Head and neck: lateral pterygoid muscle: 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 · Head and neck: lateral pterygoid muscle

Sample item

A patient has an isolated weakness of one muscle of mastication. When she opens her mouth wide, her jaw deviates to the right. Which muscle is weak?

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

The answer and the reasoning

B. Right lateral pterygoid

The lateral pterygoids pull the head of the mandible forward and downward on opening. If one is weak, the opposite side protrudes unopposed and the jaw deviates toward the weak side. Elevators such as masseter and temporalis act on closing.

Option by option

  • A. Right masseter

    The masseter is an elevator and its weakness affects closing and clenching.

  • B. Right lateral pterygoid (correct)

    Correct. Weakness of the right lateral pterygoid deviates the jaw to the right on opening.

  • C. Left temporalis

    Temporalis is an elevator and retractor and does not control deviation on opening.

  • D. Left lateral pterygoid

    A weak left lateral pterygoid would deviate the jaw to the left.

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 B, Right lateral pterygoid. The lateral pterygoids pull the head of the mandible forward and downward on opening.

Why is "Right masseter" not the answer?

The masseter is an elevator and its weakness affects closing and clenching.

Why is "Left temporalis" not the answer?

Temporalis is an elevator and retractor and does not control deviation on opening.

Why is "Left lateral pterygoid" not the answer?

A weak left lateral pterygoid would deviate the jaw to the left.

What concept does this question test?

It tests Head and neck: lateral pterygoid muscle in Anatomy. If one is weak, the opposite side protrudes unopposed and the jaw deviates toward the weak side. Elevators such as masseter and temporalis act on closing.

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 Head and neck: lateral pterygoid muscle?

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.