Head and Neck Anatomical Structures · USMLE Step 1

A patient has difficulty opening the mouth after a mandibular fracture. Which muscle is primarily responsible for depressing the mandible?

  1. Masseter
  2. Lateral pterygoid
  3. Temporalis
  4. Medial pterygoid
Show answer and explanation

Correct answer: Lateral pterygoid

The lateral pterygoid opens the jaw by protruding and depressing the mandible. It is the only major muscle of mastication that opens the mouth.

Difficulty: Medium Question 15 of 20

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