Anatomy & Histology · single question
A mandibular fracture involves the ramus. Which muscle would normally assist in OPENING the jaw?
Show answer and explanation
Correct answer: A. Lateral pterygoid
- A. CORRECT. The INFERIOR head of the LATERAL PTERYGOID is the only muscle of mastication that DEPRESSES the mandible. It pulls the condyle and disc forward and downward along the articular eminence — translation, which combined with the digastric/suprahyoid group produces opening. In a ramus or condylar fracture, its unopposed pull typically displaces the proximal segment anteromedially.
- B. The temporalis ELEVATES and, via its posterior fibres, retrudes the mandible.
- C. The medial pterygoid is an ELEVATOR (it forms a sling with the masseter). It closes the jaw and assists protrusion.
- D. The masseter is the most powerful ELEVATOR, closing the jaw.
Note: Memory hook: of the four muscles of mastication, only the lateral pterygoid opens. Everything else closes.
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