CASE 13 — Patient presents with masticatory muscle spasm. Which muscle is most commonly affected?

Correct answer: B. Masseter

• A. The buccinator is a cheek muscle primarily involved in keeping food on the occlusal table; not typically a site of TMD-related spasm.
• B. The masseter is the most commonly affected muscle in masticatory muscle disorders (myofascial pain, myalgia, spasm). It is easily palpable extraorally and frequently exhibits tenderness and hyperactivity in bruxism and TMD.
• C. The temporalis is frequently involved in tension-type headaches and TMD but the masseter is cited as the most common site.
• D. The lateral pterygoid is involved in TMD (disc displacement) but is not the most commonly reported site of palpable spasm.