Keyword Definitions
• Musculocutaneous nerve – Terminal branch of lateral cord of brachial plexus, supplies flexors of arm.
• Brachial plexus – Nerve network supplying upper limb.
• Flexor compartment of arm – Contains biceps brachii, brachialis, and coracobrachialis.
• Biceps brachii – Flexor of elbow, supinator of forearm.
• Coracobrachialis – Flexes and adducts the arm.
• Brachialis – Primary flexor of elbow.
• Radial nerve – Supplies extensor compartment of arm.
• Median nerve – Supplies forearm and hand, not arm flexors.
• Ulnar nerve – Supplies intrinsic hand muscles and part of forearm.
• Clinical test – Elbow flexion and cutaneous sensation of lateral forearm test musculocutaneous nerve.
• Upper limb injuries – Trauma, fractures, or entrapment may affect musculocutaneous nerve function.
Chapter: Anatomy / Upper Limb
Topic: Brachial Plexus
Subtopic: Musculocutaneous Nerve and Arm Flexors
Lead Question – 2013
Nerve supply to the muscles of flexor compartment of arm?
a) Radial nerve
b) Median nerve
c) Musculocutaneous nerve
d) Ulnar nerve
Explanation: The flexor compartment of the arm (biceps brachii, brachialis, coracobrachialis) is innervated by the musculocutaneous nerve, a branch of the lateral cord of the brachial plexus. Correct answer: (c) Musculocutaneous nerve. Clinical: Injury leads to weak elbow flexion and sensory loss over lateral forearm.
Guessed Questions for NEET PG
1) Which nerve continues as the lateral cutaneous nerve of forearm?
a) Radial
b) Median
c) Musculocutaneous
d) Ulnar
Explanation: Musculocutaneous nerve ends as lateral cutaneous nerve of forearm. Correct answer: Musculocutaneous nerve. Clinical: Injury causes sensory loss in lateral forearm.
2) Which muscle is pierced by musculocutaneous nerve?
a) Biceps brachii
b) Coracobrachialis
c) Brachialis
d) Deltoid
Explanation: Musculocutaneous nerve pierces coracobrachialis before supplying flexor compartment. Correct answer: Coracobrachialis. Clinical: Landmark for nerve tracing.
3) Which muscle in flexor compartment also receives supply from radial nerve?
a) Biceps brachii
b) Coracobrachialis
c) Brachialis
d) None
Explanation: Brachialis is mainly supplied by musculocutaneous nerve, but radial nerve gives additional innervation. Correct answer: Brachialis. Clinical: Explains preserved flexion in musculocutaneous injury.
4) Elbow flexion against resistance tests mainly?
a) Median nerve
b) Musculocutaneous nerve
c) Ulnar nerve
d) Axillary nerve
Explanation: Biceps brachii and brachialis, innervated by musculocutaneous nerve, are prime elbow flexors. Correct answer: Musculocutaneous nerve. Clinical: Used to check function.
5) Which branch of brachial plexus gives rise to musculocutaneous nerve?
a) Lateral cord
b) Posterior cord
c) Medial cord
d) Upper trunk
Explanation: Musculocutaneous nerve arises from the lateral cord (C5–C7 roots). Correct answer: Lateral cord. Clinical: Knowledge useful in brachial plexus blocks.
6) Sensory loss over lateral forearm is due to injury of?
a) Radial nerve
b) Musculocutaneous nerve
c) Median nerve
d) Ulnar nerve
Explanation: Lateral cutaneous nerve of forearm (continuation of musculocutaneous) supplies skin here. Correct answer: Musculocutaneous nerve. Clinical: Sensory deficit confirms diagnosis.
7) Which movement is most affected in musculocutaneous nerve injury?
a) Shoulder abduction
b) Elbow flexion
c) Wrist extension
d) Finger flexion
Explanation: Musculocutaneous injury impairs elbow flexion due to paralysis of biceps and brachialis. Correct answer: Elbow flexion. Clinical: Weak supination also observed.
8) A patient with injury to musculocutaneous nerve will show weakness of?
a) Forearm pronation
b) Elbow flexion
c) Finger extension
d) Thumb opposition
Explanation: Injury leads to loss of flexors of arm, causing weak elbow flexion. Correct answer: Elbow flexion. Clinical: Supination also affected due to biceps involvement.
9) Which muscle is absent in flexor compartment if musculocutaneous nerve is injured?
a) Deltoid
b) Coracobrachialis
c) Triceps
d) Supinator
Explanation: Coracobrachialis is supplied by musculocutaneous nerve and loses function in its injury. Correct answer: Coracobrachialis. Clinical: Shoulder adduction and flexion weakened.
10) Which of the following is NOT supplied by musculocutaneous nerve?
a) Biceps brachii
b) Brachialis
c) Coracobrachialis
d) Triceps brachii
Explanation: Triceps brachii belongs to extensor compartment, supplied by radial nerve. Correct answer: Triceps brachii. Clinical: Preserved triceps function rules out musculocutaneous injury.
Keyword Definitions
• Supination – Outward rotation of forearm turning palm upward.
• Pronation – Inward rotation of forearm turning palm downward.
• Biceps brachii – Flexor of elbow and chief supinator when forearm flexed.
• Supinator muscle – Assists in supination, especially when elbow extended.
• Brachioradialis – Flexes elbow, acts in mid-prone position, not supination.
• FDS (Flexor digitorum superficialis) – Flexes middle phalanges, unrelated to supination.
• Anconeus – Assists in elbow extension, stabilizes joint, not in supination.
• Musculocutaneous nerve – Innervates biceps brachii.
• Radial nerve – Innervates supinator and brachioradialis.
• Clinical test – Turning a screwdriver tests supination and biceps activity.
• Spiral groove – Radial nerve and profunda brachii pass here, relevant for supinator function.
Chapter: Anatomy / Upper Limb
Topic: Muscles of Forearm and Arm
Subtopic: Supinators of Forearm
Lead Question – 2013
Muscle causing supination of forearm?
a) Biceps brachii
b) Brachioradialis
c) FDS
d) Anconeus
Explanation: Supination is mainly caused by biceps brachii when the elbow is flexed and by supinator when the elbow is extended. Other listed muscles are not supinators. Correct answer: (a) Biceps brachii. Clinical: Weak supination occurs in musculocutaneous nerve or radial nerve injury.
Guessed Questions for NEET PG
1) Supination in extended elbow is mainly by?
a) Supinator
b) Biceps brachii
c) Pronator teres
d) Anconeus
Explanation: Supinator acts strongly when elbow is extended, while biceps dominates in flexion. Correct answer: Supinator. Clinical: Radial nerve injury weakens supination.
2) Which nerve supplies the supinator muscle?
a) Median
b) Radial (deep branch)
c) Musculocutaneous
d) Ulnar
Explanation: Supinator is supplied by deep branch of radial nerve. Correct answer: Radial nerve (deep branch). Clinical: Compression in supinator leads to posterior interosseous nerve syndrome.
3) Turning a screwdriver involves mainly?
a) Pronator quadratus
b) Biceps brachii
c) Anconeus
d) Flexor carpi radialis
Explanation: Biceps brachii provides strong supination, especially in flexed forearm. Correct answer: Biceps brachii. Clinical: Fatigue in this muscle seen in repetitive screw turning.
4) A patient with musculocutaneous nerve injury will have weakness in?
a) Supination with flexed elbow
b) Supination with extended elbow
c) Pronation
d) Wrist extension
Explanation: Musculocutaneous nerve supplies biceps brachii, the chief supinator in flexion. Correct answer: Supination with flexed elbow. Clinical: Weakness plus sensory loss lateral forearm.
5) Which movement is preserved in posterior interosseous nerve injury?
a) Finger extension
b) Supination with flexed elbow
c) Wrist extension
d) Thumb abduction
Explanation: Biceps brachii (musculocutaneous) compensates supination in flexion. Correct answer: Supination with flexed elbow. Clinical: Posterior interosseous palsy spares biceps function.
6) Which muscle is a synergist in both pronation and supination, bringing forearm to mid-prone?
a) Supinator
b) Biceps brachii
c) Brachioradialis
d) Pronator teres
Explanation: Brachioradialis brings forearm into mid-prone from either side. Correct answer: Brachioradialis. Clinical: Preserved action in radial nerve palsy proximal to its branch.
7) Supination test in clinical examination mainly evaluates?
a) Median nerve
b) Musculocutaneous nerve
c) Ulnar nerve
d) Axillary nerve
Explanation: Supination in flexion depends on biceps brachii, innervated by musculocutaneous nerve. Correct answer: Musculocutaneous nerve. Clinical: Used to assess injury after trauma.
8) Which muscle is NOT involved in forearm supination?
a) Supinator
b) Biceps brachii
c) Brachioradialis
d) FDS
Explanation: FDS is a finger flexor, has no role in forearm rotation. Correct answer: FDS. Clinical: Misconception often tested in exams.
9) In radial head dislocation (nursemaid’s elbow), which movement is restricted?
a) Pronation
b) Supination
c) Flexion
d) Extension
Explanation: Dislocated radial head impairs supination since supinator attaches here. Correct answer: Supination. Clinical: Common in children lifted by hand.
10) In fracture of surgical neck of humerus sparing biceps, supination is?
a) Lost completely
b) Weak but present
c) Normal
d) Exaggerated
Explanation: Biceps brachii (musculocutaneous) remains intact; supination is preserved. Correct answer: Normal. Clinical: Differentiates between radial and musculocutaneous lesions.
Keyword Definitions
• Extensor compartments – Six fibro-osseous dorsal compartments on wrist that guide extensor tendons beneath extensor retinaculum.
• Extensor pollicis longus (EPL) – Tendon that extends the thumb interphalangeal joint; runs in 3rd compartment around Lister’s tubercle.
• Extensor carpi radialis longus (ECRL) – Wrist extensor and radial abductor; runs in 2nd compartment (partly).
• Extensor carpi radialis brevis (ECRB) – Wrist extensor in 2nd compartment; often involved in lateral epicondylitis.
• Extensor pollicis brevis (EPB) – Short thumb extensor in 1st compartment with APL.
• Lister’s tubercle – Dorsal tubercle of radius that acts as a pulley for EPL tendon (3rd compartment).
• De Quervain’s tenosynovitis – Stenosing tenosynovitis of 1st dorsal compartment (APL, EPB).
• Intersection syndrome – Overuse tenosynovitis where 1st compartment tendons cross 2nd compartment tendons.
• Extensor retinaculum – Fibrous band holding extensor tendons in compartments at wrist.
• Clinical importance – Identifying compartment involved helps diagnose dorsal wrist pain and plan surgical release.
Chapter: Anatomy / Upper Limb
Topic: Wrist and Hand
Subtopic: Dorsal Extensor Compartments of Wrist
Lead Question – 2013
3rd extensor compartment of wrist contains tendon of ?
a) ECRL
b) ECRB
c) EPL
d) EPB
Explanation: The third dorsal compartment contains the extensor pollicis longus (EPL) tendon as it uses Lister’s tubercle as a pulley, redirecting its line of pull to extend the thumb. Correct answer: EPL. Clinically, EPL rupture may follow distal radius fractures and presents as loss of thumb IP extension.
Guessed Questions for NEET PG
1) First dorsal compartment contains tendons of:
a) APL & EPB
b) EPL only
c) ECRL & ECRB
d) Extensor digitorum
Explanation: The first dorsal compartment contains abductor pollicis longus (APL) and extensor pollicis brevis (EPB). Stenosis here causes de Quervain’s tenosynovitis with radial wrist pain. Correct answer: APL & EPB. Treatment includes splinting or compartmental release.
2) Second dorsal compartment contains which tendons?
a) ECRL & ECRB
b) EPL only
c) APL & EPB
d) Extensor digiti minimi
Explanation: The second compartment contains extensor carpi radialis longus and brevis (ECRL, ECRB). These tendons glide under the retinaculum and are implicated in intersection syndrome when irritated by crossing first-compartment tendons. Correct answer: ECRL & ECRB.
3) Lister’s tubercle is clinically significant because it:
a) Is attachment for ECU
b) Acts as pulley for EPL tendon
c) Houses radial artery
d) Is origin of APL
Explanation: Lister’s tubercle on the distal radius acts as a dorsal pulley for the EPL tendon, changing its direction toward the thumb. After distal radius fractures, EPL attrition or rupture can occur here. Correct answer: Acts as pulley for EPL tendon.
4) De Quervain’s tenosynovitis typically presents with pain at:
a) Ulnar styloid
b) Radial styloid / lateral wrist
c) Dorsal midcarpal region
d) Pisiform area
Explanation: De Quervain’s affects APL and EPB in the first dorsal compartment causing pain and tenderness at the radial styloid. Finkelstein’s test reproduces pain. Correct answer: Radial styloid / lateral wrist. Management includes splinting and steroid injection.
5) Extensor digitorum communis (EDC) tendons lie in which compartment primarily?
a) Third
b) Fourth
c) Fifth
d) Sixth
Explanation: The fourth dorsal compartment houses the extensor digitorum communis (EDC) tendons and extensor indicis. Correct answer: Fourth. Clinical: Extensor tendon injuries in this compartment affect finger extension and may require repair or tenodesis.
6) Extensor digiti minimi runs in which compartment?
a) First
b) Second
c) Fifth
d) Sixth
Explanation: The fifth dorsal compartment contains the extensor digiti minimi tendon (to little finger). Tenosynovitis here causes localized dorsal ulnar wrist pain. Correct answer: Fifth compartment. Surgical release may be needed for refractory cases.
7) Extensor carpi ulnaris (ECU) tendon lies in which compartment?
a) Third
b) Fourth
c) Fifth
d) Sixth
Explanation: The sixth dorsal compartment contains the extensor carpi ulnaris (ECU) tendon running along the ulnar side. ECU subluxation or tendinopathy causes ulnar-sided wrist pain, especially in racket sports. Correct answer: Sixth compartment.
8) Intersection syndrome involves friction where first compartment tendons cross which compartment?
a) Second compartment tendons
b) Third compartment tendons
c) Fourth compartment tendons
d) Fifth compartment tendons
Explanation: Intersection syndrome results from friction where APL/EPB (1st compartment) cross over ECRL/ECRB (2nd compartment) about 4–8 cm proximal to wrist, producing forearm pain and crepitus. Correct answer: Second compartment tendons.
9) Rupture of EPL tendon is most commonly associated with which injury?
a) Distal radius fracture
b) Scaphoid fracture
c) Hamate fracture
d) Colles’ dislocation only
Explanation: EPL rupture classically follows distal radius fractures due to attrition at Lister’s tubercle or ischemia of the tendon sheath. Patients lose active IP extension of thumb. Correct answer: Distal radius fracture. Surgical tendon transfer may be required.
10) A swollen dorsal wrist with pain on thumb extension and positive Finkelstein’s test indicates involvement of which compartment?
a) First compartment
b) Third compartment
c) Fourth compartment
d) Sixth compartment
Explanation: Positive Finkelstein’s test with radial styloid tenderness indicates first compartment stenosing tenosynovitis (APL & EPB) — de Quervain’s disease. Correct answer: First compartment. Conservative treatment includes rest, splinting, and steroid injection.
Keyword Definitions
• Anterior interosseous nerve (AIN) – A pure motor branch of the median nerve that supplies deep forearm flexors.
• Flexor pollicis longus (FPL) – Muscle of thumb flexion at interphalangeal joint, supplied by AIN.
• Flexor digitorum profundus (FDP) – Medial part supplied by ulnar nerve, lateral part by AIN.
• Flexor digitorum superficialis (FDS) – Flexes proximal interphalangeal joints, supplied by median nerve proper (not AIN).
• Flexor carpi ulnaris (FCU) – Flexes and adducts wrist, supplied by ulnar nerve.
• Brachioradialis – Forearm flexor in mid-pronation, supplied by radial nerve.
• Abductor pollicis brevis (APB) – Thenar muscle, supplied by recurrent branch of median nerve.
• Kiloh–Nevin syndrome – Clinical syndrome due to anterior interosseous nerve palsy.
• Froment’s sign – Indicates ulnar nerve palsy when adductor pollicis is weak.
• Nerve lesions – Important in differential diagnosis of anterior compartment weakness.
Chapter: Anatomy / Upper Limb
Topic: Nerve Supply
Subtopic: Anterior Interosseous Nerve
Lead Question – 2013
All are supplied by anterior interosseous nerve except –
a) Flexor carpi ulnaris
b) Brachioradialis
c) Abductor pollicis brevis
d) Flexor pollicis longus
e) Flexor digitorum superficialis
Explanation: The anterior interosseous nerve supplies flexor pollicis longus, pronator quadratus, and the lateral half of flexor digitorum profundus. Muscles like FCU (ulnar nerve), brachioradialis (radial nerve), APB (recurrent median), and FDS (median nerve proper) are not supplied by AIN. Correct answer: All except FPL.
Guessed Questions for NEET PG
1) Anterior interosseous nerve is a branch of:
a) Ulnar nerve
b) Radial nerve
c) Median nerve
d) Musculocutaneous nerve
Explanation: The anterior interosseous nerve is a motor branch of the median nerve that arises in the proximal forearm. It runs along the interosseous membrane supplying deep flexors. Correct answer: Median nerve. It carries no cutaneous fibers, making its lesions purely motor.
2) Kiloh–Nevin syndrome refers to:
a) Ulnar nerve palsy
b) Radial nerve entrapment
c) Anterior interosseous nerve palsy
d) Posterior interosseous nerve palsy
Explanation: Kiloh–Nevin syndrome is anterior interosseous nerve palsy, presenting with inability to make the “OK sign” due to weakness of FPL and FDP (index finger). Correct answer: Anterior interosseous nerve palsy. It is often due to compression or neuritis.
3) Inability to flex thumb IP joint is seen in lesion of:
a) Median nerve at wrist
b) Ulnar nerve at elbow
c) Anterior interosseous nerve
d) Radial nerve in spiral groove
Explanation: The flexor pollicis longus, innervated by AIN, flexes thumb IP joint. Its palsy causes inability to flex the thumb tip. Correct answer: Anterior interosseous nerve. This finding is a diagnostic clue for AIN syndrome.
4) Which muscle is NOT supplied by AIN?
a) Pronator quadratus
b) FPL
c) FDP (lateral half)
d) FDS
Explanation: The anterior interosseous nerve supplies pronator quadratus, FPL, and lateral half of FDP. The FDS is supplied by the main trunk of the median nerve, not AIN. Correct answer: FDS. This helps localize nerve lesions in clinical practice.
5) Patient unable to flex index finger DIP joint likely has lesion in:
a) Radial nerve
b) Ulnar nerve
c) AIN
d) Musculocutaneous nerve
Explanation: The lateral part of flexor digitorum profundus (index and middle fingers) is supplied by AIN. Inability to flex DIP of index suggests AIN palsy. Correct answer: AIN. Ulnar supplies medial part for ring and little fingers.
6) Which test detects AIN palsy?
a) Phalen’s test
b) Froment’s sign
c) Pinch “OK” sign test
d) Tinel’s sign
Explanation: In AIN palsy, patient cannot make a round “O” with thumb and index, instead forming a triangular pinch due to weakness of FPL and FDP. Correct answer: Pinch “OK” sign test. This is diagnostic of AIN syndrome.
7) Which nerve supplies pronator quadratus?
a) Radial
b) Ulnar
c) Anterior interosseous
d) Posterior interosseous
Explanation: Pronator quadratus, a deep forearm pronator, is supplied exclusively by the anterior interosseous nerve. Correct answer: Anterior interosseous. Lesion impairs pronation, especially when forearm is flexed, and reduces grip strength.
8) A forearm fracture with isolated motor palsy (no sensory loss) indicates lesion of:
a) Ulnar nerve
b) Radial nerve
c) Anterior interosseous nerve
d) Median nerve proper
Explanation: Since the anterior interosseous nerve is a pure motor branch without cutaneous innervation, its injury causes motor weakness only. Correct answer: Anterior interosseous nerve. This differentiates it from other mixed nerves.
9) Which thenar muscle is NOT supplied by anterior interosseous nerve?
a) Abductor pollicis brevis
b) FPL
c) Opponens pollicis
d) Adductor pollicis
Explanation: Abductor pollicis brevis and other thenar muscles are supplied by the recurrent branch of the median nerve. Adductor pollicis is supplied by ulnar. Only FPL is under AIN supply. Correct answer: Abductor pollicis brevis.
10) A patient with supracondylar fracture develops inability to flex thumb IP and index DIP joints. Likely involved nerve is:
a) Radial
b) Ulnar
c) AIN
d) Musculocutaneous
Explanation: This classic presentation is due to AIN palsy following trauma, causing paralysis of FPL and FDP (index). Correct answer: AIN. Distinguishing feature is pure motor deficit with preserved cutaneous sensation.
Keyword Definitions
• Interosseous membrane – Fibrous sheet between radius and ulna, provides attachment for muscles and transmits forces.
• Anterior interosseous artery – Branch of common interosseous artery running on anterior surface of interosseous membrane supplying deep forearm muscles.
• Posterior interosseous artery – Branch that reaches the posterior compartment, often passes through/perforates the interosseous membrane to supply extensors.
• Common interosseous artery – Short trunk from ulnar artery dividing into anterior and posterior interosseous arteries.
• Interosseous space – The gap between radius and ulna occupied by membrane and vessels; communicates between compartments.
• Posterior interosseous nerve – Deep branch of radial nerve running in posterior compartment with posterior interosseous vessels.
• Perforating branches – Small vessels that traverse the interosseous membrane to connect anterior and posterior circulations.
• Clinical relevance – Knowledge is vital in forearm fractures and surgical approaches to avoid vascular injury.
• Supination/pronation force transmission – Interosseous membrane transmits axial loads from radius to ulna during weight-bearing.
• Surgical landmark – Interosseous membrane used as reference during forearm reconstructive procedures.
Chapter: Anatomy / Upper Limb
Topic: Forearm Vessels and Membranes
Subtopic: Interosseous Membrane and its Perforators
Lead Question – 2013
Interosseous membrane of forearm is pierced by?
a) Brachial artery
b) Anterior interosseous artery
c) Posterior interosseous artery
d) Ulnar recurrent artery
Explanation: The posterior interosseous artery typically pierces the interosseous membrane to reach the posterior compartment, accompanying the posterior interosseous nerve. The anterior interosseous artery runs on the anterior surface and sends perforators. Correct answer: Posterior interosseous artery. Clinically important in posterior compartment surgeries and fractures.
Guessed Questions for NEET PG
1) The anterior interosseous artery is a branch of:
a) Radial artery
b) Ulnar artery (via common interosseous)
c) Brachial artery directly
d) Posterior interosseous artery
Explanation: The anterior interosseous artery arises from the common interosseous branch of the ulnar artery and runs on the anterior surface of the interosseous membrane. Correct answer: Ulnar artery (via common interosseous). Clinical: AIN and artery are vulnerable in proximal forearm trauma.
2) Which nerve accompanies the posterior interosseous artery in the posterior compartment?
a) Superficial radial nerve
b) Posterior interosseous nerve (deep branch of radial)
c) Median nerve
d) Ulnar nerve
Explanation: The posterior interosseous nerve (deep branch of radial nerve) accompanies the posterior interosseous artery in the posterior compartment to supply extensor muscles. Correct answer: Posterior interosseous nerve. Clinical: Injury causes finger extension weakness without sensory loss.
3) Perforating branches of the interosseous arteries allow communication between:
a) Radial and ulnar arteries only
b) Anterior and posterior compartments of forearm
c) Superficial and deep palmar arches
d) Brachial and radial arteries
Explanation: Perforators through the interosseous membrane connect anterior and posterior interosseous arteries, providing collateral circulation between forearm compartments. Correct answer: Anterior and posterior compartments. Clinical: Important when primary vessels are injured.
4) Injury to posterior interosseous artery in proximal forearm most likely causes:
a) Pure sensory loss in hand
b) Ischemia of posterior compartment muscles
c) Loss of pronation only
d) Thumb adduction loss
Explanation: Damage to posterior interosseous artery reduces blood supply to posterior (extensor) compartment leading to ischemic pain and weakness. Correct answer: Ischemia of posterior compartment muscles. Clinical: May accompany fractures or surgical insults.
5) The common interosseous artery usually arises from:
a) Radial artery
b) Ulnar artery
c) Brachial artery at cubital fossa
d) Profunda brachii artery
Explanation: The common interosseous artery branches from the ulnar artery shortly after the ulnar origin, then divides into anterior and posterior interosseous arteries. Correct answer: Ulnar artery. Clinical: Variant anatomy can affect flap planning.
6) Which structure runs along the anterior surface of the interosseous membrane?
a) Posterior interosseous artery
b) Anterior interosseous artery and nerve
c) Superficial radial nerve
d) Ulnar nerve
Explanation: The anterior interosseous artery and anterior interosseous branch of median nerve run on the anterior surface of the interosseous membrane supplying deep flexors. Correct answer: Anterior interosseous artery and nerve. Clinical: AIN palsy causes pure motor deficits.
7) The posterior interosseous artery usually reaches the posterior compartment via a gap near which landmark?
a) Lister’s tubercle
b) Proximal border of interosseous membrane near supinator
c) Ulnar styloid process
d) Pisiform bone
Explanation: The posterior interosseous artery commonly passes to the posterior compartment near the proximal border of the interosseous membrane in the region of the supinator. Correct answer: Proximal border of interosseous membrane near supinator. Clinical: Supinator syndrome may compromise vessels and nerve.
8) In a Galeazzi fracture (distal radius with DRUJ disruption), which artery's flow might be compromised affecting interosseous communication?
a) Brachial artery
b) Anterior interosseous artery
c) Posterior tibial artery
d) Median artery
Explanation: A distal radius fracture can disturb branches including anterior interosseous artery or its perforators, impairing collateral flow between compartments. Correct answer: Anterior interosseous artery. Clinical: Assess distal perfusion and nerve function in such injuries.
9) The anterior interosseous artery supplies all EXCEPT:
a) Flexor pollicis longus
b) Pronator quadratus
c) Lateral part of flexor digitorum profundus
d) Extensor digitorum communis
Explanation: The AIN supplies FPL, pronator quadratus, and lateral FDP; it does not supply extensor digitorum communis (posterior compartment). Correct answer: Extensor digitorum communis. Clinical: AIN lesions cause weak thumb and index flexion.
10) Surgical exposure of the posterior forearm should avoid injury to which vessel that pierces the interosseous membrane?
a) Radial artery
b) Posterior interosseous artery
c) Ulnar artery
d) Cephalic vein
Explanation: The posterior interosseous artery pierces the interosseous membrane to reach the posterior compartment and must be preserved during surgical approaches to avoid ischemia of extensor muscles. Correct answer: Posterior interosseous artery. Careful dissection around supinator is required.
Keyword Definitions
• Great saphenous vein – Longest superficial vein, runs from the medial foot to the groin, drains into femoral vein at saphenous (femoral) opening.
• Dorsal venous arch – Venous network on dorsum of foot; medial end gives origin to great saphenous vein.
• Saphenous nerve – Sensory branch of femoral nerve that accompanies the great saphenous vein along medial leg.
• Small (lesser) saphenous vein – Superficial posterior leg vein draining to popliteal vein; accompanied by sural nerve.
• Saphenous opening (fossa ovalis) – Gap in fascia lata where great saphenous vein passes to join femoral vein.
• Perforator veins – Connect superficial and deep systems (e.g., Cockett perforators); incompetence causes varicose veins.
• Varicose veins – Dilated, tortuous superficial veins due to valvular incompetence, commonly involve great saphenous tributaries.
• Saphenous cutdown – Surgical exposure of great saphenous vein at medial ankle for venous access.
• CABG conduit – Great saphenous vein commonly harvested for coronary artery bypass grafting.
• Clinical relevance – Knowledge of relationships important for varicose vein surgery, saphenous nerve preservation, and venous access.
Chapter: Anatomy / Lower Limb
Topic: Superficial Venous System of Lower Limb
Subtopic: Great Saphenous Vein – Anatomy and Clinical Correlates
Lead Question – 2013
True statement about great saphenous vein
a) It begins at lateral end of dorsal venous arch
b) It runs anterior to medial malleolus
c) It is accompanied by sural nerve
d) Terminates into popliteal vein
Explanation: The great saphenous vein arises from the **medial** end of the dorsal venous arch, ascends **anterior to the medial malleolus**, and is accompanied by the saphenous nerve. It terminates into the femoral vein at the saphenous opening, not the popliteal. Correct answer: (b). Clinically vital for varicose vein surgery and graft harvest.
Guessed Questions for NEET PG
1) The great saphenous vein terminates into the:
a) Popliteal vein
b) Femoral vein at saphenous opening
c) Small saphenous vein
d) Posterior tibial vein
Explanation: The great saphenous vein ascends the medial leg and pierces the fascia lata at the saphenous (femoral) opening to drain into the femoral vein. Correct answer: Femoral vein at saphenous opening. Clinically, this junction is inspected during varicose vein surgery and duplex scanning.
2) Which nerve accompanies the great saphenous vein along the medial leg?
a) Sural nerve
b) Saphenous nerve
c) Superficial peroneal nerve
d) Tibial nerve
Explanation: The saphenous nerve (branch of femoral nerve) runs with the great saphenous vein along the medial aspect of the leg and ankle carrying cutaneous sensation. Correct answer: Saphenous nerve. Clinical: Preserve this nerve during vein harvest to avoid medial leg numbness.
3) The commonest complication of great saphenous vein valve incompetence is:
a) Deep vein thrombosis only
b) Varicose veins of medial leg and thigh
c) Plantar fasciitis
d) Morton's neuroma
Explanation: Incompetence of valves in great saphenous and its tributaries leads to venous hypertension and varicose veins, typically along the medial leg and thigh. Correct answer: Varicose veins. Clinical: Presents with aching, swelling, and skin changes; treated by ablation or stripping.
4) The origin of the great saphenous vein is at the:
a) Lateral end of dorsal venous arch
b) Medial end of dorsal venous arch (near first metatarsal)
c) Posterior aspect of heel
d) Popliteal fossa
Explanation: Great saphenous vein begins at the **medial** end of the dorsal venous arch near the medial side of the foot and first metatarsal region. Correct answer: Medial end of dorsal venous arch. Clinically, this is the landmark for saphenous cutdown access.
5) The small saphenous vein typically drains into the:
a) Femoral vein
b) Popliteal vein
c) Great saphenous vein
d) Anterior tibial vein
Explanation: The small (lesser) saphenous vein ascends posterior calf and usually drains into the popliteal vein in the popliteal fossa. Correct answer: Popliteal vein. Clinical distinction helps in planning venous ablation and thrombosis evaluation.
6) Which perforator group is classically associated with great saphenous reflux in the lower leg?
a) Cockett perforators (lower leg)
b) Dodd perforators (thigh only)
c) Boyd perforators (popliteal crease only)
d) No perforators in lower leg
Explanation: Cockett perforators are located in the lower calf and commonly allow reflux from deep to superficial veins contributing to great saphenous varicosities. Correct answer: Cockett perforators. Clinical: Identified and ligated in surgical treatment of varicose veins.
7) For coronary artery bypass grafting, the great saphenous vein is harvested because it is:
a) Short and deep
b) Long, superficial, and of suitable caliber
c) Accompanied by artery
d) Immune to atherosclerosis
Explanation: The great saphenous vein is long, superficial, readily accessible, and generally of adequate caliber for bypass grafting. Correct answer: Long, superficial, and of suitable caliber. Clinical: Harvest technique must preserve side branches and avoid injury to saphenous nerve.
8) In saphenous vein cutdown for emergency venous access, the incision is usually made just anterior to the:
a) Lateral malleolus
b) Medial malleolus
c) Tibial tuberosity
d) Popliteal fossa
Explanation: Saphenous vein cutdown is performed anterior to the medial malleolus where the great saphenous vein is superficial and fixed, facilitating cannulation. Correct answer: Medial malleolus. Clinical: Useful when peripheral access is difficult; take care to avoid saphenous nerve.
9) Which statement about great saphenous vein valves is correct?
a) Valves prevent flow from superficial to deep veins only
b) Valves are absent in great saphenous vein
c) Valve incompetence leads to retrograde flow and varicosities
d) Valves force blood toward foot
Explanation: Venous valves normally permit unidirectional flow toward the heart; incompetence in the great saphenous system causes retrograde flow and varicose veins. Correct answer: Valve incompetence leads to retrograde flow and varicosities. Clinical: Duplex ultrasound assesses valve function before intervention.
10) A patient with thrombosis limited to the great saphenous vein (superficial thrombophlebitis) most importantly requires evaluation for:
a) Pulmonary embolism risk and extension into deep venous system
b) Immediate limb amputation
c) Coronary artery disease
d) Spinal cord compression
Explanation: Superficial thrombophlebitis of great saphenous vein may extend into deep veins, risking DVT and pulmonary embolism; evaluate with duplex ultrasound and treat accordingly. Correct answer: Pulmonary embolism risk and extension into deep venous system. Clinical: Anticoagulation and surveillance may be needed.
Keyword Definitions
• Anterior compartment (leg) – The muscular compartment on the front of the leg containing tibialis anterior, EDL, EHL, and popliteo-tibial neurovascular structures.
• Tibialis anterior (TA) – Primary dorsiflexor and inverter of foot; tendon medial to bundle at ankle.
• Extensor hallucis longus (EHL) – Extends big toe; its tendon lies between TA and EDL at the dorsum.
• Extensor digitorum longus (EDL) – Extends toes 2–5; lateral to EHL and often associated with peroneus tertius.
• Peroneus tertius – Variable muscle, tendon joins EDL over lateral dorsum, aids eversion.
• Anterior tibial artery – Main artery of anterior compartment, continues as dorsalis pedis on dorsum of foot.
• Deep peroneal (fibular) nerve – Motor to anterior compartment, sensory to web space between 1st and 2nd toes.
• Extensor retinaculum – Holds extensor tendons and neurovascular bundle at the ankle.
• Clinical correlation – Localization of bundle important for dorsalis pedis pulse and ankle compartment surgery.
• Surgical relevance – Avoid injury to anterior tibial vessels and deep peroneal nerve during ankle procedures.
Chapter: Anatomy / Lower Limb
Topic: Leg — Anterior Compartment
Subtopic: Neurovascular relations at the ankle
Lead Question – 2013
Neurovascular bundle of anterior compartment of leg passes between the tendons of ?
a) EHL and EDL
b) EDL and peroneus tertius
c) Tibialis anterior and EHL
d) None of the above
Explanation: The anterior tibial vessels and deep peroneal nerve travel in the anterior compartment and, at the ankle beneath the extensor retinaculum, lie between the tendons of tibialis anterior (medial) and extensor hallucis longus (lateral). Correct answer: (c) Tibialis anterior and EHL. Clinically palpable as dorsalis pedis pulse distal to this region.
Guessed Questions for NEET PG
1) The artery continuing from anterior tibial artery onto the dorsum of the foot is:
a) Posterior tibial artery
b) Dorsalis pedis artery
c) Peroneal artery
d) Medial plantar artery
Explanation: The anterior tibial artery continues over the ankle as the dorsalis pedis artery on the dorsum of the foot. Correct answer: Dorsalis pedis artery. Clinically the dorsalis pedis pulse is used to assess peripheral perfusion and arterial injury in the foot.
2) Sensory supply of the web space between first and second toes is by:
a) Superficial peroneal nerve
b) Deep peroneal nerve
c) Saphenous nerve
d) Tibial nerve
Explanation: The deep peroneal (fibular) nerve supplies the skin between the first and second toes. Correct answer: Deep peroneal nerve. Clinically, numbness here suggests injury to the deep peroneal nerve at the ankle or leg.
3) A patient with foot drop after fibular neck fracture likely has injury to:
a) Superficial peroneal nerve
b) Deep peroneal nerve
c) Tibial nerve
d) Sural nerve
Explanation: Common fibular (peroneal) nerve wraps around fibular neck and its deep branch supplies anterior compartment dorsiflexors. Injury causes foot drop. Correct answer: Deep peroneal (branch of common peroneal). Clinically presents with steppage gait.
4) The extensor retinaculum prevents bowstringing of:
a) Flexor tendons only
b) Extensor tendons only
c) Both flexor and extensor tendons equally
d) Peroneal tendons only
Explanation: The extensor retinaculum secures extensor tendons at the ankle, preventing bowstringing during dorsiflexion. Correct answer: Extensor tendons only. Clinically, tight retinaculum can cause tenosynovitis and pain over the dorsum of ankle.
5) A weak dorsalis pedis pulse with intact posterior tibial pulse suggests occlusion of:
a) Anterior tibial artery
b) Posterior tibial artery
c) Peroneal artery
d) Femoral artery
Explanation: Diminished dorsalis pedis with normal posterior tibial pulse suggests anterior tibial artery compromise. Correct answer: Anterior tibial artery. Clinically important in acute limb ischemia and after tibial fractures.
6) In anterior compartment syndrome, which action is most affected?
a) Plantarflexion of ankle
b) Dorsiflexion of ankle
c) Inversion of foot only
d) Toe abduction
Explanation: Anterior compartment contains dorsiflexors (tibialis anterior, EDL, EHL); raised pressure causes ischemia and loss of dorsiflexion. Correct answer: Dorsiflexion of ankle. Clinically urgent fasciotomy prevents permanent deficit.
7) The tendon order across the dorsum (medial to lateral) just distal to the ankle is:
a) TA, EHL, EDL, peroneus tertius
b) EDL, EHL, TA, peroneus tertius
c) Peroneus tertius, EDL, EHL, TA
d) TA, EDL, EHL, peroneus tertius
Explanation: From medial to lateral the tendons are tibialis anterior, extensor hallucis longus, extensor digitorum longus, then peroneus tertius. Correct answer: TA, EHL, EDL, peroneus tertius. This ordering helps localize neurovascular structures and tendinous pathology.
8) Injury to deep peroneal nerve at the ankle will cause sensory loss where?
a) Lateral foot dorsum
b) Medial sole
c) First web space between toes 1 and 2
d) Posterior calf
Explanation: Deep peroneal nerve supplies sensation to the first web space dorsally. Correct answer: First web space. Clinically, combined motor (dorsiflexion) and this specific sensory loss indicate deep peroneal lesion.
9) The best site to palpate the dorsalis pedis pulse is lateral to which tendon?
a) Tibialis anterior tendon
b) Extensor hallucis longus tendon
c) Extensor digitorum longus tendon
d) Peroneus tertius tendon
Explanation: The dorsalis pedis artery is palpated lateral to the tendon of extensor hallucis longus on the dorsum of the foot. Correct answer: Extensor hallucis longus tendon. Clinically used in vascular exams of the foot.
10) Surgical release of anterior compartment at the leg should avoid damaging which structure running in the compartment?
a) Great saphenous vein
b) Posterior tibial nerve
c) Deep peroneal nerve and anterior tibial vessels
d) Superficial peroneal nerve only
Explanation: The deep peroneal nerve and anterior tibial vessels run in the anterior compartment and must be preserved during fasciotomy or debridement. Correct answer: Deep peroneal nerve and anterior tibial vessels. Clinically, careful technique prevents vascular and motor-sensory loss.
Keyword Definitions
• Flexor retinaculum (ankle) – Fibrous band over medial ankle forming the roof of the tarsal tunnel.
• Tarsal tunnel – Space deep to flexor retinaculum transmitting tendons, vessels, and nerve into the foot.
• Posterior tibial artery – Major artery passing through tarsal tunnel to supply plantar foot; palpable as posterior tibial pulse.
• Tibialis anterior tendon – Anterior compartment tendon crossing dorsum of foot; does NOT pass under flexor retinaculum.
• Peroneus tertius – Anterior-lateral tendon inserting on dorsum of 5th metatarsal; not in tarsal tunnel.
• Long saphenous (great saphenous) vein – Superficial vein running anterior to medial malleolus, superficial to retinaculum.
• Tom, Dick And Very Nervous Harry – Mnemonic for structures deep to flexor retinaculum: Tibialis posterior, flexor Digitorum longus, posterior tibial Artery, posterior tibial Vein, tibial Nerve, flexor Hallucis longus.
• Tinel’s sign (at ankle) – Tapping over flexor retinaculum producing tingling in tunnel distribution, suggests tibial nerve entrapment.
• Posterior tibial pulse – Palpated just posterior to medial malleolus deep to flexor retinaculum; important in vascular exam.
• Clinical relevance – Tarsal tunnel syndrome results from compression of structures under flexor retinaculum causing plantar numbness/pain.
Chapter: Anatomy / Lower Limb
Topic: Ankle Region
Subtopic: Flexor Retinaculum (Tarsal Tunnel) Contents
Lead Question – 2013
Structure passing deep to flexor retinaculum is ?
a) Posterior tibial artery
b) Long saphenous vein
c) Tibialis anterior tendon
d) Peroneus tertius
Explanation: The posterior tibial artery passes deep to the flexor retinaculum within the tarsal tunnel alongside tendons and the tibial nerve. The long saphenous vein is superficial, tibialis anterior and peroneus tertius are anterior tendons. Correct answer: (a) Posterior tibial artery. Clinically the posterior tibial pulse is palpable here.
Guessed Questions for NEET PG
1) The tarsal tunnel contains all EXCEPT:
a) Tibialis posterior tendon
b) Flexor digitorum longus tendon
c) Peroneus longus tendon
d) Posterior tibial nerve
Explanation: The peroneus longus runs laterally and passes under the cuboid (peroneal groove), not through the tarsal tunnel. The tunnel contains tibialis posterior, FDL, posterior tibial vessels, tibial nerve, and FHL. Correct answer: Peroneus longus. Tarsal tunnel syndrome spares lateral tendons.
2) Posterior tibial pulse is best palpated:
a) Anterior to lateral malleolus
b) Posterior to medial malleolus beneath flexor retinaculum
c) On dorsum of foot lateral to EHL tendon
d) In popliteal fossa only
Explanation: The posterior tibial artery runs deep to flexor retinaculum posterior to the medial malleolus; its pulse is palpated there. Correct answer: Posterior to medial malleolus beneath flexor retinaculum. Loss of this pulse suggests distal arterial compromise.
3) Tinel’s sign at the tarsal tunnel tests for entrapment of which nerve?
a) Superficial peroneal nerve
b) Deep peroneal nerve
c) Tibial nerve (posterior tibial nerve in tunnel)
d) Sural nerve
Explanation: Tinel’s tapping over flexor retinaculum reproduces paresthesia in tibial nerve distribution (sole) when entrapped. Correct answer: Tibial nerve. Positive test aids diagnosis of tarsal tunnel syndrome which presents with plantar numbness and burning pain.
4) Which tendon is most medial under the flexor retinaculum (medial to lateral order)?
a) Flexor hallucis longus
b) Tibialis posterior
c) Flexor digitorum longus
d) Peroneus brevis
Explanation: Medial-to-lateral order in tarsal tunnel is tibialis posterior, flexor digitorum longus, posterior tibial vessels/nerve, then flexor hallucis longus more laterally. Peroneal tendons are lateral. Correct answer: Tibialis posterior. Important during surgical decompression.
5) Compression of posterior tibial nerve in the tarsal tunnel causes loss of sensation over:
a) Dorsum of foot only
b) Plantar surface of foot and toes
c) Lateral calf only
d) Medial thigh
Explanation: Tibial nerve supplies plantar cutaneous nerves; entrapment in tarsal tunnel causes plantar burning, numbness, and possible intrinsic muscle weakness. Correct answer: Plantar surface of foot and toes. Tarsal tunnel mimics plantar fasciitis clinically sometimes.
6) A patient with rupture of posterior tibial artery in ankle trauma will most likely present with:
a) Loss of dorsalis pedis pulse only
b) Absent posterior tibial pulse, ischemic plantar changes
c) Isolated foot drop
d) Loss of great saphenous waveform only
Explanation: Rupture of posterior tibial artery abolishes its palpable pulse and can compromise plantar circulation causing ischemic changes. Dorsalis pedis may be maintained via anterior tibial flow. Correct answer: Absent posterior tibial pulse, ischemic plantar changes. Urgent vascular assessment required.
7) The mnemonic “Tom, Dick, And Very Nervous Harry” lists structures in tarsal tunnel in which order?
a) Tibialis posterior, flexor Digitorum longus, posterior tibial Artery, posterior tibial Vein, tibial Nerve, flexor Hallucis longus
b) Tibialis anterior, extensor Digitorum longus, anterior tibial Artery…
c) Peroneus longus, peroneus brevis, sural nerve…
d) Flexor hallucis longus first then others
Explanation: The mnemonic correctly orders tibialis posterior, FDL, posterior tibial artery, posterior tibial vein, tibial nerve, and flexor hallucis longus (from medial to lateral). Correct answer: (a). Surgeons use this to identify structures during decompression.
8) Which vessel provides collateral supply to plantar arch if posterior tibial artery is occluded?
a) Anterior tibial (via dorsalis pedis and perforating branches)
b) Great saphenous vein
c) Peroneal artery exclusively without connections
d) Small saphenous vein
Explanation: Anterior tibial continues as dorsalis pedis and via perforating branches can contribute to plantar arches, providing collateral flow when posterior tibial artery is occluded. Correct answer: Anterior tibial (via dorsalis pedis). Clinical: Important in planning bypass and assessing ischemia.
9) Long saphenous vein at the ankle is located relative to flexor retinaculum as:
a) Deep to retinaculum within tarsal tunnel
b) Superficial to retinaculum anterior to medial malleolus
c) Passing through lateral retinaculum
d) Within tarsal tunnel posterior to tibial nerve
Explanation: The great saphenous vein is superficial on the medial ankle, anterior to the medial malleolus and superficial to the flexor retinaculum, used for venous cutdown access. Correct answer: Superficial to retinaculum anterior to medial malleolus. Preserve saphenous nerve during harvest.
10) Surgical decompression for tarsal tunnel syndrome requires incision of which structure?
a) Flexor retinaculum (tarsal tunnel roof)
b) Extensor retinaculum
c) Plantar aponeurosis only
d) Lateral ankle ligament complex
Explanation: Tarsal tunnel release involves incising the flexor retinaculum to decompress tibial nerve and associated structures. Correct answer: Flexor retinaculum. Timing is important as chronic compression can cause irreversible neuropathy and intrinsic foot muscle atrophy.
Keyword Definitions
• Gastrocnemius – Superficial, two-headed calf muscle crossing knee and ankle; powerful plantarflexor.
• Soleus – Deep to gastrocnemius, single-headed, plantarflexes ankle (postural muscle).
• Triceps surae – Collective term for gastrocnemius + soleus muscles forming the calf.
• Calcaneal (Achilles) tendon – Common tendon of triceps surae inserting into calcaneus.
• Tibial nerve – Branch of sciatic nerve supplying posterior compartment of leg and plantar foot.
• Plantarflexion – Downward movement of foot at ankle produced by triceps surae.
• Sural nerve – Sensory nerve formed by contributions from tibial and common peroneal nerves; supplies lateral foot.
• Posterior tibial artery – Major artery supplying posterior compartment and plantar foot.
• Baker’s cyst – Popliteal synovial cyst that may compress neurovascular structures in popliteal fossa.
• Achilles tendon rupture – Clinical injury causing inability to plantarflex and toe-raise; Thompson test positive.
Chapter: Anatomy / Lower Limb
Topic: Posterior Compartment of Leg
Subtopic: Triceps Surae (Gastrocnemius & Soleus)
Lead Question – 2013
Which muscles is known as 'Triceps surae'?
a) Gastro-soleus
b) Popliteus
c) EHL
d) EDL
Explanation: “Triceps surae” refers to the gastrocnemius and soleus acting together as the calf complex. Their common insertion via the calcaneal (Achilles) tendon produces powerful plantarflexion. Popliteus, EHL, and EDL are distinct muscles with different functions. Correct answer: Gastro-soleus (triceps surae).
Guessed Questions for NEET PG
1) Which nerve supplies triceps surae?
a) Common peroneal
b) Tibial
c) Femoral
d) Sural
Explanation: Triceps surae (gastrocnemius and soleus) are supplied by the tibial nerve, a branch of the sciatic nerve. Motor fibers reach muscles in the posterior compartment and sensory branches form part of the sural nerve. Correct answer: Tibial nerve. Clinically important in sciatic lesions.
2) The common tendon of triceps surae inserts into the:
a) Navicular
b) Calcaneus
c) Cuboid
d) Talus
Explanation: The calcaneal (Achilles) tendon attaches the triceps surae to the posterior calcaneus. This insertion transmits strong plantarflexor force. Rupture here causes inability to plantarflex and a positive Thompson test. Correct answer: Calcaneus.
3) Thompson test assesses rupture of which structure?
a) Plantaris tendon
b) Calcaneal (Achilles) tendon
c) Tibialis posterior tendon
d) Peroneus brevis tendon
Explanation: Squeezing the calf normally causes plantarflexion; absence indicates Achilles tendon rupture. Thompson test is thus specific for calcaneal tendon discontinuity, often from sudden dorsiflexion injury. Correct answer: Calcaneal (Achilles) tendon.
4) Which artery mainly supplies the triceps surae muscles?
a) Anterior tibial artery
b) Posterior tibial artery and its branches (peroneal included)
c) Dorsalis pedis artery
d) Femoral artery only
Explanation: The posterior tibial artery and contributions from the peroneal (fibular) artery supply the posterior compartment including triceps surae. Anterior tibial and dorsalis pedis supply anterior structures. Correct answer: Posterior tibial artery and branches. Important in ischemic leg evaluation.
5) Gastrocnemius contributes more to plantarflexion when the knee is:
a) Flexed
b) Extended
c) Neutral – unaffected by knee position
d) Internally rotated
Explanation: Gastrocnemius crosses the knee; it generates more plantarflexion when the knee is extended, as knee flexion slackens it. Soleus (monoarticular) acts regardless of knee position. Correct answer: Extended. Clinical tests consider knee position when assessing calf strength.
6) A positive calf squeeze with no plantarflexion indicates lesion of:
a) Posterior tibial nerve distal to gastrocnemius
b) Achilles tendon rupture
c) Tibialis anterior nerve injury
d) Peroneal nerve palsy
Explanation: The Thompson (calf squeeze) test shows absent plantarflexion in Achilles tendon rupture, not in isolated nerve palsy. Tendon discontinuity prevents force transmission despite intact muscle. Correct answer: Achilles tendon rupture. Prompt management needed to restore push-off.
7) Plantaris muscle, when present, lies between which two structures related to triceps surae?
a) Tibialis anterior and EHL
b) Gastrocnemius and soleus, with a long tendon medial to Achilles
c) Peroneus longus and brevis
d) Flexor hallucis longus and tibialis posterior
Explanation: Plantaris is a small accessory muscle with a long slender tendon that runs between gastrocnemius and soleus and often parallels the Achilles tendon medially. It is sometimes used as a tendon graft. Correct answer: Gastrocnemius and soleus region.
8) Rupture of the Achilles tendon most commonly results in loss of which gait phase action?
a) Heel strike
b) Toe-off/pushoff (plantarflexion phase)
c) Mid-stance stability only
d) Swing phase clearance
Explanation: Achilles rupture prevents effective plantarflexion needed for toe-off/pushoff, leading to impaired propulsion and altered gait. Patients have weak push-off and may show a palpable gap. Correct answer: Toe-off/pushoff. Surgical repair often restores function.
9) Which clinical condition involves pain and tightness of triceps surae with increased compartment pressure?
a) Plantar fasciitis
b) Posterior compartment syndrome of leg
c) Lateral ankle sprain
d) Deep vein thrombosis only
Explanation: Exertional or acute posterior compartment syndrome involves the deep posterior compartment including triceps surae, causing pain, tense swelling, and neurovascular compromise. Urgent fasciotomy is required. Correct answer: Posterior compartment syndrome (affecting calf muscles).
10) Sural nerve sensory distribution relates closely to triceps surae because it supplies:
a) Medial plantar surface of foot
b) Lateral aspect of foot and posterior calf skin overlying gastrocnemius
d) Plantar aspect of toes 2–4
Explanation: The sural nerve provides cutaneous innervation to the posterior calf and lateral foot, areas overlying the gastrocnemius and Achilles tendon. Injury causes sensory loss here and may accompany procedures on the calf. Correct answer: Lateral foot and posterior calf skin.
Keyword Definitions
• Femoral head – Spherical upper end of femur that articulates with acetabulum to form hip joint.
• Medial circumflex femoral artery – Major artery supplying femoral head and neck via retinacular branches.
• Lateral circumflex femoral artery – Smaller contribution to anterior femoral neck and head.
• Ligamentum teres artery – Small artery within ligament of head of femur; significant in children only.
• Profunda femoris artery – Deep femoral artery; gives rise to medial and lateral circumflex branches.
• Retinacular vessels – Arterial branches running along femoral neck beneath joint capsule to supply femoral head.
• Avascular necrosis (AVN) – Bone death due to interruption of blood supply; common complication of femoral neck fracture.
• Intracapsular fracture – Femoral neck fracture within capsule; disrupts blood supply leading to AVN.
• Hip dislocation – Displacement of femoral head; can stretch or rupture retinacular arteries.
• Artery of ligamentum teres – Vestigial in adults but may partially supply femoral head in young children.
Chapter: Anatomy / Lower Limb
Topic: Hip Joint
Subtopic: Blood Supply of Femoral Head
Lead Question – 2013
The blood supply to femoral head is mostly by?
a) Lateral epiphyseal artery
b) Medial epiphyseal artery
c) Ligamentous teres artery
d) Profunda femoris
Explanation: The main supply to the femoral head in adults is from retinacular branches of the medial circumflex femoral artery. The lateral circumflex contributes minimally. The artery of ligamentum teres is significant only in children. Profunda femoris is the parent trunk. Correct answer: Medial epiphyseal artery.
Guessed Questions for NEET PG
1) Which artery is most at risk of injury in intracapsular fracture of femoral neck?
a) Medial circumflex femoral
b) Lateral circumflex femoral
c) Profunda femoris
d) Obturator
Explanation: Intracapsular fractures damage retinacular branches of the medial circumflex femoral artery, the primary supplier of the femoral head. This disruption causes avascular necrosis. Correct answer: Medial circumflex femoral artery.
2) In children, which artery contributes significantly to femoral head supply?
a) Artery of ligamentum teres
b) Medial circumflex femoral
c) Lateral circumflex femoral
d) Inferior gluteal
Explanation: In children, the artery of ligamentum teres (branch of obturator artery) is important for femoral head vascularity. With age, this vessel regresses and becomes less significant. Correct answer: Artery of ligamentum teres.
3) Which complication most commonly follows fracture of femoral neck in elderly?
a) Osteoarthritis
b) Avascular necrosis of femoral head
c) Osteomyelitis
d) Sciatic nerve injury
Explanation: Disruption of medial circumflex femoral artery branches leads to avascular necrosis of the femoral head, particularly after intracapsular neck fractures. Correct answer: Avascular necrosis of femoral head.
4) Lateral circumflex femoral artery is mainly a branch of:
a) Internal iliac artery
b) Profunda femoris artery
c) Common femoral artery
d) External iliac artery
Explanation: The lateral circumflex femoral artery is a branch of profunda femoris artery. It supplies anterior thigh and gives ascending branches to the femoral neck. Correct answer: Profunda femoris artery.
5) Avascular necrosis of femoral head is best diagnosed initially by:
a) Plain X-ray
b) CT scan
c) MRI
d) Ultrasound
Explanation: MRI is the most sensitive modality to detect early avascular necrosis of femoral head before radiographic changes appear. Correct answer: MRI.
6) Which artery forms cruciate anastomosis around hip joint?
a) Superior gluteal
b) Inferior gluteal
c) Medial circumflex femoral
d) All of the above
Explanation: Cruciate anastomosis is formed by inferior gluteal, medial circumflex femoral, lateral circumflex femoral (transverse branch), and first perforator of profunda femoris. Correct answer: All of the above (with contributions).
7) Which ligament encloses the artery of ligamentum teres?
a) Iliofemoral ligament
b) Ischiofemoral ligament
c) Ligament of head of femur
d) Pubofemoral ligament
Explanation: The artery of ligamentum teres passes through the ligament of head of femur (ligamentum teres). Correct answer: Ligament of head of femur.
8) In posterior hip dislocation, blood supply to femoral head is compromised because:
a) Ligamentum teres is torn
b) Retinacular vessels from medial circumflex femoral artery are damaged
c) Obturator nerve compression
d) Venous drainage blocked
Explanation: Posterior dislocation stretches and tears retinacular vessels of medial circumflex femoral artery, causing avascular necrosis. Correct answer: Damage to retinacular vessels from medial circumflex artery.
9) Which artery does not participate in trochanteric anastomosis?
a) Superior gluteal
b) Inferior gluteal
c) Medial circumflex femoral
d) Anterior tibial
Explanation: Trochanteric anastomosis includes superior gluteal, inferior gluteal, medial circumflex femoral, and lateral circumflex femoral arteries. Anterior tibial does not contribute. Correct answer: Anterior tibial artery.
10) Best management for avascular necrosis of femoral head in advanced stage is:
a) Core decompression
b) Bisphosphonates
c) Total hip replacement
d) Bone marrow injection
Explanation: In advanced avascular necrosis with collapse of femoral head, total hip replacement is the definitive treatment. Early stages may respond to decompression. Correct answer: Total hip replacement.