Which branch of the trigeminal nerve is both motor and sensory?

• A. CN V1 (Ophthalmic)
• B. CN V2 (Maxillary)
• C. CN V3 (Mandibular)
• D. CN X (Vagus)

Answer: (C)

The branch that is both motor and sensory is the mandibular division. It carries motor fibers that innervate the muscles of mastication (masseter, temporalis, and the medial and lateral pterygoids) as well as other first-arch muscles like tensor tympani, tensor veli palatini, and the anterior belly of the digastric and mylohyoid. It also provides sensation from the lower face and jaw region, including the skin of the lower lip and chin, lower teeth and gums, floor of the mouth, and parts of the tongue for general sensation. The other trigeminal divisions are purely sensory, supplying the forehead and scalp (V1) and the midface and upper teeth (V2), while the vagus nerve (different cranial nerve) is not part of the trigeminal system.