Upper limb and brachial plexus: pronator quadratus: 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 · Upper limb and brachial plexus: pronator quadratus

Sample item

After a supracondylar fracture the anterior interosseous nerve is injured, and the patient cannot flex the thumb interphalangeal joint. Which deep forearm muscle that pronates the forearm is paralysed with it?

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

The answer and the reasoning

A. Pronator quadratus

The anterior interosseous nerve, a branch of the median nerve, supplies flexor pollicis longus, the lateral half of flexor digitorum profundus and pronator quadratus. Pronator teres is supplied higher up by the median nerve itself.

Option by option

  • A. Pronator quadratus (correct)

    Correct. This square muscle on the lower forearm is supplied by the anterior interosseous nerve.

  • B. Pronator teres

    This muscle is supplied by the median nerve above the origin of the anterior interosseous branch, so it is spared.

  • C. Supinator

    This muscle supinates and is supplied by the posterior interosseous nerve.

  • D. Brachioradialis

    This muscle flexes the elbow and is supplied by the radial nerve.

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.

More Anatomy questions

Questions about this Anatomy question

What is the answer to this Anatomy question?

The best answer is A, Pronator quadratus. The anterior interosseous nerve, a branch of the median nerve, supplies flexor pollicis longus, the lateral half of flexor digitorum profundus and pronator quadratus.

Why is "Pronator teres" not the answer?

This muscle is supplied by the median nerve above the origin of the anterior interosseous branch, so it is spared.

Why is "Supinator" not the answer?

This muscle supinates and is supplied by the posterior interosseous nerve.

Why is "Brachioradialis" not the answer?

This muscle flexes the elbow and is supplied by the radial nerve.

What concept does this question test?

It tests Upper limb and brachial plexus: pronator quadratus in Anatomy. Pronator teres is supplied higher up by the median nerve itself.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. 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 and brachial plexus: pronator quadratus?

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.