Upper limb and brachial plexus: Bennett fracture: 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: Bennett fracture

Sample item

A boxer punches with a flexed thumb and has pain at the thumb base. A radiograph shows an intra-articular fracture-dislocation of the first metacarpal base with a small volar fragment left in place. Which muscle mainly pulls the metacarpal shaft proximally?

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

The answer and the reasoning

A. Abductor pollicis longus

In a Bennett fracture the small medial (volar) fragment stays attached by the anterior oblique ligament, while the abductor pollicis longus, inserting at the metacarpal base, pulls the shaft proximally and laterally. This instability usually needs fixation.

Option by option

  • A. Abductor pollicis longus (correct)

    Correct. Abductor pollicis longus inserts at the metacarpal base and displaces the shaft proximally.

  • B. Extensor pollicis longus

    Extensor pollicis longus inserts on the distal phalanx and does not pull the base.

  • C. Flexor pollicis brevis

    Flexor pollicis brevis inserts on the proximal phalanx and does not displace the metacarpal.

  • D. Flexor pollicis longus

    Flexor pollicis longus inserts on the distal phalanx and does not act on the metacarpal base.

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, Abductor pollicis longus. In a Bennett fracture the small medial (volar) fragment stays attached by the anterior oblique ligament, while the abductor pollicis longus, inserting at the metacarpal base, pulls the shaft proximally and laterally.

Why is "Extensor pollicis longus" not the answer?

Extensor pollicis longus inserts on the distal phalanx and does not pull the base.

Why is "Flexor pollicis brevis" not the answer?

Flexor pollicis brevis inserts on the proximal phalanx and does not displace the metacarpal.

Why is "Flexor pollicis longus" not the answer?

Flexor pollicis longus inserts on the distal phalanx and does not act on the metacarpal base.

What concept does this question test?

It tests Upper limb and brachial plexus: Bennett fracture in Anatomy. This instability usually needs fixation.

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: Bennett fracture?

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.