Which cranial nerve is responsible for motor function of the tongue?

The hypoglossal nerve, also known as cranial nerve XII, is primarily responsible for the motor function of the tongue. This nerve innervates most of the intrinsic and extrinsic muscles of the tongue, enabling movements that are crucial for actions such as swallowing, speaking, and manipulating food within the mouth.

The intrinsic muscles of the tongue, which change its shape, and the extrinsic muscles, which help in the positioning and movement of the tongue within the oral cavity, are all controlled by the hypoglossal nerve. This motor function allows for the precision movements required for articulating speech and performing other functions involving the tongue.

The other cranial nerves mentioned have different roles. The trigeminal nerve (CN V) is primarily responsible for sensation in the face and motor functions such as chewing, while the facial nerve (CN VII) mainly controls the muscles of facial expression and carries taste sensations from the anterior two-thirds of the tongue. The vagus nerve (CN X) is involved in autonomic functions and some sensory and motor control of the throat and larynx, rather than the motor control of the tongue itself. Therefore, the hypoglossal nerve is unequivocally the key player in the motor control of the tongue