IVC • LEFT: the fissure for the ligamentum venosum • BELOW/IN FRONT: the porta hepatis • ABOVE: continuous with the diaphragmatic surface at the bare area • It has two processes — the PAPILLARY PROCESS, and the CAUDATE PROCESS which runs to the right to join the right lobe and forms the UPPER BOUNDARY OF THE EPIPLOIC FORAMEN • The caudate lobe lies in the posterior wall of the LESSER SAC, with the lesser omentum attached along the fissure for the ligamentum venosum.
What is the blood supply to the quadrate lobe?The LEFT HEPATIC ARTERY, with the LEFT BRANCH OF THE PORTAL VEIN — and its bile drains into the LEFT HEPATIC DUCT • WHY THAT IS THE INTERESTING ANSWER: the quadrate lobe lies to the RIGHT of the falciform ligament and the fissure for the ligamentum teres, so by the old ANATOMICAL description it belongs to the RIGHT lobe. But FUNCTIONALLY it belongs to the LEFT LIVER. It is COUINAUD SEGMENT IVb — part of the left hemiliver • THE PRINCIPLE: the liver is divided functionally not by its surface ligaments but by the distribution of the PORTAL TRIADS and the HEPATIC VEINS. Segments are defined by portal inflow and separated by hepatic veins • THE CAUDATE LOBE (segment I) IS THE EXCEPTION and the examiner will very likely ask it next: it receives arterial and portal blood from BOTH the right and left branches, and it drains its venous blood DIRECTLY into the IVC through several small veins rather than through the three main hepatic veins • That independence is why the caudate lobe HYPERTROPHIES in BUDD-CHIARI SYNDROME, when the main hepatic veins are obstructed but the caudate's own outflow remains patent — a classic radiological sign • Practical consequence: in a LEFT hepatectomy, segment IVb goes with the left liver; the resection line is CANTLIE'S LINE, not the falciform ligament.
What structure separates the right and left lobes of the liver?There are TWO answers and the examiner wants BOTH, because they do not describe the same line • ANATOMICAL (morphological) DIVISION — the FALCIFORM LIGAMENT on the anterosuperior surface, continued on the visceral surface by the FISSURE FOR THE LIGAMENTUM TERES in front and the FISSURE FOR THE LIGAMENTUM VENOSUM behind. This is what you can see, and it is what the old anatomists described. By this division the QUADRATE and CAUDATE lobes lie in the RIGHT lobe • FUNCTIONAL (surgical) DIVISION — CANTLIE'S LINE, an imaginary plane running from the FUNDUS OF THE GALLBLADDER anteriorly to the INFERIOR VENA CAVA posteriorly. The MIDDLE HEPATIC VEIN lies in this plane • It divides the liver into a true RIGHT and LEFT HEMILIVER, each with its own hepatic artery, portal vein branch and bile duct — so each can be removed independently • BY THIS DIVISION the QUADRATE lobe (segment IVb) belongs to the LEFT liver, and the CAUDATE lobe (segment I) is autonomous, belonging to neither • SAY IT PLAINLY: the falciform ligament is a surface landmark that does NOT correspond to any vascular boundary. It is the wrong line to cut along. All modern liver surgery uses Cantlie's line and the COUINAUD segments — eight segments numbered anticlockwise as seen from the front, with segment I the caudate.
What is the structure being pointed at?The QUADRATE LOBE of the liver • WHAT TO SAY AS YOU IDENTIFY IT: it is the roughly RECTANGULAR area on the VISCERAL surface of the liver, lying IN FRONT OF the PORTA HEPATIS, bounded on the RIGHT by the FOSSA FOR THE GALLBLADDER, on the LEFT by the FISSURE FOR THE LIGAMENTUM TERES, and in front by the sharp inferior border of the liver • It is COUINAUD SEGMENT IVb • RELATIONS: the PYLORUS, the FIRST PART OF THE DUODENUM and the TRANSVERSE COLON lie against it • THE POINT TO MAKE UNPROMPTED, because it is what the examiner is fishing for: although it lies to the RIGHT of the falciform ligament and therefore in the anatomical right lobe, it is FUNCTIONALLY PART OF THE LEFT LIVER — supplied by the LEFT hepatic artery and the LEFT branch of the portal vein, and draining into the LEFT hepatic duct • Do not confuse it with the CAUDATE lobe, which lies BEHIND the porta hepatis, between the fissure for the ligamentum venosum and the groove for the IVC.
Identify the following on this posterior view of the liver: the quadrate lobe, the caudate lobe, the fissure for the ligamentum teres, the falciform ligament, the IVC, the portal vein, the hepatic artery and the common bile duct.ORIENT FIRST by finding the H • RIGHT LIMB of the H: GALLBLADDER FOSSA in front, GROOVE FOR THE IVC behind • LEFT LIMB: FISSURE FOR THE LIGAMENTUM TERES in front, FISSURE FOR THE LIGAMENTUM VENOSUM behind • CROSSBAR: the PORTA HEPATIS • NOW NAME THEM • QUADRATE LOBE — in the front limb of the H, between the gallbladder fossa and the fissure for the ligamentum teres, IN FRONT of the porta. Segment IVb • CAUDATE LOBE — in the back limb, between the IVC groove and the fissure for the ligamentum venosum, BEHIND the porta. Segment I • FISSURE FOR THE LIGAMENTUM TERES — the anterior part of the left sagittal fissure. It contains the LIGAMENTUM TERES, the obliterated LEFT UMBILICAL VEIN, running from the umbilicus to the left branch of the portal vein • FALCIFORM LIGAMENT — the sickle-shaped peritoneal fold running UP from that fissure onto the anterosuperior surface, with the ligamentum teres in its free lower edge • INFERIOR VENA CAVA — in its deep groove on the posterior surface, at the right margin of the caudate lobe, receiving the three hepatic veins just below the diaphragm • THE PORTA HEPATIS — the transverse fissure. Its contents FROM FRONT TO BACK are: right and left HEPATIC DUCTS, then the HEPATIC ARTERY branches, then the PORTAL VEIN, which is the most POSTERIOR. Mnemonic: DAV — Duct, Artery, Vein • IN THE FREE EDGE OF THE LESSER OMENTUM the same three arrange themselves as: COMMON BILE DUCT to the RIGHT, HEPATIC ARTERY to the LEFT, PORTAL VEIN BEHIND them both. That free edge is the anterior boundary of the epiploic foramen • The porta also transmits lymphatics and the hepatic nerve plexus.
Describe the venous drainage of the liver.Be clear from the first sentence that the PORTAL VEIN brings blood IN and the HEPATIC VEINS take it OUT — conflating the two is the commonest error • THE PATHWAY THROUGH THE LIVER: portal venules and hepatic arterioles empty into the SINUSOIDS, which drain to the CENTRAL VEIN of each lobule, then to SUBLOBULAR veins, then to the HEPATIC VEINS • THE THREE HEPATIC VEINS drain directly into the INFERIOR VENA CAVA, just below the diaphragm, over a very short course — which is why they are so difficult to control surgically • RIGHT HEPATIC VEIN — between the right anterior and right posterior sectors • MIDDLE HEPATIC VEIN — runs in CANTLIE'S LINE, between the right and left hemilivers • LEFT HEPATIC VEIN — between segments II and III. The middle and left commonly join to form a COMMON TRUNK before entering the IVC • They are INTERSEGMENTAL — they run BETWEEN segments, whereas the portal triads run WITHIN them. That is the key to segmental liver resection • PLUS: several small veins from the CAUDATE LOBE (segment I) draining STRAIGHT into the IVC, independent of the three main veins • THE INFLOW, for completeness: the PORTAL VEIN carries about 75-80% of the liver's blood, formed BEHIND THE NECK OF THE PANCREAS at L1 by the union of the SPLENIC and SUPERIOR MESENTERIC veins. The hepatic artery supplies the remaining 20-25% of the blood but about half the oxygen • CLINICAL • BUDD-CHIARI SYNDROME — hepatic venous outflow obstruction, with caudate lobe hypertrophy because its own veins stay patent • PORTAL HYPERTENSION opens PORTO-SYSTEMIC ANASTOMOSES: oesophageal varices, caput medusae at the umbilicus through recanalised paraumbilical veins, rectal varices, and retroperitoneal channels.
Identify the falciform ligament on this anterior view of the liver. What does it connect, and what is it made of?IDENTIFY IT: the SICKLE-SHAPED (falciform means sickle-shaped) fold running in the SAGITTAL plane on the ANTEROSUPERIOR surface of the liver, from the UMBILICUS upwards and backwards • WHAT IT CONNECTS: the liver to the ANTERIOR ABDOMINAL WALL and to the UNDERSURFACE OF THE DIAPHRAGM • WHAT IT IS MADE OF: a DOUBLE LAYER OF PERITONEUM — it is not a true ligament at all. It is the remnant of the VENTRAL MESOGASTRIUM, derived from the SEPTUM TRANSVERSUM • ITS FREE LOWER BORDER contains the LIGAMENTUM TERES (round ligament of the liver) — the obliterated LEFT UMBILICAL VEIN — together with the PARAUMBILICAL VEINS, which connect the portal system to the systemic veins of the abdominal wall • WHAT HAPPENS TO ITS TWO LAYERS SUPERIORLY: they separate. The RIGHT layer becomes the UPPER LAYER OF THE CORONARY LIGAMENT; the LEFT layer becomes the LEFT TRIANGULAR LIGAMENT • WHY IT MATTERS • it divides the SUBPHRENIC SPACE into RIGHT and LEFT compartments, which determines where a subphrenic abscess collects • it marks the ANATOMICAL but NOT the functional division of the liver — the surgical line is Cantlie's line, further to the right • in PORTAL HYPERTENSION the paraumbilical veins in its edge recanalise and produce CAPUT MEDUSAE • it is the landmark for the ligamentum teres approach in liver surgery, and it must be divided to mobilise the liver • It is also occasionally the cause of a rare internal hernia or of adhesive obstruction after laparoscopy.
What are the attachments of the liver to the diaphragm?All of them are PERITONEAL REFLECTIONS, and they surround one area where there is NO peritoneum at all • CORONARY LIGAMENT — the principal attachment. The peritoneum of the diaphragm reflects onto the diaphragmatic surface of the right lobe as an UPPER and a LOWER layer, which are widely separated. Between them lies the BARE AREA OF THE LIVER, where the liver is in DIRECT CONTACT with the diaphragm with no peritoneum intervening. The IVC lies at its left margin • RIGHT TRIANGULAR LIGAMENT — formed where the upper and lower layers of the coronary ligament MEET at the right extremity of the bare area • LEFT TRIANGULAR LIGAMENT — a two-layered fold on the superior surface of the LEFT lobe, running to the diaphragm; its right end is continuous with the left layer of the falciform ligament, and its free left end is the APPENDIX FIBROSA HEPATIS • FALCIFORM LIGAMENT — anteriorly, to the diaphragm and to the anterior abdominal wall down to the umbilicus • The IVC, in its groove on the posterior surface, is bound to the diaphragm at the caval opening (T8), and the hepatic veins enter it there — a further, and very strong, fixation • FOR COMPLETENESS, the attachment that is NOT to the diaphragm: the LESSER OMENTUM, running from the fissure for the ligamentum venosum and the porta hepatis down to the lesser curvature of the stomach and the first part of the duodenum • CLINICAL POINTS • the liver MOVES WITH RESPIRATION because it is slung from the diaphragm — that is why you palpate the liver edge on inspiration, and why Murphy's sign works • infection in the bare area can track directly through the diaphragm to the pleura • these ligaments must be divided to mobilise the liver for resection or transplantation, and the bare area is a site of troublesome bleeding in liver trauma.
Identify the abdominal aorta. Give its vertebral levels and its surface markings.THE COURSE • BEGINS at the AORTIC HIATUS of the diaphragm at the level of T12 — passing behind the MEDIAN ARCUATE LIGAMENT, between the two crura. Because it is behind the ligament and not through muscle, the aorta is NOT compressed during respiration • DESCENDS slightly to the LEFT of the midline, on the front of the vertebral bodies • ENDS by dividing into the two COMMON ILIAC ARTERIES at the level of L4 • SURFACE MARKING: a band about 2 cm wide, from the median plane at the level of the transpyloric plane down to a point about 1 cm BELOW and slightly to the LEFT of the UMBILICUS. L4 also corresponds to the SUPRACRISTAL PLANE — the line joining the highest points of the iliac crests • THE LEVELS TO HAVE READY • DIAPHRAGMATIC OPENINGS: IVC at T8, OESOPHAGUS at T10, AORTA at T12. Mnemonic: "I ate ten eggs at twelve" • COELIAC TRUNK T12 • SUPERIOR MESENTERIC ARTERY L1 • RENAL ARTERIES L1-L2 • GONADAL ARTERIES L2 • INFERIOR MESENTERIC ARTERY L3 • BIFURCATION L4 • The COMMON ILIAC ARTERIES then divide at L5/S1, in front of the sacroiliac joint, into internal and external iliac • THE IVC FOR CONTRAST: formed at L5 — LOWER than the aortic bifurcation — and pierces the diaphragm at T8, so the vena cava's span is L5 to T8 while the aorta's is T12 to L4 • CLINICALLY: you palpate an aortic aneurysm just above and to the left of the umbilicus, and you feel for EXPANSILE, not merely pulsatile, movement.
Identify the branches of the aorta that supply the gastrointestinal tract.THREE UNPAIRED ANTERIOR (midline) BRANCHES, one for each embryological division of the gut • COELIAC TRUNK — T12, immediately below the hiatus. Supplies the FOREGUT: lower oesophagus, stomach, the duodenum as far as the MAJOR DUODENAL PAPILLA in the second part, plus the liver, gallbladder, spleen and most of the pancreas. THREE BRANCHES: LEFT GASTRIC, SPLENIC and COMMON HEPATIC • SUPERIOR MESENTERIC ARTERY — L1, about 1 cm below the coeliac. Supplies the MIDGUT: from the major papilla to the junction of the PROXIMAL TWO-THIRDS and DISTAL THIRD OF THE TRANSVERSE COLON. Branches: inferior pancreaticoduodenal, jejunal and ileal branches, MIDDLE COLIC, RIGHT COLIC and ILEOCOLIC • INFERIOR MESENTERIC ARTERY — L3. Supplies the HINDGUT: the distal third of the transverse colon to the upper anal canal, down to the PECTINATE LINE. Branches: LEFT COLIC, SIGMOID branches and SUPERIOR RECTAL • THE ANASTOMOSES, which is where the marks are • the MARGINAL ARTERY OF DRUMMOND runs along the whole mesenteric border of the colon linking all the colic arteries • the ARC OF RIOLAN is a more central, inconstant connection between middle colic and left colic • TWO WATERSHEDS: the SPLENIC FLEXURE (Griffiths' point, SMA/IMA junction) and the RECTOSIGMOID (Sudeck's point) — the classic sites of ISCHAEMIC COLITIS • REFERRED PAIN follows the same three divisions: foregut to the EPIGASTRIUM, midgut to the UMBILICUS, hindgut to the SUPRAPUBIC region. That is why appendicitis begins centrally and moves.
Identify the posterior branches of the aorta.Classify the whole aorta first — it makes the posterior branches obvious and it is what the examiner is testing • ANTERIOR, UNPAIRED, VISCERAL: coeliac (T12), superior mesenteric (L1), inferior mesenteric (L3) — the gut • LATERAL, PAIRED, VISCERAL: MIDDLE SUPRARENAL (L1), RENAL (L1-L2), GONADAL (testicular or ovarian, L2) • POSTERIOR, PAIRED, PARIETAL — these are the ones asked for • INFERIOR PHRENIC ARTERIES, the FIRST branches of the abdominal aorta, arising at T12 just below the hiatus. Each gives the SUPERIOR SUPRARENAL arteries • FOUR PAIRS OF LUMBAR ARTERIES, from L1 to L4, running backwards and laterally around the vertebral bodies deep to the psoas — the exact serial equivalent of the posterior intercostal arteries. They supply the vertebrae, spinal cord, the muscles of the back and the abdominal wall • POSTERIOR, UNPAIRED, TERMINAL: the MEDIAN SACRAL ARTERY, a single small vessel from the BACK of the aorta just ABOVE the bifurcation, running down over L5 and the sacrum. It is the persisting continuation of the primitive dorsal aorta • A FIFTH LUMBAR pair, when present, usually comes from the median sacral or the iliolumbar artery • SURGICAL RELEVANCE: the LUMBAR ARTERIES BLEED BRISKLY from the back of an aneurysm sac during open AAA repair and must be under-run from inside the sac; and they are the source of TYPE II ENDOLEAK after EVAR, filling the sac retrogradely.
Describe the tributaries of the inferior vena cava.FORMATION AND COURSE: formed by the union of the two COMMON ILIAC VEINS at L5, to the RIGHT of the midline and BELOW the aortic bifurcation. It ascends on the right of the vertebral bodies, grooves the bare area of the liver, pierces the CENTRAL TENDON of the diaphragm at T8, and enters the RIGHT ATRIUM • TRIBUTARIES, FROM BELOW UPWARDS • the two COMMON ILIAC VEINS (its formation) • the MEDIAN SACRAL vein • the THIRD and FOURTH LUMBAR VEINS directly; the upper two drain into the ASCENDING LUMBAR VEIN, which becomes the AZYGOS on the right and the HEMIAZYGOS on the left • the RIGHT GONADAL VEIN • the RENAL VEINS at L1-L2 • the RIGHT SUPRARENAL VEIN • the RIGHT INFERIOR PHRENIC VEIN • the THREE HEPATIC VEINS, immediately below the diaphragm • THE ASYMMETRY IS THE EXAM POINT: on the LEFT, the gonadal, suprarenal and inferior phrenic veins do NOT reach the IVC. They drain into the LEFT RENAL VEIN, which is longer and crosses ANTERIOR to the aorta and POSTERIOR to the superior mesenteric artery to reach the cava • CONSEQUENCES • a LEFT VARICOCELE is commoner, because the left testicular vein enters the renal vein at a right angle and has a longer column of blood; a NEW left varicocele in an older man raises the question of a renal cell carcinoma obstructing the renal vein • NUTCRACKER SYNDROME — compression of the left renal vein between the aorta and the SMA • SAY THIS UNPROMPTED: the IVC receives NO tributary from the gastrointestinal tract. That venous blood goes to the PORTAL VEIN and through the liver first.
What structures pass in front of the abdominal aorta?Work from above downwards and name them in order — a list in the right sequence sounds like knowledge, a list in any order sounds like recall • the COELIAC TRUNK and the COELIAC PLEXUS and GANGLIA, draped over its origin • the LESSER SAC and, through it, the STOMACH • the BODY OF THE PANCREAS with the SPLENIC VEIN behind it • the LEFT RENAL VEIN, crossing from left to right to reach the IVC, passing IN FRONT of the aorta and BEHIND the superior mesenteric artery • the THIRD (horizontal) PART OF THE DUODENUM, crossing at L3 in the same angle • the ROOT OF THE MESENTERY and the SUPERIOR MESENTERIC VESSELS • coils of SMALL INTESTINE and the peritoneum • the LEFT COMMON ILIAC VEIN crosses behind the RIGHT common iliac artery just below the bifurcation • TWO SYNDROMES COME STRAIGHT OUT OF THIS LIST, and the examiner is usually heading for one of them • SUPERIOR MESENTERIC ARTERY (WILKIE'S) SYNDROME — the THIRD part of the duodenum compressed in the AORTOMESENTERIC ANGLE between the SMA in front and the aorta behind. The angle is normally 25-60 degrees and is held open by the fat pad in the mesenteric root; rapid weight loss, a body cast or scoliosis surgery narrows it, giving postprandial vomiting relieved by lying prone or on the left side • NUTCRACKER SYNDROME — the LEFT RENAL VEIN compressed in the same angle, causing left flank pain, haematuria and a left varicocele.
Identify the branches of the aorta on this angiogram of the abdominal aorta.Orient first: the AORTA runs vertically in the midline, slightly LEFT, and this is an ANTEROPOSTERIOR projection, so the patient's RIGHT is on your LEFT • WHAT YOU CAN SEE • the RENAL ARTERIES at L1-L2, arising laterally at roughly a right angle. The RIGHT renal artery is LONGER and passes BEHIND the inferior vena cava; the LEFT is shorter. Note that ACCESSORY (or multiple) RENAL ARTERIES are common — present in about a quarter of people, they are persistent segmental vessels arising directly from the aorta, and they are an END-ARTERY supply, so dividing one infarcts that segment. They matter enormously in transplant donor work-up and in planning EVAR • the AORTIC BIFURCATION at L4 into the two COMMON ILIAC ARTERIES, which then divide at L5/S1 into internal and external iliac • the MEDIAN SACRAL artery continuing in the midline • THE POINT WORTH MAKING UNPROMPTED: the COELIAC TRUNK, SMA and IMA arise from the FRONT of the aorta, so on an AP film they are foreshortened and PROJECT OVER the aortic shadow. To see their origins properly you need a LATERAL projection — that is exactly why a lateral aortogram is taken when mesenteric ischaemia is suspected • Similarly the LUMBAR ARTERIES arise POSTERIORLY and are seen end-on • Look also for the level of the renal arteries relative to any dilatation: whether an aneurysm is INFRARENAL determines whether it can be clamped below the renals or stented with a standard device.
What is this?An ABDOMINAL AORTIC ANEURYSM — an axial contrast-enhanced CT showing a grossly dilated aorta as a large, round, contrast-filled lumen lying anterior and to the LEFT of the vertebral body. Look for low-density crescentic MURAL THROMBUS lining the sac, which is why the true outer diameter is always larger than the flowing lumen • SAY WHERE IT IS: this is INFRARENAL, and about 95% of abdominal aortic aneurysms are. That matters because it allows a clamp below the renal arteries in open repair and a standard infrarenal device at EVAR, whereas a juxtarenal or suprarenal aneurysm needs a fenestrated graft • DEFINITION: an infrarenal aorta of 3 cm or more • SCREENING in the UK (NAAASP): a single ultrasound for men in the year they turn 65. 3.0-4.4 cm annual scans; 4.5-5.4 cm three-monthly; 5.5 cm or more, refer to vascular surgery • INDICATIONS FOR REPAIR: diameter 5.5 cm or more, growth of more than 1 cm in a year, or symptoms • WHY THAT THRESHOLD: below 5.5 cm the annual rupture risk is lower than the operative mortality. Laplace's law explains the behaviour — wall tension rises with radius, so the bigger it is the faster it grows • RUPTURE presents with the triad of ABDOMINAL OR BACK PAIN, HYPOTENSION and a PULSATILE EXPANSILE MASS, and it is the diagnosis in any older patient with collapse and back pain. A retroperitoneal leak may tamponade briefly, which is the window in which to get them to theatre • Do not confuse a normal pulsatile aorta with an aneurysm: an aneurysm is EXPANSILE — your fingers are pushed APART, not merely upward.
Define an aneurysm. What are the causes and risk factors? And define a dissecting aortic aneurysm.DEFINITION: a PERMANENT, LOCALISED DILATATION of an artery to MORE THAN 1.5 TIMES its expected normal diameter, involving ALL THREE LAYERS of the wall. For the infrarenal aorta that means 3 cm or more • TRUE aneurysm — all three layers, intima, media and adventitia. Shape is FUSIFORM (circumferential, the usual aortic type) or SACCULAR (an outpouching from one side, more often mycotic or traumatic) • FALSE (PSEUDO)ANEURYSM — a BREACH in the wall, with the blood contained only by adventitia or surrounding tissue. It is a pulsating haematoma in continuity with the lumen. The everyday example is a femoral pseudoaneurysm after cardiac catheterisation • CAUSES • DEGENERATIVE / ATHEROSCLEROTIC — much the commonest, with elastin and smooth muscle loss, matrix metalloproteinase activity and transmural inflammation • CONNECTIVE TISSUE DISEASE — MARFAN (fibrillin-1), EHLERS-DANLOS type IV (collagen III), Loeys-Dietz • INFECTIVE (mycotic) — Salmonella, Staphylococcus; and SYPHILIS, classically the ascending thoracic aorta • INFLAMMATORY / VASCULITIS — Takayasu, giant cell arteritis, Behcet's • TRAUMATIC, usually producing a false aneurysm • CONGENITAL — berry aneurysms of the circle of Willis • POST-STENOTIC, distal to a coarctation or a cervical rib • RISK FACTORS: increasing AGE, MALE sex (about 6:1), SMOKING — the strongest modifiable factor — a FIRST-DEGREE RELATIVE with an aneurysm, HYPERTENSION, hyperlipidaemia, established atherosclerosis and COPD. DIABETES is NEGATIVELY associated, which is a genuine and quotable oddity • DISSECTING AORTIC ANEURYSM: strictly a MISNOMER, and saying so is worth a mark. An AORTIC DISSECTION is NOT an aneurysm. It is a TEAR IN THE INTIMA that lets blood enter the MEDIA and split it longitudinally, creating a FALSE LUMEN between the inner and outer thirds of the media, which may re-enter the true lumen distally. The vessel may dilate secondarily, which is where the old term came from • CLASSIFICATION — STANFORD A involves the ASCENDING aorta and is a surgical emergency; STANFORD B is confined to the descending aorta distal to the left subclavian and is usually managed medically with tight blood pressure control. DeBakey I, II and III describe the same anatomy • PRESENTATION: sudden TEARING chest or interscapular pain, UNEQUAL pulses and blood pressures between the arms, a widened mediastinum, new aortic regurgitation, and end-organ ischaemia — stroke, myocardial infarction, paraplegia, renal failure, limb ischaemia — depending on which branches are sheared off • RISK FACTORS: HYPERTENSION above all, Marfan, bicuspid aortic valve, coarctation, pregnancy and cocaine.
On this clavicle, identify the upper surface and the sternal and acromial ends. Show how it articulates with the scapula.SIDING IT AND ORIENTING IT — do this out loud • The MEDIAL (STERNAL) END is the LARGER, rounded, quadrilateral end. The LATERAL (ACROMIAL) END is FLATTENED from above downwards and thinner • The SHAFT is CONVEX FORWARDS in its MEDIAL TWO-THIRDS and CONCAVE FORWARDS in its LATERAL THIRD — the S-shape • THE UPPER SURFACE is SMOOTH and SUBCUTANEOUS, covered only by platysma. THE UNDER SURFACE is ROUGH, and that roughness tells you which way is down: the IMPRESSION FOR THE COSTOCLAVICULAR LIGAMENT medially, the SUBCLAVIAN GROOVE for subclavius in the middle third, and laterally the CONOID TUBERCLE and TRAPEZOID LINE for the coracoclavicular ligament • So: rough side DOWN, flat thin end LATERALLY, medial two-thirds convex forwards — and the side it points to is the side of the body • THE ARTICULATIONS • MEDIALLY, the STERNOCLAVICULAR JOINT with the manubrium and the first costal cartilage — a SADDLE-type synovial joint with a complete INTRA-ARTICULAR DISC. It is the ONLY TRUE JOINT between the upper limb and the axial skeleton • LATERALLY, the ACROMIOCLAVICULAR JOINT with the ACROMION of the scapula — a PLANE synovial joint with a fibrocartilaginous disc. Demonstrate it by placing the flattened lateral end against the medial edge of the acromion, with the clavicle overriding it slightly • STABILITY OF THE AC JOINT • the ACROMIOCLAVICULAR ligaments resist ANTEROPOSTERIOR translation • the CORACOCLAVICULAR ligament — CONOID medially, TRAPEZOID laterally — resists VERTICAL translation and is the true suspensory ligament of the upper limb • CLINICAL • the clavicle is the FIRST bone to ossify and the ONLY long bone to ossify IN MEMBRANE, and its medial epiphysis is the LAST in the body to fuse, at about 25 • Fracture is commonest at the JUNCTION OF THE MIDDLE AND LATERAL THIRDS: the medial fragment is pulled UP by sternocleidomastoid and the lateral fragment DOWN by the weight of the limb. Beneath lie the subclavian vessels, the brachial plexus and the lung apex.
Identify the spine of the scapula, the acromion and the coracoid process.SPINE OF THE SCAPULA — the triangular shelf projecting from the upper part of the DORSAL surface, dividing it into the SUPRASPINOUS and INFRASPINOUS fossae. Its posterior crest is SUBCUTANEOUS and easily palpable; it meets the medial border at the level of the T3 SPINOUS PROCESS. TRAPEZIUS inserts into its upper border and crest; DELTOID arises from its lower border and crest — so the crest gives attachment to both, one above and one below • ACROMION — the flattened lateral continuation of the spine, forming the POINT OF THE SHOULDER and the highest lateral bony landmark. It carries a facet on its medial edge for the clavicle. It gives origin to DELTOID and insertion to part of trapezius. With the CORACOID and the CORACOACROMIAL LIGAMENT stretched between them, it forms the CORACOACROMIAL ARCH — the roof of the SUBACROMIAL SPACE, beneath which the supraspinatus tendon and the subacromial bursa glide. This is where IMPINGEMENT occurs. BIGLIANI types: I flat, II curved, III HOOKED — type III being most associated with cuff disease • CORACOID PROCESS — the hook-shaped process from the upper border, running first upwards and then forwards and laterally. Palpate it about 2.5 cm BELOW the junction of the middle and lateral thirds of the clavicle, in the floor of the DELTOPECTORAL TRIANGLE — press firmly, it is deep • It has been called the LIGHTHOUSE OF THE SHOULDER because it guides you to everything: THREE MUSCLES attach (pectoralis minor inserting, coracobrachialis and the SHORT HEAD OF BICEPS arising as the conjoint tendon) and THREE LIGAMENTS (coracoclavicular, coracoacromial, coracohumeral) • Just MEDIAL to the coracoid is the SUPRASCAPULAR NOTCH, bridged by the superior transverse scapular ligament: the NERVE runs UNDER the ligament, the ARTERY OVER it — "Army under the bridge, Navy over it".
Identify supraspinatus, infraspinatus and teres minor on this prosection of the posterior shoulder, and describe the origin and insertion of each.All three insert on the GREATER TUBERCLE, in the order they lie — SUPRASPINATUS, INFRASPINATUS, TERES MINOR from ABOVE DOWNWARDS, onto the SUPERIOR, MIDDLE and INFERIOR FACETS. "SIT" • SUPRASPINATUS • ORIGIN: the medial two-thirds of the SUPRASPINOUS FOSSA of the scapula, above the spine • INSERTION: the SUPERIOR facet of the greater tubercle • NERVE: SUPRASCAPULAR (C5, C6) • ACTION: initiates the first 15-20 degrees of ABDUCTION, then assists deltoid; a powerful dynamic stabiliser holding the head in the glenoid • INFRASPINATUS • ORIGIN: the INFRASPINOUS FOSSA, below the spine • INSERTION: the MIDDLE facet • NERVE: SUPRASCAPULAR (C5, C6) • ACTION: LATERAL (external) rotation • TERES MINOR • ORIGIN: the upper two-thirds of the LATERAL BORDER of the scapula, on its dorsal surface • INSERTION: the INFERIOR facet • NERVE: AXILLARY (C5, C6) — the exception, and the detail examiners look for • ACTION: LATERAL rotation and adduction • THE FOURTH MEMBER, in front: SUBSCAPULARIS, from the SUBSCAPULAR FOSSA on the costal surface to the LESSER TUBERCLE, supplied by the UPPER and LOWER SUBSCAPULAR nerves (C5, C6, C7), a MEDIAL rotator • DISTINGUISHING TERES MINOR FROM TERES MAJOR on the specimen, which is the classic trap: teres MINOR is ABOVE, is supplied by the AXILLARY nerve and LATERALLY rotates; teres MAJOR is BELOW, is supplied by the LOWER SUBSCAPULAR nerve and MEDIALLY rotates, inserting into the MEDIAL LIP of the intertubercular groove. The LONG HEAD OF TRICEPS passes between them, separating the TRIANGULAR from the QUADRANGULAR space • THE CUFF AS A WHOLE blends with the capsule and compresses the head into the glenoid, providing the FORCE COUPLE that resists the upward pull of deltoid. Supraspinatus is the commonest tendon to tear, in the hypovascular CRITICAL ZONE about 1 cm from its insertion, giving a PAINFUL ARC between 60 and 120 degrees.
What are the stabilisers of synovial joints in general?Classify them into STATIC and DYNAMIC and the answer organises itself • STATIC (PASSIVE) STABILISERS • BONY CONGRUITY — the shape and depth of the articular surfaces. This is the primary stabiliser of a deep joint like the hip and almost irrelevant in a shallow one like the shoulder • FIBROCARTILAGE — labra, menisci and discs, which deepen the socket and improve congruity • the CAPSULE, and its thickenings • LIGAMENTS — capsular, intracapsular and extracapsular; they are TENSION structures and only work at the end of range, in the direction they are aligned • NEGATIVE INTRA-ARTICULAR PRESSURE and the ADHESION-COHESION of the thin film of synovial fluid, which is a real and often forgotten contribution • DYNAMIC (ACTIVE) STABILISERS • MUSCLES AND THEIR TENDONS crossing the joint. This is the dominant stabiliser of any shallow, mobile joint, and it acts throughout range, not only at the ends • PROPRIOCEPTION — mechanoreceptors in the capsule and ligaments feeding reflex muscle contraction. This is why rehabilitation after a ligament injury is not just about strength • THE PRINCIPLE TO STATE, because it turns a list into an argument: STABILITY AND MOBILITY ARE TRADED AGAINST EACH OTHER. The hip is deep, congruent and stable but limited; the shoulder is shallow and hugely mobile, and pays for it by depending almost entirely on muscle • THE CLINICAL COROLLARY: in a joint that depends on muscle, PROPRIOCEPTIVE AND STRENGTHENING REHABILITATION is a genuine treatment for instability, not an afterthought.
What are the main stabilisers of the shoulder joint?Start with WHY it needs them: the glenohumeral joint is a BALL-AND-SOCKET with a socket only about ONE QUARTER the area of the head, and only about a THIRD of the head in contact at any time — often likened to a golf ball on a tee. It is the most MOBILE and the most FREQUENTLY DISLOCATED joint in the body, and it is stabilised almost entirely by SOFT TISSUE • STATIC STABILISERS • the GLENOID LABRUM, a fibrocartilaginous rim that deepens the socket by roughly 50% • the CAPSULE, lax enough to permit the range • the GLENOHUMERAL LIGAMENTS — SUPERIOR, MIDDLE and INFERIOR. The INFERIOR GLENOHUMERAL LIGAMENT COMPLEX is the most important restraint to ANTERIOR dislocation when the arm is ABDUCTED AND EXTERNALLY ROTATED — the position of throwing, and the position of injury • the CORACOHUMERAL LIGAMENT, resisting INFERIOR translation with the arm at the side • NEGATIVE INTRA-ARTICULAR PRESSURE • the CORACOACROMIAL ARCH above, preventing upward dislocation • DYNAMIC STABILISERS — and these are the MAIN ones • the ROTATOR CUFF: supraspinatus, infraspinatus, teres minor and subscapularis, blending with the capsule and compressing the head into the glenoid • the LONG HEAD OF BICEPS, running through the joint over the head • the SCAPULAR STABILISERS — serratus anterior, trapezius, rhomboids, levator scapulae — providing a stable platform. Scapular dyskinesia causes instability even with a normal cuff • THE WEAK POINT: the capsule is weakest ANTERO-INFERIORLY, where no cuff muscle supports it — which is why over 95% of dislocations are ANTERO-INFERIOR (subcoracoid) • ASSOCIATED LESIONS: a BANKART lesion (anteroinferior labral avulsion) and a HILL-SACHS lesion (posterolateral impaction of the humeral head) • ALWAYS test the AXILLARY NERVE before and after reduction — sensation over the regimental badge area and deltoid contraction.
Identify the greater tuberosity and the anatomical and surgical necks on this humerus.GREATER TUBERCLE (tuberosity) — the LATERAL prominence at the upper end, bearing THREE FACETS for the cuff: SUPERIOR for supraspinatus, MIDDLE for infraspinatus, INFERIOR for teres minor. It is the most lateral bony point of the shoulder and, with deltoid over it, gives the shoulder its ROUNDED CONTOUR — loss of that contour, a SQUARE shoulder, is the sign of dislocation • LESSER TUBERCLE — ANTERIOR, for SUBSCAPULARIS. Between the two runs the INTERTUBERCULAR (BICIPITAL) GROOVE carrying the tendon of the LONG HEAD OF BICEPS, roofed by the transverse humeral ligament. Its LATERAL LIP takes PECTORALIS MAJOR, its MEDIAL LIP TERES MAJOR, and its FLOOR LATISSIMUS DORSI — "a lady between two majors" • ANATOMICAL NECK — the slight groove immediately BELOW THE ARTICULAR MARGIN of the head, separating the head from the two tubercles. It marks the old epiphysial line and gives attachment to the CAPSULE. Fracture here is RARE but serious, because the ARCUATE ARTERY — the terminal branch of the ANTERIOR CIRCUMFLEX HUMERAL — enters the head at this level, so AVASCULAR NECROSIS of the head follows • SURGICAL NECK — the constriction BELOW THE TUBERCLES, where the expanded upper end narrows into the shaft. This is where the humerus COMMONLY fractures, typically in an elderly patient falling on an outstretched hand • WHAT IS AT RISK AT THE SURGICAL NECK: the AXILLARY NERVE and the POSTERIOR CIRCUMFLEX HUMERAL VESSELS, which wind round the bone at exactly this level after passing through the QUADRANGULAR SPACE. So in any surgical neck fracture or shoulder dislocation, TEST DELTOID CONTRACTION AND SENSATION OVER THE REGIMENTAL BADGE AREA, and document it BEFORE reduction • For completeness, the two other nerve-and-level pairings: the RADIAL nerve in the SPIRAL GROOVE with a mid-shaft fracture, and the ULNAR nerve behind the MEDIAL EPICONDYLE with a distal fracture.
Show all the movements of the shoulder joint on yourself.Demonstrate each one, name it, give the range and name the prime movers. Do them in a fixed order so you miss none • FLEXION, 0 to 180 degrees — arm forwards and up. ANTERIOR DELTOID, CLAVICULAR head of PECTORALIS MAJOR, coracobrachialis, biceps • EXTENSION, 0 to about 50-60 degrees — arm backwards. POSTERIOR DELTOID, LATISSIMUS DORSI, TERES MAJOR • ABDUCTION, 0 to 180 degrees — arm out to the side and overhead. SUPRASPINATUS for the first 15-20 degrees, MIDDLE DELTOID to about 90, then SCAPULAR ROTATION by TRAPEZIUS and SERRATUS ANTERIOR for the rest • ADDUCTION, 0 to about 45 degrees across the body. PECTORALIS MAJOR, LATISSIMUS DORSI, TERES MAJOR • MEDIAL (internal) ROTATION, 0 to 90 — elbow tucked in at the side and flexed to 90, hand swung across the abdomen. SUBSCAPULARIS, pectoralis major, latissimus dorsi, teres major, anterior deltoid • LATERAL (external) ROTATION, 0 to 90 — same start position, hand swung outwards. INFRASPINATUS, TERES MINOR, posterior deltoid • CIRCUMDUCTION — the combination, and worth performing to show the joint is multiaxial • SAY THE SCAPULOHUMERAL RHYTHM UNPROMPTED: the first 30 degrees of abduction is purely glenohumeral, and thereafter movement occurs in a 2:1 ratio of GLENOHUMERAL to SCAPULOTHORACIC. So of 180 degrees, roughly 120 is glenohumeral and 60 scapulothoracic • FULL ABDUCTION TO 180 REQUIRES FOUR JOINTS — GLENOHUMERAL, SCAPULOTHORACIC, ACROMIOCLAVICULAR and STERNOCLAVICULAR — plus LATERAL ROTATION of the humerus to swing the greater tubercle out from under the acromion, and some thoracic extension • FUNCTIONAL SCREEN: hand behind the head (abduction and external rotation) and hand behind the back (internal rotation and extension) — Apley's scratch test. A PAINFUL ARC between 60 and 120 degrees points to supraspinatus.
Identify this muscle, and explain the function of its clavicular and its sternal parts.PECTORALIS MAJOR — the large fan-shaped muscle forming the ANTERIOR AXILLARY FOLD • ORIGIN, in three parts • CLAVICULAR HEAD — the medial half of the anterior surface of the CLAVICLE • STERNOCOSTAL HEAD — the anterior surface of the STERNUM and the upper six COSTAL CARTILAGES • ABDOMINAL PART — the aponeurosis of external oblique • INSERTION — the LATERAL LIP OF THE INTERTUBERCULAR (bicipital) GROOVE of the humerus, by a BILAMINAR, U-shaped tendon that TWISTS through 180 degrees, so the CLAVICULAR fibres end up inserting LOWER and more anteriorly and the STERNOCOSTAL fibres HIGHER and more posteriorly • THE FUNCTION OF EACH PART, which is the question • CLAVICULAR HEAD — FLEXES the shoulder, bringing the arm FORWARDS AND UPWARDS from the anatomical position, and horizontally adducts. It works with anterior deltoid. TEST IT: push the arm forwards and upwards against resistance • STERNOCOSTAL HEAD — EXTENDS the FLEXED arm back down to the side against resistance, and adducts and medially rotates. It is the part used pushing down on the arms of a chair to stand up, or in a lat pull-down. TEST IT: hands on hips, press inwards — the anterior axillary fold stands out • SO THE TWO HEADS ARE ANTAGONISTS IN THE SAGITTAL PLANE, one flexing and one extending, while acting TOGETHER in ADDUCTION and MEDIAL ROTATION. That is the point of the question • Note POLAND SYNDROME — congenital absence of the sternocostal head, often with ipsilateral hand anomalies.
What is the nerve supply and root value of pectoralis major?TWO nerves, one for each part, and they are named after the CORD they come from, not the part they supply • LATERAL PECTORAL NERVE — from the LATERAL CORD of the brachial plexus, root value C5, C6, C7. It supplies chiefly the CLAVICULAR head • MEDIAL PECTORAL NERVE — from the MEDIAL CORD, root value C8, T1. It supplies the STERNOCOSTAL and abdominal parts, and it also supplies PECTORALIS MINOR, which it PIERCES on its way through • So the overall root value of pectoralis major is C5 to T1 — the whole plexus • THE TRAP: the LATERAL pectoral nerve supplies the muscle DIRECTLY, while the MEDIAL pectoral nerve reaches it only after passing THROUGH pectoralis minor. The two are joined in front of the axillary artery by a communicating loop, the ANSA PECTORALIS • CLINICAL RELEVANCE • in a MODIFIED RADICAL MASTECTOMY (Patey), pectoralis major is preserved and the pectoral nerves must be protected during axillary clearance, or the muscle wastes and the cosmetic and functional result is poor • the medial pectoral nerve is particularly vulnerable at level II of the axilla, behind pectoralis minor • the nerve is also used as a donor in nerve transfer surgery for brachial plexus injury.
What is the additional function of pectoralis major?It is an ACCESSORY MUSCLE OF RESPIRATION • THE MECHANISM, which is what the examiner wants: when the UPPER LIMB IS FIXED — the patient sitting forward with the hands braced on the knees or on a table, the TRIPOD POSITION — pectoralis major REVERSES ITS ORIGIN AND INSERTION. Instead of moving the humerus on the trunk, it pulls on the STERNUM AND RIBS from a fixed humerus, ELEVATING the chest wall and increasing the ANTEROPOSTERIOR DIAMETER of the thorax during FORCED INSPIRATION • That is exactly why a patient in acute severe ASTHMA or with COPD sits forward and braces their arms, and why you should recognise it as a sign of severe respiratory distress rather than just a posture • The other accessory muscles working the same way: PECTORALIS MINOR, SERRATUS ANTERIOR, STERNOCLEIDOMASTOID, the SCALENES and latissimus dorsi • A SECOND ADDITIONAL FUNCTION: with LATISSIMUS DORSI and TERES MAJOR it pulls the TRUNK UP TOWARDS A FIXED ARM — climbing a rope, pulling yourself out of a swimming pool, or bearing weight through crutches • AND A SURGICAL ONE worth adding: the PECTORALIS MAJOR MYOCUTANEOUS FLAP, pedicled on the thoracoacromial artery, is a workhorse reconstruction after head and neck cancer resection • It also forms the ANTERIOR AXILLARY FOLD, the landmark for the anterior wall of the axilla.
Identify the deltoid muscle. What is its function?DELTOID — the thick triangular muscle capping the shoulder and giving it its rounded contour • ORIGIN, and notice it MIRRORS THE INSERTION OF TRAPEZIUS exactly, point for point: the LATERAL THIRD OF THE CLAVICLE, the ACROMION, and the CREST OF THE SPINE OF THE SCAPULA • INSERTION: the DELTOID TUBEROSITY on the lateral surface of the shaft of the humerus, about halfway down • NERVE: the AXILLARY NERVE (C5, C6), from the POSTERIOR CORD • FUNCTION, by part — this is what earns the mark • ANTERIOR (clavicular) fibres — FLEXION and MEDIAL ROTATION • MIDDLE (acromial) fibres — ABDUCTION from about 15 degrees to 90 and beyond. These fibres are MULTIPENNATE, which buys POWER at the cost of range, and they are the strongest part • POSTERIOR (spinous) fibres — EXTENSION and LATERAL ROTATION • ACTING AS A WHOLE it is the CHIEF ABDUCTOR of the shoulder • THE CRUCIAL POINT: acting alone, deltoid's line of pull would drag the humeral head UPWARDS against the acromion rather than rotate it. It depends on the ROTATOR CUFF — chiefly supraspinatus and the inferior cuff — to DEPRESS AND CENTRE the head in the glenoid. That is the DELTOID-CUFF FORCE COUPLE, and it is why abduction is weak, painful and initiated by a shoulder shrug in a large cuff tear, and why the head migrates upwards on the radiograph • TESTING IT: abduct the arm to 90 degrees and resist, palpating the muscle belly; then test SENSATION over the REGIMENTAL BADGE AREA, the small patch over the lower deltoid supplied by the upper lateral cutaneous nerve of the arm • CLINICAL: the axillary nerve is injured in ANTERIOR SHOULDER DISLOCATION and SURGICAL NECK FRACTURE, and by badly placed intramuscular injections or by leaning on crutches. It runs through the QUADRANGULAR SPACE with the posterior circumflex humeral artery.
Which muscles flex the elbow?THREE main ones, and each is most efficient in a different position of the forearm — say that and the answer sounds like understanding rather than a list • BRACHIALIS — the WORKHORSE and the only PURE elbow flexor. Origin: the lower half of the front of the humerus. Insertion: the ULNAR TUBEROSITY and the coronoid process. Because it inserts on the ULNA, which does not rotate, it flexes the elbow WHATEVER the position of the forearm. NERVE: MUSCULOCUTANEOUS (C5, C6), with a small lateral slip from the RADIAL nerve (C7) — a genuine DUAL supply worth mentioning • BICEPS BRACHII — two heads: LONG head from the supraglenoid tubercle, running through the joint and down the intertubercular groove; SHORT head from the coracoid process. Insertion: the RADIAL TUBEROSITY, with the BICIPITAL APONEUROSIS to the deep fascia of the forearm. NERVE: MUSCULOCUTANEOUS (C5, C6). It flexes the elbow AND is the most POWERFUL SUPINATOR, especially with the elbow flexed to 90 — which is why a right-handed screw turns clockwise • BRACHIORADIALIS — from the lateral supracondylar ridge to the styloid process of the radius. NERVE: the RADIAL NERVE (C5, C6). It is the ONE MUSCLE SUPPLIED BY THE RADIAL NERVE THAT FLEXES THE ELBOW — the classic exception, since the radial nerve is otherwise the extensor nerve. It is most effective in the MID-PRONATED, thumb-up "hammer" position • ASSISTED weakly by PRONATOR TERES (median, C6, C7) and the common flexor origin • ROOT VALUE overall: C5, C6 • REFLEXES: the BICEPS JERK and the SUPINATOR (brachioradialis) JERK both test C5/C6; the TRICEPS JERK tests C7.
Identify the following on this image: the humeral head, the glenoid, the acromion, supraspinatus and the deltoid muscle.Orient yourself first — this is a CORONAL view through the shoulder, so you are looking at it from the front with the arm at the side • HUMERAL HEAD — the large ROUND articular surface medially and superiorly at the top of the humerus, capped by a thin layer of hyaline cartilage. Roughly a third of a sphere • GLENOID — the shallow, pear-shaped fossa of the SCAPULA that it articulates with, MEDIAL to the head. Look for the GLENOID LABRUM at its upper and lower margins: a small, dark, TRIANGULAR rim of fibrocartilage deepening the socket • ACROMION — the flat bony shelf ABOVE the humeral head, projecting laterally as the continuation of the scapular spine. It forms the ROOF • SUPRASPINATUS — the muscle sitting in the SUPRASPINOUS FOSSA above the scapular spine, its TENDON running LATERALLY in the narrow space BETWEEN the acromion above and the humeral head below, to reach the superior facet of the greater tubercle. Between the tendon and the acromion lies the SUBACROMIAL-SUBDELTOID BURSA, a thin bright line • DELTOID — the thick muscle capping the whole joint laterally, superficial to everything else, running from the acromion down onto the shaft • THE SPACE TO COMMENT ON: the gap between the top of the humeral head and the undersurface of the acromion is the SUBACROMIAL SPACE, normally 7-14 mm. It contains the supraspinatus tendon and the bursa, and NARROWING to less than about 7 mm, with the head riding up towards the acromion, indicates a large chronic ROTATOR CUFF TEAR • Look also for fluid in the bursa (subacromial bursitis), a hooked type III acromion, and discontinuity or high signal within the supraspinatus tendon in its CRITICAL ZONE about 1 cm from the insertion.
Identify the external oblique muscle of the abdomen on this prosection.EXTERNAL OBLIQUE is the MOST SUPERFICIAL of the three flat muscles of the abdominal wall • HOW TO RECOGNISE IT: its FIBRES RUN DOWNWARDS AND FORWARDS (inferomedially) — the direction your hands take when you put them into your front trouser pockets. That single cue distinguishes it from internal oblique, whose fibres run at RIGHT ANGLES to it • It is FLESHY laterally and becomes APONEUROTIC medially, roughly along a line dropped from the 9th costal cartilage to the ASIS. The aponeurosis passes in front of rectus abdominis to reach the LINEA ALBA, decussating with its fellow • WHAT ITS LOWER BORDER FORMS — worth pointing out unasked • the free lower border, rolled backwards on itself between the ASIS and the PUBIC TUBERCLE, is the INGUINAL LIGAMENT • a triangular gap in the aponeurosis just ABOVE and LATERAL to the pubic tubercle is the SUPERFICIAL INGUINAL RING • its continuation over the cord is the EXTERNAL SPERMATIC FASCIA • its most medial fibres turn back onto the pecten pubis as the LACUNAR LIGAMENT, the sharp medial border of the femoral ring • Identify also, on the same specimen: the LINEA ALBA in the midline, the LINEA SEMILUNARIS at the lateral border of rectus, and the TENDINOUS INTERSECTIONS crossing rectus abdominis.
Where does the external oblique originate, and what is its nerve supply?ORIGIN: from the OUTER SURFACES of the LOWER EIGHT RIBS — ribs 5 to 12 — by fleshy digitations. The upper five INTERDIGITATE with SERRATUS ANTERIOR and the lower three with LATISSIMUS DORSI. This interdigitation is visible on a lean subject and is worth pointing out • INSERTION: the fibres run downwards and forwards to reach • the anterior half of the OUTER LIP OF THE ILIAC CREST, by its posterior fleshy fibres • the PUBIC CREST and PUBIC TUBERCLE • the LINEA ALBA, through its broad aponeurosis • NERVE SUPPLY: the ANTERIOR RAMI of the LOWER SIX THORACIC NERVES — T7 to T11 as the lower intercostal nerves, and T12 as the SUBCOSTAL nerve • SET IT IN CONTEXT, which is what the examiner will want next • ALL THREE flat muscles and RECTUS ABDOMINIS share the segmental supply T7 to T12 • INTERNAL OBLIQUE and TRANSVERSUS ABDOMINIS receive an ADDITIONAL supply from L1, through the ILIOHYPOGASTRIC and ILIOINGUINAL nerves. External oblique does NOT — that is the difference, and it is why the L1 nerves matter for the conjoint tendon and not for external oblique • ACTIONS: acting with the other flat muscles it compresses the abdomen and raises intra-abdominal pressure; acting alone it FLEXES and rotates the trunk to the OPPOSITE side — so the right external oblique turns the trunk to the left, working with the LEFT internal oblique.
Identify the internal oblique on this prosection.INTERNAL OBLIQUE is the MIDDLE of the three flat muscles, deep to external oblique • THE RECOGNITION POINT: its fibres run UPWARDS AND FORWARDS (superomedially) — at RIGHT ANGLES to external oblique. Put one hand flat on your chest pointing up and in, and the other in your pocket pointing down and in, and you have the two directions • ORIGIN: the THORACOLUMBAR FASCIA posteriorly, the anterior TWO-THIRDS of the INTERMEDIATE LINE of the iliac crest, and the LATERAL TWO-THIRDS of the INGUINAL LIGAMENT • INSERTION: the lower three or four COSTAL CARTILAGES, the LINEA ALBA through its aponeurosis, and the PUBIC CREST and PECTINEAL LINE through the CONJOINT TENDON • NERVE: T7 to T12 PLUS L1 (iliohypogastric and ilioinguinal) • THREE FEATURES WORTH VOLUNTEERING • its aponeurosis SPLITS at the lateral border of rectus to pass BOTH in front of and behind the muscle, forming both walls of the rectus sheath — but only ABOVE the ARCUATE LINE. Below that line it passes entirely IN FRONT • its lowest fibres arch over the spermatic cord and become the CONJOINT TENDON with transversus • it contributes the CREMASTER MUSCLE and the cremasteric fascia to the spermatic cord • The layers in order from the surface, which you should be able to recite: skin, Camper's fatty fascia, Scarpa's membranous fascia, EXTERNAL OBLIQUE, INTERNAL OBLIQUE, TRANSVERSUS ABDOMINIS, transversalis fascia, extraperitoneal fat, parietal peritoneum.
Which abdominal muscle has fleshy fibres that lie anterior to the deep inguinal ring?INTERNAL OBLIQUE • THE ANATOMY: the DEEP (internal) INGUINAL RING is not a ring in a muscle at all — it is an opening in the TRANSVERSALIS FASCIA, lying about 1.25 cm ABOVE the MIDPOINT OF THE INGUINAL LIGAMENT, and just LATERAL to the INFERIOR EPIGASTRIC VESSELS • Do not confuse the MIDPOINT of the inguinal ligament (ASIS to pubic tubercle, the deep ring) with the MID-INGUINAL POINT (ASIS to pubic symphysis, the femoral artery). That distinction is examined constantly • The FLESHY FIBRES OF INTERNAL OBLIQUE, arising from the lateral two-thirds of the inguinal ligament, ARCH UPWARDS AND OVER the deep ring, lying IN FRONT of it and above it, before descending to the conjoint tendon. TRANSVERSUS ABDOMINIS arises more medially, from the lateral third only, so it does NOT lie in front of the ring • WHY IT MATTERS — THE SHUTTER MECHANISM: when intra-abdominal pressure rises with coughing or straining, internal oblique and transversus CONTRACT and their arched fibres FLATTEN DOWN towards the inguinal ligament, closing the canal like a shutter and pressing the posterior wall forwards against the anterior wall • Together with the OBLIQUITY of the canal — the deep and superficial rings do not lie opposite each other — and the FLAP-VALVE action, this is why an inguinal hernia is not universal despite the canal being an inherent weakness • Denervating those fibres, for example by injuring the iliohypogastric nerve at appendicectomy, abolishes the shutter and predisposes to a DIRECT hernia.
Identify the appendix, the caecum, the terminal ileum and the ascending colon on this prosection.CAECUM — the blind, sac-like commencement of the large bowel in the RIGHT ILIAC FOSSA, below the level of the ileocaecal junction. It is usually covered on all sides by peritoneum but has NO mesentery of its own • TERMINAL ILEUM — enters the large bowel from the MEDIAL side at the ILEOCAECAL VALVE, at the junction of caecum and ascending colon. It is small-calibre, smooth-walled, with a mesentery • ASCENDING COLON — runs UPWARDS from the caecum in the right paracolic gutter to the HEPATIC FLEXURE. It is SECONDARILY RETROPERITONEAL, covered by peritoneum only on its front and sides. Recognise large bowel by its three features: TAENIAE COLI, HAUSTRA and APPENDICES EPIPLOICAE • APPENDIX — a blind muscular tube arising from the POSTEROMEDIAL wall of the caecum about 2 cm BELOW the ileocaecal valve. It has its own short mesentery, the MESOAPPENDIX, in the free edge of which runs the APPENDICULAR ARTERY • THE TRICK FOR FINDING THE APPENDIX AT OPERATION, and say it: the THREE TAENIAE COLI of the caecum CONVERGE ON THE BASE OF THE APPENDIX. Follow any one of them — usually the anterior taenia, the taenia libera — down to the base. The BASE is CONSTANT; only the TIP wanders • SURFACE MARKING of the base: McBURNEY'S POINT, one third of the way along a line from the RIGHT ASIS to the UMBILICUS • The appendix is a MIDGUT structure, and it is lined with abundant lymphoid tissue, most prominent in the second decade — which is when appendicitis peaks.
Identify the following structures on this prosection: the round ligament, the ligament of the ovary, the ovary and the uterine tube.OVARY — the almond-shaped, slightly puckered organ on the LATERAL PELVIC WALL, sitting in the OVARIAN FOSSA, which is bounded by the EXTERNAL ILIAC VESSELS above and the URETER and INTERNAL ILIAC VESSELS behind. It is attached to the BACK of the broad ligament by the MESOVARIUM. Note it is NOT covered by peritoneum — it has a germinal epithelium — which is why ovarian carcinoma seeds transcoelomically so readily • LIGAMENT OF THE OVARY (the ovarian ligament proper) — a short fibrous cord running MEDIALLY from the UTERINE POLE of the ovary to the uterus, entering it just BELOW AND BEHIND the uterotubal junction • ROUND LIGAMENT OF THE UTERUS — leaves the uterus at the SAME POINT but just BELOW AND IN FRONT of the tube, and runs FORWARDS AND LATERALLY in the broad ligament to the DEEP INGUINAL RING, through the inguinal canal, to end in the LABIUM MAJUS • THE UNIFYING FACT, which is the answer the examiner is waiting for: BOTH are remnants of the SAME structure, the GUBERNACULUM. The ovarian ligament is the part ABOVE its attachment to the uterus, the round ligament the part BELOW • UTERINE (FALLOPIAN) TUBE — lies in the FREE UPPER BORDER of the broad ligament, in the MESOSALPINX. FOUR PARTS, from lateral to medial: INFUNDIBULUM with its FIMBRIAE, AMPULLA (the widest and longest — the normal site of FERTILISATION and the commonest site of ECTOPIC pregnancy), ISTHMUS (the narrowest, and the site chosen for tubal ligation) and the INTRAMURAL part • ALSO IDENTIFY the SUSPENSORY LIGAMENT OF THE OVARY (the infundibulopelvic ligament), a fold of peritoneum carrying the OVARIAN VESSELS down from the posterior abdominal wall. It is ligated in oophorectomy, and the URETER runs immediately beneath it — the classic site of ureteric injury.
Point to the recess between the rectum and the uterus. What is this recess called? Identify the ovaries.It is the RECTOUTERINE POUCH, universally known as the POUCH OF DOUGLAS • BOUNDARIES: the RECTUM behind; the POSTERIOR WALL OF THE UTERUS and the POSTERIOR FORNIX OF THE VAGINA in front; laterally the rectouterine folds, raised by the uterosacral ligaments • ITS SIGNIFICANCE: it is the MOST DEPENDENT (lowest) part of the PERITONEAL CAVITY in the FEMALE in the erect or semi-recumbent position. Anything free in the peritoneum — blood, pus, ascites, malignant deposits — gravitates here • CLINICAL CONSEQUENCES • a ruptured ECTOPIC PREGNANCY fills it with blood, giving cervical excitation and a boggy, exquisitely tender mass on vaginal examination • a PELVIC ABSCESS collects here after perforated appendicitis or diverticulitis, giving swinging fever, diarrhoea and a tender mass felt on rectal examination. It can be drained through the posterior vaginal fornix • transcoelomic spread of gastric or ovarian carcinoma deposits here as a BLUMER'S SHELF, palpable on PR, and a KRUKENBERG tumour in the ovaries • CULDOCENTESIS is needle aspiration through the posterior fornix into this pouch • IN THE MALE the equivalent and equally dependent recess is the RECTOVESICAL POUCH • The ANTERIOR recess, between the bladder and the uterus, is the shallower VESICOUTERINE POUCH — it does not reach the vagina, because the peritoneum reflects at the level of the isthmus, which is why the bladder can be reflected down at a lower segment Caesarean section • THE OVARIES are NOT in the pouch: they lie on the LATERAL pelvic wall in the OVARIAN FOSSAE, attached to the back of the broad ligament, though a prolapsed or enlarged ovary may be palpable through the posterior fornix.
Which dermatome lies at the level of the umbilicus, and which dermatomes lie in the anterior abdominal wall above it?The UMBILICUS is T10 • THE LANDMARKS TO KNOW, and give them as a ladder • T4 — the NIPPLE • T6 to T7 — the XIPHISTERNUM • T8 — midway between the xiphisternum and the umbilicus • T10 — the UMBILICUS • T12 — just above the pubic symphysis • L1 — the GROIN and the inguinal region • So ABOVE the umbilicus, the anterior abdominal wall is supplied by T7, T8 and T9, with T6 reaching the epigastrium at the xiphisternum. BELOW it, by T11, T12 and L1 • THE NERVES THEMSELVES: the anterior rami of T7 to T11 continue from the intercostal spaces into the abdominal wall as the lower INTERCOSTAL nerves; T12 is the SUBCOSTAL nerve; L1 supplies the wall through the ILIOHYPOGASTRIC and ILIOINGUINAL nerves • WHY THESE MATTER CLINICALLY • they anchor the REFERRED PAIN of the abdominal viscera — foregut to T6-T9 (epigastrium), midgut to T10 (umbilicus), hindgut to T11-L1 (suprapubic) • a shingles rash in a band across the abdomen identifies the segment exactly • checking the sensory level after spinal anaesthesia: T10 for a Caesarean section is NOT enough because peritoneal traction is felt higher — a block to T4 is aimed for • loss of the abdominal reflexes: upper T8-T9, lower T10-T12.
In acute appendicitis, why is the pain first referred to the umbilical region?Because early appendicitis produces VISCERAL pain, and the appendix is a MIDGUT structure whose visceral afferents enter the cord at T10 — the segment whose dermatome is the UMBILICUS • THE MECHANISM, step by step • obstruction of the lumen — by a faecolith, lymphoid hyperplasia, a tumour or a parasite — causes continued mucus secretion, DISTENSION and rising intraluminal pressure • distension and stretch of smooth muscle stimulate VISCERAL AFFERENT fibres, which run WITH THE SYMPATHETIC NERVES, back through the superior mesenteric plexus and the LESSER and LEAST SPLANCHNIC nerves to the T10 spinal segment • in the dorsal horn these afferents converge on the same second-order neurones as the somatic afferents from the T10 DERMATOME. The brain has no way of distinguishing them and attributes the pain to the skin — the classic CONVERGENCE theory of referred pain • THE CHARACTER follows from that: visceral pain is DULL, VAGUE, POORLY LOCALISED, MIDLINE, often colicky, and associated with nausea, vomiting and anorexia. The patient cannot point to it with one finger • THE GENERAL RULE TO STATE: FOREGUT refers to the EPIGASTRIUM, MIDGUT to the UMBILICUS, HINDGUT to the SUPRAPUBIC region. It follows the arterial supply — coeliac, superior mesenteric, inferior mesenteric — because the afferents travel back alongside the vessels • It is MIDLINE because the viscera are supplied BILATERALLY, so the pain cannot be lateralised.
When the pain moves to the right iliac fossa, what structure has become involved in the inflammatory process?The PARIETAL PERITONEUM of the right iliac fossa — and, with it, the adjacent abdominal wall • WHY THE CHARACTER OF THE PAIN CHANGES COMPLETELY: parietal peritoneum is NOT visceral. It is supplied by the SOMATIC segmental nerves of the overlying body wall — here T12 (subcostal) and L1 (iliohypogastric and ilioinguinal). Somatic pain is SHARP, SEVERE, CONSTANT and PRECISELY LOCALISED to the site of irritation, because the somatic system has a fine, unilateral, point-to-point representation • So the SHIFT OF PAIN marks the moment inflammation extends through the FULL THICKNESS of the appendix wall and its serosa to irritate the parietal peritoneum lying against it. The patient can now point to the spot with ONE FINGER • THAT IS ALSO WHEN THE SIGNS APPEAR: localised tenderness at McBURNEY'S POINT, GUARDING, PERCUSSION and REBOUND tenderness, pain on coughing, and reluctance to move — all of them signs of PARIETAL peritoneal irritation • THE SHIFT IS THE MOST DISCRIMINATING SINGLE FEATURE in the history, more useful than any single sign • AND THE COROLLARY, worth adding: if the appendix is RETROCAECAL, it lies away from the anterior parietal peritoneum, so the classic shift may NEVER HAPPEN. Instead the inflamed appendix irritates the PSOAS FASCIA, and you get a positive psoas sign with vague, poorly localised pain — which is exactly why retrocaecal appendicitis is the one that gets missed.
Name three positions in which the appendix may lie.The BASE is CONSTANT — the taeniae coli always converge on it, 2 cm below the ileocaecal valve. Only the TIP varies • RETROCAECAL or RETROCOLIC — much the commonest, about 65-75%. The tip runs upwards behind the caecum, on the psoas fascia and iliacus. Tenderness is higher and more lateral, guarding may be absent because the anterior parietal peritoneum is spared, and there is a POSITIVE PSOAS SIGN • PELVIC or DESCENDING — about 20-30%. The tip hangs over the pelvic brim, against the bladder and rectum, giving DIARRHOEA and URINARY FREQUENCY, tenderness on rectal examination, and often minimal abdominal signs. In the female it lies against the right adnexa, which is why the differential includes salpingitis, ectopic pregnancy and a ruptured ovarian cyst • SUBCAECAL, PRE-ILEAL and POST-ILEAL — the remainder. POST-ILEAL is the most difficult of all, because the inflamed appendix is shielded by loops of small bowel; the presentation is late, with vomiting and diarrhoea and few localising signs • THE RARE ONES, if pressed: SUBHEPATIC in malrotation, and LEFT-SIDED in situs inversus or a very long mobile caecum • THE CLINICAL PRINCIPLE: the variable position of the tip explains why the presentation of appendicitis is so variable and why it remains the commonest cause of a negative laparotomy. It also justifies imaging in the young female, in whom the differential is widest.
Why does extension of the right hip exacerbate the pain of acute appendicitis?This is the PSOAS SIGN, and it indicates a RETROCAECAL appendix • THE MECHANISM: a retrocaecal appendix lies directly on PSOAS MAJOR, separated from it only by the psoas fascia. When it becomes inflamed, the surrounding fascia and muscle become irritated • PSOAS MAJOR IS A FLEXOR OF THE HIP. EXTENDING the hip therefore STRETCHES it, moving the muscle beneath the inflamed appendix and reproducing the pain • HOW TO PERFORM IT: lay the patient on their LEFT side, then passively EXTEND the RIGHT hip with the knee straight. Pain in the right iliac fossa is a positive sign. Alternatively ask the supine patient to flex the right hip against your resistance • THE COROLLARY YOU CAN OBSERVE BEFORE YOU TOUCH THE PATIENT: they lie still with the RIGHT HIP FLEXED, because that position RELAXES psoas. A patient walking in with a slight limp and a flexed right hip has told you something already • TWO RELATED SIGNS TO OFFER • the OBTURATOR SIGN — pain on passive INTERNAL ROTATION of the FLEXED right hip, indicating a PELVIC appendix lying on obturator internus • ROVSING'S SIGN — palpation in the LEFT iliac fossa produces pain in the RIGHT, from displacement of gas and peritoneal stretch • Remember psoas major also carries the LUMBAR PLEXUS within and behind it, and a psoas abscess produces exactly the same posture — which is why a psoas abscess and a retrocaecal appendix can look identical on examination.
Name the embryological remnant that should also be included in the differential diagnosis of appendicitis.MECKEL'S DIVERTICULUM — the persistent proximal portion of the VITELLO-INTESTINAL (omphalomesenteric) DUCT • It is a TRUE diverticulum: it contains ALL THREE layers of the bowel wall, and it has its own blood supply from a remnant of the vitelline artery • THE RULE OF TWOS, and give it as a list • present in about 2% of the population • about 2 INCHES long • within 2 FEET of the ILEOCAECAL VALVE • on the ANTIMESENTERIC border of the ILEUM • may contain 2 types of ECTOPIC TISSUE — GASTRIC and PANCREATIC • usually presents before the age of 2 • about twice as common in MALES • PRESENTATIONS • PAINLESS RECTAL BLEEDING, the commonest in children, from peptic ulceration of adjacent ileal mucosa by acid from the ectopic GASTRIC tissue • DIVERTICULITIS, which is CLINICALLY INDISTINGUISHABLE from acute appendicitis — hence this question • INTESTINAL OBSTRUCTION from intussusception, volvulus round a persistent fibrous band to the umbilicus, or a Littre's hernia • PERFORATION • DIAGNOSIS: a technetium-99m PERTECHNETATE scan, the MECKEL'S SCAN, which is taken up by ectopic gastric mucosa • THE OPERATIVE RULE, and this is the practical point: at appendicectomy, IF THE APPENDIX LOOKS NORMAL, you must run the TERMINAL ILEUM for at least 2 FEET to look for a Meckel's diverticulum — and also examine the pelvic organs in a female and the mesenteric nodes for mesenteric adenitis.
At open appendicectomy the external oblique aponeurosis is exposed. In which direction do its fibres run?DOWNWARDS AND MEDIALLY — inferomedially, from upper-lateral to lower-medial. The everyday cue is the direction of putting your HANDS INTO YOUR FRONT TROUSER POCKETS • WHY THE QUESTION IS ASKED: the classic appendicectomy incision is the GRIDIRON (McBURNEY) incision, and the whole technique depends on fibre direction • the SKIN incision is made at RIGHT ANGLES to the spino-umbilical line, centred on McBurney's point — one third of the way from the right ASIS to the umbilicus • the EXTERNAL OBLIQUE APONEUROSIS is then SPLIT ALONG the line of its fibres, INFEROMEDIALLY • INTERNAL OBLIQUE and TRANSVERSUS ABDOMINIS beneath it run SUPEROMEDIALLY — at RIGHT ANGLES — and are split along THEIR fibres, bluntly, with a pair of artery forceps and two retractors • That crisscross of split layers, like the iron bars of a grid, is what gives the GRIDIRON its name • WHY SPLIT RATHER THAN CUT: muscle fibres are separated, not divided. The segmental nerve supply running in the neurovascular plane is preserved, the layers close over one another in different directions when released, and the wound is strong with a very low incisional hernia rate • THE LANZ INCISION is the same approach through a TRANSVERSE skin crease incision, giving a better cosmetic scar because it follows Langer's lines • IF ACCESS IS INADEQUATE, the incision can be extended medially by dividing the anterior rectus sheath and retracting rectus (a Rutherford Morison extension).
Which muscles combine to form the conjoint tendon?The CONJOINT TENDON (falx inguinalis) is formed by the fusion of the aponeuroses of the INTERNAL OBLIQUE and the TRANSVERSUS ABDOMINIS — their LOWEST fibres, which arise from the lateral part of the inguinal ligament • COURSE AND INSERTION: those fibres ARCH upwards and over the spermatic cord, then turn downwards behind it to insert into the PUBIC CREST and the PECTINEAL LINE (pecten pubis) of the superior pubic ramus • WHERE IT LIES AND WHY THAT MATTERS: it forms the MEDIAL part of the POSTERIOR WALL of the inguinal canal, sitting DIRECTLY BEHIND the SUPERFICIAL INGUINAL RING. So it reinforces the wall at precisely the point where the canal is otherwise weakest • THE WALLS OF THE CANAL, for completeness • ANTERIOR: external oblique aponeurosis throughout, reinforced laterally by internal oblique • POSTERIOR: transversalis fascia throughout, reinforced medially by the CONJOINT TENDON • ROOF: the arching fibres of internal oblique and transversus • FLOOR: the in-rolled inguinal ligament, and the lacunar ligament medially • CLINICAL: a WEAK or DEFICIENT conjoint tendon leaves HESSELBACH'S TRIANGLE unsupported and predisposes to a DIRECT inguinal hernia, which pushes forwards MEDIAL to the inferior epigastric vessels. Hesselbach's triangle is bounded by the inferior epigastric vessels laterally, the lateral border of rectus medially and the inguinal ligament below • It is also the structure sutured to the inguinal ligament in the old Bassini and Shouldice repairs, before mesh made tension-free repair standard.
The nerve supplying the muscle fibres that go on to form the conjoint tendon may be injured during appendicectomy. Which nerve, and what is its root value?The ILIOHYPOGASTRIC NERVE, root value L1 — and the ILIOINGUINAL NERVE, also L1, is at risk alongside it. Both are branches of the LUMBAR PLEXUS. The iliohypogastric often carries a small contribution from T12 • WHY THEY ARE VULNERABLE: after emerging from the lateral border of psoas and crossing quadratus lumborum, both nerves PIERCE TRANSVERSUS ABDOMINIS and run FORWARDS IN THE NEUROVASCULAR PLANE BETWEEN INTERNAL OBLIQUE AND TRANSVERSUS — exactly the plane a gridiron incision splits. The iliohypogastric then pierces internal oblique about 2 cm above the ASIS • THEY ARE INJURED BY: a gridiron or Lanz incision placed TOO LOW or TOO MEDIALLY, vigorous retraction, a deep suture placed blindly when closing internal oblique, or a stitch taken during hernia repair • THE CONSEQUENCE — and this is why the question is worth asking: these nerves supply the LOWEST FIBRES OF INTERNAL OBLIQUE AND TRANSVERSUS, the very fibres that arch over the cord and form the CONJOINT TENDON. Denervating them PARALYSES THE SHUTTER MECHANISM and weakens the posterior wall of the inguinal canal, so the patient may develop a DIRECT INGUINAL HERNIA on that side months or years later. A right-sided direct hernia in a patient with a McBurney scar is the classic story • The sensory loss is over the suprapubic skin (iliohypogastric) and the upper medial thigh and anterior scrotum or labium (ilioinguinal), and entrapment in scar tissue causes a chronic neuralgia • They are the target of the ilioinguinal-iliohypogastric block, and of the TAP block placed in that same plane.
Which branch of the superior mesenteric artery usually gives off the appendicular and caecal arteries?The ILEOCOLIC ARTERY — the LOWEST and LAST branch to arise from the RIGHT side of the superior mesenteric artery • ITS BRANCHES • the ANTERIOR and POSTERIOR CAECAL arteries • the APPENDICULAR ARTERY • an ASCENDING (colic) branch, which anastomoses with the descending branch of the right colic • an ILEAL branch, which anastomoses with the last ileal branch of the SMA • THE APPENDICULAR ARTERY is the one to describe in detail: it arises from the ileocolic (or from its ileal branch), passes BEHIND THE TERMINAL ILEUM, and then runs in the FREE EDGE OF THE MESOAPPENDIX to reach the tip • IT IS AN END ARTERY. That single fact explains the natural history of appendicitis: once the artery thromboses in the inflamed mesoappendix, there is no collateral supply, so the appendix undergoes ISCHAEMIC NECROSIS and PERFORATES — typically within 24-72 hours, and sooner at the tip, which is the most distal part of the supply • SURGICAL RELEVANCE • at appendicectomy the mesoappendix is divided and the appendicular artery ligated or clipped first, then the base is crushed and ligated • the ILEOCOLIC ARTERY is the vessel taken at its origin in a RIGHT HEMICOLECTOMY, along with the right colic and the right branch of the middle colic • it is also the landmark for the start of a laparoscopic medial-to-lateral mobilisation of the right colon.
How do you mobilise the right colon, and why? What is the name of the plane you are trying to find?HOW: incise the peritoneum along the LATERAL peritoneal reflection in the right paracolic gutter — the WHITE LINE OF TOLDT, a visible pale line — starting at the caecum and working upwards towards the hepatic flexure. Then sweep the colon and its mesentery MEDIALLY, off the retroperitoneum, using gentle blunt dissection in the areolar plane that opens up in front of you • (Laparoscopically the same plane is usually entered the other way round, MEDIAL TO LATERAL, starting at the ileocolic pedicle) • WHY: the ascending colon is SECONDARILY RETROPERITONEAL. In development it had a mesentery; as the midgut rotated and the colon came to lie against the posterior wall, the two peritoneal layers FUSED. Mobilisation is simply UNDOING that embryological fusion • THE PLANE: the fusion plane is TOLDT'S FASCIA, and the avascular plane developed there is the MESOFASCIAL PLANE, entered along the WHITE LINE OF TOLDT • WHY IT IS THE RIGHT PLANE • it is AVASCULAR, so the dissection is bloodless • it keeps the MESOCOLON INTACT with its lymphatics and vessels, which is the principle of COMPLETE MESOCOLIC EXCISION and of oncological clearance — the exact analogue of the TOTAL MESORECTAL EXCISION plane in the rectum • it leaves the RETROPERITONEAL STRUCTURES BEHIND, safely down on the posterior wall: the URETER, the GONADAL VESSELS, the SECOND PART OF THE DUODENUM, the INFERIOR VENA CAVA and GEROTA'S (renal) FASCIA over the kidney • IF YOU STRAY TOO DEEP you lift Gerota's fascia and take the ureter, the gonadal vessels or the duodenum with the specimen. The rule is: SEE THE DUODENUM, SEE THE URETER, and stay in front of both.
The neurovascular bundle of the anterior abdominal wall usually lies between which layers?Between INTERNAL OBLIQUE and TRANSVERSUS ABDOMINIS — the NEUROVASCULAR PLANE of the abdominal wall • THIS IS THE SAME PLANE AS IN THE CHEST, and saying so shows you understand it rather than remember it: in the intercostal space the bundle lies between the INTERNAL INTERCOSTAL and the INNERMOST INTERCOSTAL muscles. Transversus abdominis is the abdominal continuation of the innermost layer, so the plane simply carries on • WHAT RUNS IN IT: the anterior rami of T7 to T11 (the lower intercostal nerves), T12 (subcostal), and L1 as the ILIOHYPOGASTRIC and ILIOINGUINAL nerves, together with the accompanying posterior intercostal, lumbar and deep circumflex iliac vessels • WHERE THEY GO NEXT: at the lateral border of rectus the nerves pierce the rectus sheath and enter RECTUS ABDOMINIS from its DEEP AND LATERAL aspect, then continue as anterior cutaneous branches through the anterior sheath • THREE CLINICAL CONSEQUENCES • the TAP BLOCK (transversus abdominis plane block) deposits local anaesthetic exactly here, classically at the TRIANGLE OF PETIT, and under ultrasound you look for the plane between the second and third muscle layers • a PARAMEDIAN or lateral vertical incision cuts these nerves as they enter rectus and DENERVATES the muscle medial to it, causing wasting and bulging. A MIDLINE incision through the LINEA ALBA divides no nerves at all, which is one reason it remains the standard emergency laparotomy incision • splitting muscles ALONG their fibres, as in a gridiron incision, preserves the plane and the nerves within it.
This is a prosection of rectus abdominis. Identify the structures and describe its function.IDENTIFY • RECTUS ABDOMINIS itself — a long strap muscle on either side of the midline, broader above and narrower below • its TENDINOUS INTERSECTIONS — usually three, at the xiphoid, the umbilicus and midway between. They are attached to the ANTERIOR wall of the sheath only, NOT the posterior — which is why the sheath cannot be stripped from the front but lifts easily from behind, and why the muscle shows as a "six-pack" • the LINEA ALBA in the midline, and the LINEA SEMILUNARIS at its lateral border • PYRAMIDALIS, a small triangular muscle in front of the lower rectus, tensing the linea alba, supplied by T12 • the ARCUATE LINE, midway between umbilicus and pubis • the INFERIOR EPIGASTRIC VESSELS entering the sheath at that level and running upwards behind the muscle • ATTACHMENTS: from the PUBIC CREST, PUBIC SYMPHYSIS and tubercle below, to the 5TH, 6TH and 7TH COSTAL CARTILAGES and the XIPHOID PROCESS above • NERVE: T7 to T12, entering from the LATERAL side • BLOOD SUPPLY: the SUPERIOR EPIGASTRIC (from the internal thoracic) above and the INFERIOR EPIGASTRIC (from the external iliac) below, anastomosing within the muscle — the basis of the TRAM and DIEP flaps, and an important collateral channel in aortic coarctation • THE SHEATH: ABOVE the arcuate line the internal oblique aponeurosis SPLITS to pass in front of and behind rectus, with external oblique in front and transversus behind. BELOW the arcuate line ALL THREE aponeuroses pass IN FRONT, so there is NO POSTERIOR SHEATH — only transversalis fascia • FUNCTIONS • FLEXES the trunk, approximating the ribs and the pubis — the sit-up • raises INTRA-ABDOMINAL PRESSURE with the flat muscles, for forced expiration, coughing, sneezing, vomiting, micturition, defecation and parturition • STABILISES the pelvis and supports the viscera • acts as an ANTAGONIST to erector spinae, maintaining posture and protecting the lumbar spine • CLINICAL: a RECTUS SHEATH HAEMATOMA from a torn inferior epigastric artery — Fothergill's sign, a mass that does not cross the midline and becomes MORE prominent on tensing the muscle; and DIVARICATION OF THE RECTI.
MRCS Part B · Mo’s Notes
Part B Drill
0secured
0weak
0untouched
Backup & restore progress
Your marks sync on their own. This code is the manual backup — copy it somewhere safe, or paste one in to restore.