pterygoidei

Pterygoidei is the collective term for the pterygoid muscles, the medial pterygoid and the lateral pterygoid, which are paired muscles of mastication located in the infratemporal fossa. They function together with other masticatory muscles to move the mandible during chewing and speech.

The medial pterygoid originates from the medial surface of the lateral pterygoid plate (pterygoid fossa), the pyramidal process of the palatine bone, and the tuberosity of the maxilla. It inserts on the medial surface of the mandible near the angle and ramus. The lateral pterygoid has two heads: a superior head from the infratemporal surface of the greater wing of the sphenoid and an inferior head from the lateral pterygoid plate. It inserts into the articular disc and the neck of the mandible at the pterygoid fovea.

Innervation of the pterygoidei is provided by branches of the mandibular division of the trigeminal nerve (V3): the nerve to the medial pterygoid and the nerve to the lateral pterygoid. Blood supply is from branches of the maxillary artery, with venous drainage into the pterygoid plexus.

Actions include bilateral and unilateral movements. The medial pterygoid elevates the mandible, aiding in jaw closure, while the lateral pterygoid protrudes the mandible and assists in opening the jaw; the superior head also helps stabilize the articular disc during movement. Unilateral contraction produces grinding and side-to-side movements. Together, the pterygoidei contribute to complex chewing mechanics and TMJ function.