Elbow: supracondylar fracture and compartment syndrome: 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 and compartment syndrome

Sample item

A 7-year-old boy has a displaced supracondylar fracture of the humerus. Hours later he has severe forearm pain on passive finger extension, a pale hand and a weak radial pulse. If the ischaemia is untreated, which muscles are the most severely affected in the resulting Volkmann contracture?

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

The answer and the reasoning

A. Flexor digitorum profundus and flexor pollicis longus

Brachial artery injury or compression at a supracondylar fracture causes ischaemia of the forearm flexor compartment. The deep flexors, flexor digitorum profundus and flexor pollicis longus, lie closest to the interosseous membrane and have the poorest collateral supply, so they are infarcted first and most severely. The result is fixed flexion of the fingers and thumb.

Option by option

  • A. Flexor digitorum profundus and flexor pollicis longus (correct)

    Correct. The deep flexors are the most ischaemia-prone muscles in the flexor compartment.

  • B. Extensor digitorum and extensor pollicis longus

    The extensors lie in the posterior compartment, which is less affected.

  • C. Pronator teres and flexor carpi radialis

    These superficial flexors lie more peripherally and are less severely affected.

  • D. Brachioradialis and extensor carpi radialis longus

    These muscles lie in the lateral (mobile wad) group and are rarely involved.

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, Flexor digitorum profundus and flexor pollicis longus. Brachial artery injury or compression at a supracondylar fracture causes ischaemia of the forearm flexor compartment.

Why is "Extensor digitorum and extensor pollicis longus" not the answer?

The extensors lie in the posterior compartment, which is less affected.

Why is "Pronator teres and flexor carpi radialis" not the answer?

These superficial flexors lie more peripherally and are less severely affected.

Why is "Brachioradialis and extensor carpi radialis longus" not the answer?

These muscles lie in the lateral (mobile wad) group and are rarely involved.

What concept does this question test?

It tests Elbow: supracondylar fracture and compartment syndrome in Anatomy. The deep flexors, flexor digitorum profundus and flexor pollicis longus, lie closest to the interosseous membrane and have the poorest collateral supply, so they are infarcted first and most severely. The result is fixed flexion of the fingers and thumb.

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 and compartment syndrome?

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.