[TA] the smaller root of the trigeminal nerve, composed of fibers originating from the trigeminal motor nucleus and emerging from the pons medial to the much larger sensory root, to join the mandibular nerve; it carries motor and proprioceptive fibers to the muscles derived from the first branchial (mandibular) arch (pharyngeal is preferred for humans), including the four muscles of mastication, plus the mylohyoid, anterior belly of the digastric, and the tensores tympani and veli palati. SYN: radix motoria nervi trigemini [TA], masticator nerve, portio minor nervi trigemini.