Which cranial nerve is NOT involved in motor function to the tongue?

The glossopharyngeal nerve, trigeminal nerve, hypoglossal nerve, and spinal accessory nerve all have distinct roles when it comes to movement and sensation in the head and neck regions, particularly in relation to the tongue.

The hypoglossal nerve specifically controls the motor function of most of the intrinsic and extrinsic muscles of the tongue. This makes it a primary nerve responsible for movements of the tongue, particularly important for actions such as speaking and swallowing.

The glossopharyngeal nerve has some minor contributions to motor function, primarily associated with the stylopharyngeus muscle, which is involved in swallowing rather than tongue movement. It plays a more significant role in taste and sensation for the posterior third of the tongue.

The spinal accessory nerve primarily innervates muscles involved in head movement, such as the sternocleidomastoid and trapezius, and it does not contribute to tongue movement.

The trigeminal nerve is primarily associated with sensory functions for the face but it also contains a motor component that controls mastication through muscles such as the masseter and temporalis. However, it does not control the movements of the tongue itself.

Therefore, the trigeminal nerve is not involved in motor function to the