The hypoglossal nerve is the twelfth cranial nerve and controls movement of the tongue. The path of the nerve starts in the hypoglossal nucleus of the brainstem, and then travels between the carotid artery and jugular vein to end up under the tongue. If there are problems with the hypoglossal nerve, the tongue may be paralyzed. To test the function, the patient would be asked to stick out their tongue. If paralysis were present, the tongue would point in the direction of the affected side. Another test monitors the strength of the tongue by having the patient press their tongue against the side of their cheek. The doctor can then tell how strongly the patient is pressing. Eventually, the tongue will begin to atrophy, or shrink, if the hypoglossal nerve is permanently damaged. The hypoglossal nerve may be impacted by several things, such as tumors at the base of the skull, strokes, infections, or neck injuries. Any of these can lead to a problem with speaking, chewing, or swallowing. Once the cause is determined the doctor can look for suitable treatments to restore functionality to the nerve.
Written and medically reviewed by the Healthline Editorial Team
In Depth: Hypoglossal nerve