Which muscles retract the mandible?

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

Answer: (B)

Retracting the mandible is produced by muscles that pull the lower jaw backward. The main driver is the posterior fibers of the temporalis, whose fibers run to the back part of the mandible and pull it toward the ear when the jaw is closed. The deep portion of the masseter also contributes by drawing the ramus backward to seat the mandible in a retruded position, especially when the teeth are in contact and the jaw is stabilized.

The hyoid muscles add to this by stabilizing the mandible–hyoid complex. Through their connections to the mandible and the hyoid bone (notably the posterior digastric and related suprahyoids), they can assist in maintaining or achieving a retruded position during closing.

Protruding and jaw-opening actions are carried by other muscles: the lateral pterygoid mainly protrudes and depresses the mandible, while the medial pterygoid largely elevates and can assist in protrusion. Muscles that open the jaw don’t produce retrusion on their own, so they don’t belong in a retrusion-involved combo.