How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Upper limb: ulnar nerve?

Learn every nerve by its route, its muscles and what a lesion looks like at the bedside. That one habit answers a large share of questions. Then use the flashcards and the other Anatomy questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.

Upper limb: ulnar nerve MCQ (B6-ANAT-1)

Q: What is the answer to this Anatomy question?

The best answer is B, In the elbow injury the medial half of flexor digitorum profundus is also paralysed, so the unopposed long-flexor pull that causes the claw is lost. Clawing results from paralysed ulnar lumbricals and interossei, leaving the extensor digitorum to hyperextend the metacarpophalangeal joints while the long flexors flex the interphalangeal joints.

Q: What concept does this question test?

It tests Upper limb: ulnar nerve in Anatomy. A high lesion also paralyses the ulnar half of flexor digitorum profundus, so flexion of the distal joints is weaker and the claw looks milder. This is the 'ulnar paradox'.

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Anatomy · Upper limb: ulnar nerve

Sample item

Two patients have complete ulnar nerve palsy: one from a cut at the wrist, the other from an injury at the elbow. The patient with the wrist injury has the more obvious claw deformity of the ring and little fingers. What explains this?

AThe wrist injury paralyses flexor carpi ulnaris, which increases the flexion of the interphalangeal jointsBIn the elbow injury the medial half of flexor digitorum profundus is also paralysed, so the unopposed long-flexor pull that causes the claw is lostCThe elbow injury spares the lumbricals, which keep the metacarpophalangeal joints flexedDThe elbow injury also denervates the extensor digitorum, which removes hyperextension at the metacarpophalangeal joints

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. In the elbow injury the medial half of flexor digitorum profundus is also paralysed, so the unopposed long-flexor pull that causes the claw is lost

Clawing results from paralysed ulnar lumbricals and interossei, leaving the extensor digitorum to hyperextend the metacarpophalangeal joints while the long flexors flex the interphalangeal joints. A high lesion also paralyses the ulnar half of flexor digitorum profundus, so flexion of the distal joints is weaker and the claw looks milder. This is the 'ulnar paradox'.

Option by option

A. The wrist injury paralyses flexor carpi ulnaris, which increases the flexion of the interphalangeal joints
Flexor carpi ulnaris is supplied above the wrist, so it is spared in the wrist injury, and its loss does not cause clawing.
B. In the elbow injury the medial half of flexor digitorum profundus is also paralysed, so the unopposed long-flexor pull that causes the claw is lost (correct)
Correct. A higher lesion removes the flexor pull that exaggerates the claw, so the deformity looks less severe.
C. The elbow injury spares the lumbricals, which keep the metacarpophalangeal joints flexed
The ulnar lumbricals are supplied by the ulnar nerve and are paralysed in both injuries.
D. The elbow injury also denervates the extensor digitorum, which removes hyperextension at the metacarpophalangeal joints
The extensor digitorum is supplied by the posterior interosseous (radial) nerve and is unaffected by an ulnar lesion.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Upper limb: ulnar nerve: practice question

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The answer and the reasoning

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