For retraction of the mandible, which muscles are involved?

• A. Masseter and lateral pterygoid
• B. Medial pterygoid only
• C. Lateral pterygoid only
• D. Temporalis (posterior), masseter, hyoids

Answer: (D)

Retraction of the mandible is achieved by muscles that pull the lower jaw backward toward the temporal fossa, with a stable base to allow that backward movement. The posterior fibers of the temporalis are the primary drivers here because they attach to the coronoid process and pull the mandible back when they contract, drawing the jaw into a retruded position. The masseter contributes as well, especially its deep portion, which has a backward-directed vector on the ramus that supports retraction during closure. The hyoid muscles provide essential stabilization of the jaw–hyoid complex; by anchoring the hyoid bone, they allow the posterior pull from temporalis and masseter to move the mandible smoothly without destabilizing surrounding structures. In contrast, muscles like the lateral pterygoid promote protrusion and opening, opposing retrusion, so they’re not the primary movers for drawing the mandible back.