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NEET PG anatomy upper limb important MCQ questions with explanations 2024

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I now have excellent textbook data to compile 20 high-quality NEET PG Upper Limb anatomy questions. Let me build the full set from the data gathered.

NEET PG Anatomy - Upper Limb: 20 MCQs with Explanations

BRACHIAL PLEXUS

Q1. The brachial plexus is formed by the anterior rami of which spinal segments?
  • A) C4, C5, C6, C7, C8
  • B) C5, C6, C7, C8, T1
  • C) C4, C5, C6, C7, T1
  • D) C5, C6, C7, T1, T2
Answer: B) C5, C6, C7, C8, T1
The brachial plexus is formed by anterior rami of C5 to C8 and most of T1. The plexus originates in the neck, passes laterally and inferiorly over rib I, and enters the axilla. All major nerves supplying the upper limb arise from this plexus. (Gray's Anatomy for Students)
Q2. The superior trunk of the brachial plexus is formed by the union of which roots?
  • A) C5 and C7
  • B) C7 alone
  • C) C5 and C6
  • D) C8 and T1
Answer: C) C5 and C6
  • Superior trunk = C5 + C6
  • Middle trunk = C7 alone (continuation)
  • Inferior trunk = C8 + T1
The inferior trunk lies on rib I posterior to the subclavian artery. (Gray's Anatomy for Students)
Q3. Erb's palsy (Erb-Duchenne palsy) results from injury to which roots of the brachial plexus?
  • A) C8, T1
  • B) C7, C8
  • C) C5, C6
  • D) C6, C7
Answer: C) C5, C6
Erb's palsy is an upper brachial plexus injury involving C5-C6 roots (superior trunk), typically from forcible separation of the neck and shoulder. The arm is adducted, internally rotated, and the forearm pronated - the classic "waiter's tip" position. This is the result of loss of deltoid, supraspinatus, infraspinatus, biceps, and brachioradialis function.
Klumpke's palsy = C8, T1 injury (inferior trunk), causing claw hand.
Q4. Which muscle is the most lateral structure in the axilla?
  • A) Serratus anterior
  • B) Subscapularis
  • C) Coracobrachialis
  • D) Pectoralis minor
Answer: C) Coracobrachialis
The lateral wall of the axilla is formed by the coracobrachialis and the short head of biceps brachii (the narrowest wall). The medial wall is formed by serratus anterior; the posterior wall by subscapularis, teres major, and latissimus dorsi; the anterior wall by pectoralis major and minor.

RADIAL NERVE

Q5. A patient presents with wrist drop after a mid-shaft fracture of the humerus. Which nerve is most likely injured?
  • A) Median nerve
  • B) Ulnar nerve
  • C) Radial nerve
  • D) Musculocutaneous nerve
Answer: C) Radial nerve
The radial nerve winds around the posterior aspect of the humerus in the radial groove (spiral groove). Mid-shaft humeral fractures characteristically injure the radial nerve at this level. The patient is unable to extend the wrist (wrist drop) or extend the metacarpophalangeal joints.
Importantly, triceps brachii function is PRESERVED in mid-shaft fractures because the branches to triceps leave the radial nerve BEFORE it enters the radial groove. (General Anatomy and Musculoskeletal System - THIEME Atlas; ROSEN's Emergency Medicine)
Q6. A patient with a midshaft humerus fracture has wrist drop but intact triceps function. The radial nerve injury is at which level?
  • A) In the axilla
  • B) In the radial groove (spiral groove)
  • C) At the lateral epicondyle
  • D) In the supinator canal
Answer: B) In the radial groove (spiral groove)
Branches to triceps leave the radial nerve PROXIMAL to the radial groove. Therefore:
  • Axillary lesion: wrist drop + triceps weakness
  • Radial groove lesion: wrist drop, NO triceps weakness (triceps spared)
  • Supinator canal (deep branch): NO wrist drop, NO sensory loss on hand (THIEME Atlas of Anatomy)
Q7. "Saturday night palsy" or "park bench palsy" results from compression of which nerve?
  • A) Ulnar nerve
  • B) Radial nerve
  • C) Median nerve
  • D) Axillary nerve
Answer: B) Radial nerve
Chronic compression of the radial nerve against the bony floor of the radial groove (e.g., draping the arm over the back of a park bench, or sleeping with the arm compressed) causes "park bench palsy" or "Saturday night palsy." Features: wrist drop without triceps weakness, with sensory disturbances. Prognosis is usually favorable. (THIEME Atlas of Anatomy)
Q8. Injury to the deep branch of the radial nerve in the supinator canal produces:
  • A) Wrist drop with sensory loss on the dorsum of the hand
  • B) Wrist drop without sensory loss
  • C) Loss of finger extension and thumb extension, NO wrist drop, NO sensory loss
  • D) Claw hand with sensory loss
Answer: C) Loss of finger extension and thumb extension, NO wrist drop, NO sensory loss
Before entering the supinator canal, the deep branch (posterior interosseous nerve) gives off the purely sensory superficial branch and motor branches to supinator, brachioradialis, and ECRL. Therefore, distal radial nerve compression (supinator syndrome) causes palsies of extensor pollicis longus/brevis, abductor pollicis longus, extensor digitorum, extensor indicis, and extensor carpi ulnaris - but WITHOUT wrist drop and WITHOUT hand sensory loss. (THIEME Atlas)

ULNAR NERVE

Q9. The characteristic deformity seen in ulnar nerve injury is:
  • A) Wrist drop
  • B) Ape hand
  • C) Claw hand (main en griffe)
  • D) Waiter's tip position
Answer: C) Claw hand (main en griffe)
Ulnar nerve palsy is the most common peripheral nerve paralysis. The classic feature is claw hand deformity due to loss of the lumbricals (3rd and 4th) and interossei - these muscles normally flex the MCP joints and extend the IP joints.
The clawing is more pronounced in the ring and little fingers (4th and 5th digits) because the 1st and 2nd lumbricals are supplied by the median nerve. (THIEME Atlas of Anatomy)
Q10. "Paradox of the clawing" in ulnar nerve injury refers to:
  • A) Clawing is absent when the nerve is cut at the wrist
  • B) Clawing is MORE pronounced in LOW ulnar nerve lesions (at wrist) than HIGH lesions (at elbow)
  • C) Clawing disappears when the wrist is flexed
  • D) Clawing affects only the thumb
Answer: B) Clawing is MORE pronounced in LOW ulnar nerve lesions (at wrist) than HIGH lesions (at elbow)
This is the Ulnar Paradox: In high ulnar nerve injury (at elbow), the flexor digitorum profundus (FDP) to ring and little fingers is also paralyzed - so there is less flexion at the IP joints, making the claw less obvious. In low lesions (at wrist), FDP is intact, so IP joint flexion is strong - producing a MORE pronounced claw.
Q11. Where is the ulnar nerve most commonly injured at the elbow?
  • A) In the cubital tunnel (ulnar groove behind medial epicondyle)
  • B) In the radial tunnel
  • C) At the lateral epicondyle
  • D) Through the brachialis muscle
Answer: A) In the cubital tunnel (ulnar groove behind medial epicondyle)
The ulnar nerve passes behind the medial epicondyle in the ulnar groove, where it is superficial and exposed. Pressure from resting on the arm or elbow trauma at this site is the most common cause of proximal ulnar nerve palsy. (THIEME Atlas of Anatomy)

MEDIAN NERVE

Q12. "Ape hand" deformity is seen in injury to which nerve?
  • A) Ulnar nerve (high lesion)
  • B) Radial nerve
  • C) Median nerve
  • D) Musculocutaneous nerve
Answer: C) Median nerve
Median nerve injury causes "ape hand" or "simian hand" - due to wasting of the thenar eminence (opponens pollicis, abductor pollicis brevis, and flexor pollicis brevis are all median nerve). The thumb lies in the same plane as the other fingers (loss of opposition), resembling an ape's hand.
Note: Ulnar nerve injury causes claw hand; Radial nerve injury causes wrist drop.
Q13. Carpal tunnel syndrome involves compression of which structure at the wrist?
  • A) Ulnar nerve and artery
  • B) Median nerve and flexor tendons
  • C) Radial nerve
  • D) Flexor carpi radialis tendon only
Answer: B) Median nerve and flexor tendons
The carpal tunnel is bounded by the carpal bones dorsally and the flexor retinaculum volarly. It transmits: the median nerve (the most palmar structure) and 9 flexor tendons (4 FDS + 4 FDP + 1 FPL). The ulnar nerve passes through Guyon's canal (NOT the carpal tunnel). (Campbell's Operative Orthopaedics)
Q14. Which of the following muscles is NOT supplied by the median nerve?
  • A) Opponens pollicis
  • B) Abductor pollicis brevis
  • C) Adductor pollicis
  • D) Flexor pollicis brevis (superficial head)
Answer: C) Adductor pollicis
The thenar muscles supplied by the median nerve are remembered by "LOAF":
  • Lumbricals (1st and 2nd)
  • Opponens pollicis
  • Abductor pollicis brevis
  • Flexor pollicis brevis (superficial head)
Adductor pollicis is supplied by the ULNAR nerve (deep branch). This is why pinching is weak in ulnar nerve injury.

AXILLARY NERVE

Q15. Axillary nerve injury most commonly follows which injury?
  • A) Fracture of the clavicle
  • B) Anterior dislocation of the shoulder / fracture of surgical neck of humerus
  • C) Supracondylar fracture of humerus
  • D) Midshaft humerus fracture
Answer: B) Anterior dislocation of the shoulder / fracture of surgical neck of humerus
The axillary nerve winds around the surgical neck of the humerus. Anterior shoulder dislocation and fractures of the surgical neck of the humerus are the classic causes of axillary nerve injury. The result is paralysis of the deltoid (loss of shoulder abduction beyond 15°) and teres minor, with sensory loss over the "regimental badge" area (lateral aspect of the upper arm). (Neuroanatomy through Clinical Cases; Rockwood & Green's)
Q16. The "regimental badge area" of sensory loss corresponds to injury of which nerve?
  • A) Radial nerve
  • B) Musculocutaneous nerve
  • C) Axillary nerve
  • D) Medial cutaneous nerve of the arm
Answer: C) Axillary nerve
The upper lateral cutaneous nerve of the arm (the sensory branch of the axillary nerve) supplies the skin over the lower deltoid region - the area where a military badge is traditionally worn. Sensory loss here is a hallmark of axillary nerve injury.

ROTATOR CUFF

Q17. The rotator cuff is made up of which four muscles?
  • A) Deltoid, supraspinatus, infraspinatus, subscapularis
  • B) Supraspinatus, infraspinatus, subscapularis, teres minor
  • C) Supraspinatus, infraspinatus, teres major, subscapularis
  • D) Deltoid, teres minor, infraspinatus, teres major
Answer: B) Supraspinatus, infraspinatus, subscapularis, teres minor
The rotator cuff (SITS):
  • Supraspinatus - abduction (initiates 0-15°)
  • Infraspinatus - lateral rotation
  • Teres minor - lateral rotation
  • Subscapularis - medial rotation (largest of the four)
Teres MAJOR is NOT part of the rotator cuff. (Harrison's Principles; Rockwood & Green's)
Q18. The most commonly torn tendon of the rotator cuff is:
  • A) Subscapularis
  • B) Teres minor
  • C) Infraspinatus
  • D) Supraspinatus
Answer: D) Supraspinatus
Supraspinatus is the most commonly torn rotator cuff tendon due to its vulnerable position under the coracoacromial arch and relative hypovascularity near its insertion. It is the key tendon in impingement syndrome. The "painful arc" (60°-120° of abduction) is classic for supraspinatus pathology.

BONES & JOINTS

Q19. Which bone is fractured in a "fall on an outstretched hand (FOOSH)" in an elderly patient, most commonly at the distal radius?
  • A) Scaphoid
  • B) Radius (Colles' fracture)
  • C) Ulna
  • D) Capitate
Answer: B) Radius (Colles' fracture)
Colles' fracture is a transverse fracture of the distal radius within 2.5 cm of the wrist, with dorsal displacement/angulation - producing the classic "dinner fork" deformity. It is the most common fracture in elderly females (post-menopausal osteoporosis).
In younger patients with FOOSH, the scaphoid is the most commonly fractured carpal bone (risk of avascular necrosis due to retrograde blood supply).
Q20. The "anatomical snuffbox" is bounded by which tendons?
  • A) Medially: extensor pollicis longus; Laterally: extensor pollicis brevis + abductor pollicis longus
  • B) Medially: flexor carpi radialis; Laterally: extensor carpi radialis longus
  • C) Medially: extensor carpi ulnaris; Laterally: extensor pollicis longus
  • D) Medially: extensor pollicis brevis; Laterally: flexor pollicis longus
Answer: A) Medially: extensor pollicis longus; Laterally: extensor pollicis brevis + abductor pollicis longus
The anatomical snuffbox:
  • Medial (ulnar) border: extensor pollicis longus
  • Lateral (radial) border: extensor pollicis brevis + abductor pollicis longus
  • Floor: scaphoid and trapezium bones, radial artery
Tenderness in the anatomical snuffbox after a FOOSH = suspected scaphoid fracture until proven otherwise (even if X-ray is initially negative).

Quick Summary Table

Q#TopicKey Point
1-2Brachial plexus rootsC5-T1; Superior trunk = C5+C6
3Erb's palsyC5, C6; "waiter's tip"
4Axilla wallsLateral wall = coracobrachialis
5-8Radial nerveWrist drop; spiral groove; Saturday night palsy
9-11Ulnar nerveClaw hand; ulnar paradox; medial epicondyle
12-14Median nerveApe hand; carpal tunnel; LOAF muscles
15-16Axillary nerveShoulder dislocation; regimental badge area
17-18Rotator cuffSITS; supraspinatus most torn
19-20BonesColles' fracture; anatomical snuffbox
Sources: Gray's Anatomy for Students; THIEME Atlas of General Anatomy and Musculoskeletal System; Campbell's Operative Orthopaedics 15e; Neuroanatomy through Clinical Cases 3e; Rockwood & Green's Fractures in Adults 10e; Harrison's Principles of Internal Medicine 22e.
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