Cranial nerve XII, also known as the hypoglossal nerve, is one of the twelve pairs of cranial nerves that originate from the brainstem. It is responsible for the voluntary movement of the muscles that control the tongue, known as the intrinsic and extrinsic muscles.
The cranial nerve XII emerges from the medulla oblongata, the lower part of the brainstem, and descends through the neck and into the tongue. Its primary role is to innervate the muscles that facilitate speech, swallowing, and chewing, as well as providing sensory information from these muscles to the brain.
Damage or dysfunction of the hypoglossal nerve can result in various symptoms such as difficultly moving the tongue, atrophy or wasting of the tongue muscles, slurred speech, impaired swallowing, and difficulty protruding or retracting the tongue. This can be caused by trauma, stroke, infections, tumors, or any other condition that affects the nerve fibers of cranial nerve XII.
The hypoglossal nerve is typically examined during a neurological examination by assessing the movement and strength of the tongue and observing any deviations from normal function. Treatment options for cranial nerve XII dysfunction depend on the underlying cause and may include speech therapy, medication, surgery, or other interventions aimed at restoring proper nerve function.
