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

The cranial nerve that is primarily responsible for the motor function of the tongue is the Hypoglossal nerve, which is cranial nerve XII. This nerve innervates most of the muscles of the tongue, facilitating movements necessary for speech, swallowing, and food manipulation. It precisely controls the action of the intrinsic and extrinsic muscles of the tongue, allowing for intricate movements such as protrusion, retraction, and lateralization.

While other cranial nerves, such as the Glossopharyngeal and Vagus nerves, play roles in swallowing and taste sensation, they do not primarily govern the motor movements of the tongue itself. Therefore, their involvement is more related to different functions such as sensory input or autonomic regulation rather than direct control of tongue movement. The Spinal Accessory nerve mainly innervates neck muscles and does not contribute to tongue motor function.