Trismus is due to spasm of which of the following muscle (FMGE Dec 2018): (A) Buccinator, (B) Lateral pterygoid, (C) Medial pterygoid, (D) Mentalis
Answer is C. M - Medial pterygoid - inseed to ramus of mandible from inner side T - Temporalis - inseed into coronoid process of mandible M -Masseter-- inseed to ramus of mandible from outside Lateral pterygoid - depressor of mandible - pull mandible antero-inferiorly and open the mouth Antagonize (MTM muscles) *Tetanus neonatorum - spasm of masseter *Trismus - spasm of muscles of mastication especially medial pterygoid muscle. Mentalis: Deepest muscle of lower group arising from mandible just inferior to incisor teeth, with fibers passing downward & medially to inse into skin of chin. It raises & protrudes lower lip as it wrinkles skin of chin Help position lip when drinking from cup / when pouting Buccinator: Compresses cheek against teeth & is used in acts like blowing