Patterns of degeneration of the facial nerve.

Facial palsy is a distressing nonfatal disorder that creates an emotional crisis for the patient and often a therapeutic enigma for the physician. Among the causes for facial palsy are neoplasia, infection, trauma, and dysmorphogenesis. Histologic studies of the temporal bones of twelve subjects with facial nerve pathology demonstrate the susceptibility of the nerve to pressure atrophy in its course in the temporal bone. Lesions located central to the genu cause degeneration of the motor component distally and the sensory component medially. Lesions located peripheral to the genu cause degeneration of both sensory and motor bundles distally.