Medial pterygoid muscle

Origin: Deep head: medial side of lateral pterygoid plate behind the upper teeth - superficial head: pyramidal process of palatine bone and maxillary tuberosity

Insertion: Medial angle of the mandible

Artery: Pterygoid branches of maxillary artery

Nerve: Mandibular nerve via nerve to medial pterygoid

Action: Elevates mandible, closes jaw, helps lateral pterygoids in moving the jaw from side to side

Description:
The medial pterygoid is a thick, quadrilateral muscle. It arises from the medial surface of the lateral pterygoid plate and the grooved surface of the pyramidal process of the palatine bone; it has a second slip of origin from the lateral surfaces of the pyramidal process of the palatine and tuberosity of the maxilla. Its fibers pass downward, lateralward, and backward, and are inserted, by a strong tendinous lamina, into the lower and back part of the medial surface of the ramus and angle of the mandible, as high as the mandibular foramen.