Hypoglossal Nerve

The hypoglossal nerve is motor to the tongue.

Examination Technique:

• observe for tongue atrophy or enlargement.
• do not overcall tongue fasciculations. It is very difficult to relax the tongue.
• ask the patient to protrude the tongue.
• ask the patient to push the tongue into each cheek or alternatively to protrude the tongue and push it laterally against a tongue depressor.
• ask the patient to move the tongue quickly from side to side.
• if there is facial weakness, correct this by supporting the upper lip on the side of weakness, otherwise there may appear to be deviation of the tongue but once the facial weakness is corrected for, the tongue will no longer appear to deviate.

Normal Response:
the tongue should be able to protrude relatively straight. Minimal degrees of deviation (i.e. only millimeters) affecting only the tip are insignificant.

Abnormal Response:
with tongue weakness, the tongue deviates towards the weak side.