The mandibular division provides motor innervation to which group of muscles?

• A. Intrinsic eye muscles
• B. Muscles of mastication
• C. Muscles of facial expression
• D. Pharyngeal constrictors

Answer: (B)

Motor innervation from the mandibular division of the trigeminal nerve goes to the muscles responsible for chewing. These muscles—the masseter, temporalis, and the medial and lateral pterygoids—are derived from the first pharyngeal arch and are specifically supplied by V3. This division also carries motor fibers to related jaw-opening muscles like the anterior belly of the digastric and the mylohyoid, but the group you’re being asked about is the muscles of mastication. Other muscle groups mentioned are controlled by different nerves: intrinsic eye muscles by the oculomotor nerve, facial expression muscles by the facial nerve, and pharyngeal constrictors by branches of the vagus (and related nerves) rather than V3.