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Oral Surgery · single question

Which muscle is the PRIMARY muscle that protrudes (protracts) the mandible?

  1. Medial pterygoid
  2. Temporalis
  3. Masseter
  4. Lateral pterygoid (inferior head contracts bilaterally → protrudes mandible)
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Correct answer: D. Lateral pterygoid (inferior head contracts bilaterally → protrudes mandible)

  • A. Medial pterygoid elevates and protrudes (secondary protrusor) but is not the PRIMARY protrusor.
  • B. Temporalis primarily elevates and RETRUDES (posterior fibers) — it opposes protrusion.
  • C. Masseter primarily elevates and slightly protrudes — not the primary protrusor.
  • D. Correct. The LATERAL PTERYGOID (inferior head) is the primary protrusor of the mandible. Bilateral contraction of both lateral pterygoids pulls both condyles anteriorly, protracting the mandible. The superior head is active during jaw CLOSING and disc stabilization.

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