Bilateral injury to the hypoglossal nerve.

The hypoglossal nerve supplies motor function to the tongue. Two cases of bilateral, post-traumatic injury to the hypoglossal nerve are described. Physical and electromyographic examinations in these cases showed evidence of bilateral injury to the hypoglossal nerve as well as the absence of injury to the other closely associated cranial nerves. (A review of the English literature in the past 20 years shows no cases of isolated bilateral damage to the hypoglossal nerve, although there are several cases of unilateral or combined injury.) The disabilities resulting from hypoglossal nerve palsy and the importance of the tongue in normal swallowing are discussed. Two possible causes of hypoglossal nerve palsy are offered.