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
Muscle fatigue reticulum. Fatigue (reduced ability to generate force) may occur due to the nerve, or within the muscle cells themselves. Nerves are responsible for controlling the contraction of muscles, determining the number, sequence and force of muscular contraction. Most movements require a force far below what a muscle could potentially generate, and barring pathological nervous fatigue, is seldom an issue. But in extremely powerful contractions that are close to the upper limit of a muscle's ability to generate force, nervous fatigue (enervation), in which the nerve signal weakens, can be a limiting factor in untrained individuals. In novice strength trainers, the