Opening of the jaw is done by the:

Ans: b (Lateral pterygoid) Ref.: BDC, 4th ed, VoL III, p. 152Depressing the jaw, ie. opening wide of the mouth is brought about mainly by the lateral pterygoid. The muscles which assist are the digastric, geniohyoid and mylohyoid.Movements that occur at the temporo-mandibular joint and muscles responsible:MOVEMENTMUSCLESDepressionLateral pterygoidElevationMasseter, temporalis, Medial pterygoidProtrusionLateral and medial pterygoidsRetractionTemporalis (posterior fibres)Lateral movementsTo the left: Lt. Lateral PterygoidRt. Medial Pterygoid To the right: Rt. Lateral PterygoidLt. Medial Pterygoid