Elbow: supracondylar fracture complications: practice question

A Anatomy question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Anatomy · Elbow: supracondylar fracture complications

Sample item

A 6-year-old falls on an outstretched hand and has a displaced extension-type supracondylar fracture of the humerus. The hand is pale and cool, and he cannot flex the thumb interphalangeal joint or the distal phalanx of the index finger. Which nerve explains the motor deficit, and which complication is most feared?

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

The answer and the reasoning

A. Anterior interosseous nerve; Volkmann ischaemic contracture from brachial artery injury

In the extension type the proximal fragment can injure the brachial artery and the median nerve, most often its anterior interosseous branch, which supplies flexor pollicis longus and the lateral flexor digitorum profundus. Compartment ischaemia of the forearm flexors, if the vascular injury is missed, leads to Volkmann ischaemic contracture. Cubitus varus is a later malunion deformity.

Option by option

  • A. Anterior interosseous nerve; Volkmann ischaemic contracture from brachial artery injury (correct)

    Correct. The deficit matches the anterior interosseous nerve, and arterial compromise threatens the forearm flexor compartment.

  • B. Musculocutaneous nerve; cubitus varus from malunion

    The musculocutaneous nerve is at the shoulder and arm level and does not supply the forearm flexors.

  • C. Posterior interosseous nerve; myositis ossificans of brachialis

    The posterior interosseous nerve supplies extensors and would not cause these flexion deficits.

  • D. Ulnar nerve; cubitus valgus from physeal damage

    The ulnar nerve supplies the little and ring finger flexors, not the thumb and index.

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.

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Questions about this Anatomy question

What is the answer to this Anatomy question?

The best answer is A, Anterior interosseous nerve; Volkmann ischaemic contracture from brachial artery injury. In the extension type the proximal fragment can injure the brachial artery and the median nerve, most often its anterior interosseous branch, which supplies flexor pollicis longus and the lateral flexor digitorum profundus.

Why is "Musculocutaneous nerve; cubitus varus from malunion" not the answer?

The musculocutaneous nerve is at the shoulder and arm level and does not supply the forearm flexors.

Why is "Posterior interosseous nerve; myositis ossificans of brachialis" not the answer?

The posterior interosseous nerve supplies extensors and would not cause these flexion deficits.

Why is "Ulnar nerve; cubitus valgus from physeal damage" not the answer?

The ulnar nerve supplies the little and ring finger flexors, not the thumb and index.

What concept does this question test?

It tests Elbow: supracondylar fracture complications in Anatomy. Compartment ischaemia of the forearm flexors, if the vascular injury is missed, leads to Volkmann ischaemic contracture. Cubitus varus is a later malunion deformity.

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 Elbow: supracondylar fracture complications?

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.