Anatomy & Histology · patient case question
All of the following are muscles of mandibular closure EXCEPT:
Patient case: Muscles, movement and a fractured condyle
demo: 29-year-old male
chief: Fell from a bicycle onto his chin; his bite now feels wrong.
history: No relevant medical history.
meds: None.
findings: Deviation of the mandible on opening, an anterior open bite and preauricular tenderness. Imaging confirms a fracture of the condylar neck with the condylar head displaced out of the fossa.
Show answer and explanation
Correct answer: A. Lateral pterygoid
- A. Correct, and this is the exception. The inferior head of the lateral pterygoid is the principal muscle of opening, protruding the mandible and pulling the condyle and disc forward down the articular eminence. Its superior head stabilises the disc during closure but the muscle as a whole is not a closer.
- B. The masseter is a powerful elevator and the strongest muscle of mastication by force per cross-sectional area.
- C. The medial pterygoid elevates the mandible, working with the masseter as a functional sling around the angle.
- D. Temporalis elevates the mandible, and its posterior fibres retrude it.
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