pterygoideus

Pterygoideus is a Latin term used in anatomy to indicate a relation to the pterygoid processes of the sphenoid bone, or to muscles bearing the name pterygoideus. In human anatomy, the most common reference is to the pair of muscles of mastication known as the medial and lateral pterygoid muscles (musculus pterygoideus medialis and musculus pterygoideus lateralis). Both muscles are innervated by the mandibular division (V3) of the trigeminal nerve, and they work together with other masticatory muscles to facilitate jaw movements.

Medial pterygoid: The muscle has two heads. The deep head originates from the pterygoid fossa on the sphenoid bone, and the superficial head from the tuberosity of the maxilla. It inserts on the medial surface of the mandible near the angle. Its primary actions are elevation of the mandible (closing the jaw) and, with other muscles, assistance in protrusion and grinding movements. It is supplied by the nerve to the medial pterygoid, a branch of V3, with vascular input from pterygoid branches of the maxillary artery.

Lateral pterygoid: This muscle also has two heads. The superior head originates from the infratemporal surface of the greater wing of the sphenoid, and the inferior head from the lateral surface of the lateral pterygoid plate. It inserts into the pterygoid fovea on the neck of the mandible and, via the articular disc and TMJ capsule, contributes to jaw movement. Its primary actions are protrusion of the mandible and, during unilateral contraction, guiding lateral movement of the jaw. Innervation is by the nerve to the lateral pterygoid (V3), and arterial supply comes from the pterygoid branches of the maxillary artery.

Clinically, these muscles are key components of mastication and can be involved in temporomandibular disorders, jaw opening functions, and bite mechanics.