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What is the function of lateral pterygoid muscle?

asked Apr 4, 2017 in Anatomy by Rajesh Bahara
A 34-year-old man injures his lateral pterygoid muscle. Which of the following activities will be adversely affected by this injury?
(A) Closing the jaw
(B) Smiling
(C) Swallowing
(D) Whistling
(E) Yawning

1 Answer

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Best answer
(E) Yawning
The muscles involved in jaw movement are fourfold: lateral pterygoid, masseter, temporalis, and medial pterygoid. The lateral pterygoid opens the jaw while the other three close the jaw. All four are innervated by the trigeminal nerve (V3). One can remember this with the mnemonic “M’s Munch” and “Lateral Lowers.” Yawning would be impaired with a lateral pterygoid injury.

Answer A is incorrect. Closing the mouth is performed by the masseter, temporalis, and medial pterygoid.
Answer B is incorrect. Smiling requires the function of many facial muscles, including the zygomaticus major.
Answer C is incorrect. Swallowing is mediated by the pharynx and the tongue.
Answer D is incorrect. Whistling is mediated by the tongue and facial muscles, such as the buccinator and orbicularis oris.
answered Apr 4, 2017 by Rajesh Bahara

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