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
Lateral force transmission in skeletal muscle and reorientation of the perimysium makes it much stiffer and able to transmit tensile force. Scanning electron microscope images have shown that the perimysium has an organized crimped structure. The crimped structure of the perimysium makes it very compliant in tension under normal physiological conditions allowing the muscle to change shape, thus rendering it unfeasible for tensile force transmission. Although strong efforts have been made to demonstrate the mechanical role of the perimysium as a force transmission pathway during active contraction of the muscle, an accepted model has yet to be derived. It can also be suggested that the perimysium