The masticatory muscles (or muscles of mastication) are responsible for the chewing movements of the mandible or lower jaw. The masticatory muscles originate on the skull and insert onto the mandible, thus acting upon the mastication and other movements of the lower jaw at the temporomandibular joint.
There are four masticatory muscles on each side of the head:
- lateral pterygoid,
- medial pterygoid.
Unlike the muscles of facial expression that are innervated by the facial nerve (CN VII), the muscles of mastication are innervated by motor branches of the mandibular division of the trigeminal nerve (CN V3).