Pathology · single question
Which muscle is LEAST affected by bruxism?
Show answer and explanation
Correct answer: D. Buccinator
The buccinator is a cheek muscle involved in chewing/facial expression but NOT a primary muscle of mastication. Bruxism primarily affects the muscles of mastication: masseter, temporalis, and medial pterygoid. The lateral pterygoid is involved in jaw protrusion and TMJ function, often affected in parafunctional habits. Buccinator is least involved.
- A. ❌ The temporalis is heavily involved — its posterior fibers retrude the mandible, and temporalis tenderness produces the characteristic temporal headache.
- B. ❌ The lateral pterygoid protrudes the mandible and is commonly involved in the excursive component of grinding.
- C. ✅ CORRECT — The BUCCINATOR is a muscle of FACIAL EXPRESSION (facial nerve, VII). It compresses the cheek and keeps the food bolus on the occlusal table; it plays no role in elevating the mandible or generating occlusal force, so it is not loaded by parafunction.
- D. ❌ The masseter is the primary elevator and the muscle most commonly hypertrophied and tender in bruxers.
Note: Muscles of MASTICATION (V3): masseter, temporalis, medial and lateral pterygoid. Buccinator is facial expression (VII) despite its position.