Which cranial nerve is also known as the trigeminal nerve and controls jaw movements?

• A. Facial nerve (CN VII)
• B. Glossopharyngeal nerve (CN IX)
• C. Trigeminal nerve (CN V)
• D. Vagus nerve (CN X)

Answer: (C)

The trigeminal nerve is the one that handles jaw movements because it provides the motor input to the muscles of mastication. Its mandibular division (the motor portion of CN V) innervates the masseter, temporalis, and the medial and lateral pterygoids, allowing biting, chewing, and complex jaw motions. In addition to these motor fibers, CN V also carries sensory information from the face, but the movement of the jaw specifically comes from this nerve’s mandibular branch.

The other nerves listed don’t primarily control jaw movement: the facial nerve mainly innervates facial expression muscles, while the glossopharyngeal and vagus nerves have roles in swallowing, taste, and autonomic functions rather than chewing.