Muscles of mastication

The muscles of mastication (Latin: musculi masticatorii) or masticatory muscles are a group of paired muscles responsible for the chewing movements at the temporomandibular joint (TMJ). The masticatory muscles originate from the bones of the skull and insert onto the mandible. These muscles primarily act during mastication. Besides the movements associated with chewing, muscles of mastication also move the lower jaw during speaking. The masticatory muscles help to open and close the mouth.

Masticatory muscles, Muscles of mastication, Temporalis, Masseter, Medial pterygoid, Lateral pterygoid, Head muscles
Masticatory muscles - temporalis (green), masseter (red), lateral pterygoid (blue), medial pterygoid (purple) by Anatomy Next

Each side of the head contains four primary or main muscles of mastication, and they are as follows:

All of these muscles mostly elevate the mandible, except for the lateral pterygoid. Overall, muscles of mastication elevate or depress the mandible, protrude or retract it and cause side-to-side movements of the bone. Unlike the muscles of facial expression that are innervated by the facial nerve (CN VII), the muscles of mastication are innervated by the motor branches of the mandibular division of the trigeminal nerve (CN V3).