Masseter muscle is partly concealed, anteriorly, by the superficial portion. Posteriorly, it is covered by the parotid gland. Along with the other three muscles of mastication (temporalis, medial pterygoid, and lateral pterygoid), the masseter is innervated by the anterior division of the mandibular division (V3) of the trigeminal nerve. The innervation pathway is: gyrus precentralis > genu capsula interna > nucleus motorius nervi trigemini > nervus trigeminus > nervus mandibularis > musculus masseter. The action of the muscle during bilateral contraction of the entire muscle is to elevate the mandible, raising the lower jaw. Elevation of the mandible occurs during the closing
Fascial spaces of the head and neck could therefore be described as a potential space with four separate compartments. Infections usually only occupy one of these compartments, but severe or long standing infections can spread to involve the entire masticator space. The compartments of the masticator space are located on either side of the mandibular ramus and on either side of the temporalis muscle. This is also referred to as the masseter space or the superifical masticator space. The submasseteric space is logically located under (deep to) the masseter muscle, created by the insertions of masseter onto the lateral surface of the mandibular ramus. Submasseteric abscesses are