The medial pterygoid muscle is one of the four muscles of mastication (chewing). It is thick and rectangular in shape. It is located in the posterior and lower part of the human face. The medial pterygoid is made up of two heads; one head of the muscle arises from the walls of the pterygoid fossa of sphenoid bone, while the other originates from the tuberosity of maxilla. Then its fibers converge into one muscle which runs downwards and obliquely backwards to be inserted into the postero-medial surface of mandible.
Action/Function
This thick muscle of mastication displaces the mandible to the contralateral (opposite) side. Its bilateral contraction raises the lower jaw and causes forward protrusion mandible.
Innervation
The medial pterygoid muscle is innervated by a branch of the trigeminal nerve (CN V).
Blood Supply
This muscle receives oxygenated blood from branches of the inferior alveolar (which arises from maxillary artery), the buccal, and facial artery (which springs from the external carotid).
Below, drawing of the human skull showing the medial pterygoid, the lateral pterygoid, and the temporalis muscle. The masseter and the zygomatic arch are missing.
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