Which cranial nerve is associated with tongue movement?

• A. CN XII
• B. CN III
• C. CN VII
• D. CN X

Answer: (A)

Tongue movement is controlled by the hypoglossal nerve, cranial nerve XII. It provides motor input to all intrinsic tongue muscles that shape the tongue and to most extrinsic muscles that move it—such as protrusion (genioglossus), retraction (styloglossus), and depression (hyoglossus). The one exception is palatoglossus, which is innervated by the vagus nerve (cranial nerve X). If cranial nerve XII is damaged, the tongue tends to deviate toward the side of the lesion when asked to protrude, due to weakness on that side. The other nerves listed have different roles: one mainly moves the eyes, one controls facial muscles (and some taste), and one controls the palate, pharynx, and autonomic functions. That makes cranial nerve XII the one most directly responsible for tongue movement.