In CN X role, which statement is true?

• A. Vagus nerve supports voice and swallowing and innervates soft palate muscles; includes sensory and motor roles
• B. Trigeminal nerve is the primary laryngeal nerve
• C. Glossopharyngeal nerve only mediates taste
• D. Olfactory nerve serves velar movement

Answer: (A)

The thing being tested is what the vagus nerve (cranial nerve X) does in the head and neck. The true statement reflects the vagus’s broad role as a mixed nerve with motor, sensory, and parasympathetic functions. It supplies motor control for most muscles of the larynx (crucial for voice) and for many muscles of the soft palate, helping with velopharyngeal closure during speech and swallowing. It also carries sensory information from the larynx and pharynx and provides parasympathetic innervation to much of the thorax and abdomen. Note that the tensor veli palatini, which tenses the soft palate, is innervated by the mandibular division of the trigeminal nerve, not by the vagus, so the statement is accurate about CN X’s involvement with soft palate muscles overall, while recognizing this specific exception.

The other statements misattribute roles: the trigeminal nerve is not the primary laryngeal nerve; the glossopharyngeal nerve carries more than just taste (it has sensory and motor roles in swallowing and other functions); and the olfactory nerve does not control velar movement.