[TA] a group of motor neurons innervating the muscles of mastication (masseter, temporalis, and internal and external pterygoid muscles) and the musculi tensor tympani and tensor veli palatini. The nucleus lies in the upper pontine tegmentum medial to the principal sensory nucleus of the trigeminal nerve. SYN: nucleus motorius nervi trigemini [TA], masticatory nucleus, motor nucleus of trigeminus, nucleus masticatorius.