Medial pterygoid

The medial pterygoid (Latin: musculus pterygoideus medialis) is a thick and quadrilateral-shaped muscle located in the infratemporal fossa of the skull. It is classified as one of the primary muscles of mastication. The medial pterygoid is composed of two heads - superficial (smaller) and deep (larger). This muscle provides movements of the mandible at the temporomandibular joint (TMJ).

Origin

The superficial head of the medial pterygoid muscle originates from the maxillary tuberosity of the maxilla and pyramidal process of the palatine bone. The deep head of the muscle originates from the medial surface of the lateral pterygoid plate (of the sphenoid bone).

Insertion

The medial pterygoid inserts on the pterygoid tuberosity of the mandible and medial (inner) surface of the mandibular ramus.

Action

Upon bilateral contractions, the medial pterygoid muscles push the mandible forward (protrude the mandible). By contracting on one side, the medial pterygoid pushes the mandible to the opposite side. This muscle also contributes to the elevation of the mandible, acting as a synergist to the temporalis and masseter.

Innervation

The medial pterygoid muscle is innervated by the medial pterygoid nerve, a branch of the mandibular division of the trigeminal nerve (CN V3).

Blood supply

The medial pterygoid is provided with the arterial blood supply by the pterygoid branches arising from the maxillary, buccal (branch of the maxillary artery) and facial arteries.