Innervation
Along with the other three muscles of mastication (temporalis, medial pterygoid and lateral pterygoid), the masseter is innervated by 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.
Read more about this topic: Masseter Muscle