Anatomy & Histology · patient case question
The fibres of which muscle retrude the mandible?
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: D. The posterior fibres of temporalis
- A. The inferior head of lateral pterygoid protrudes the mandible, which is the opposite movement.
- B. The anterior temporalis fibres are near vertical and elevate the mandible.
- C. The superficial masseter fibres run downward and backward, so they elevate and slightly protrude.
- D. Correct. The posterior fibres of temporalis run almost horizontally forward to the coronoid process, so their line of pull draws the mandible backward. They are assisted in retrusion by the deep masseter fibres and the digastric.
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