Bell's palsy: a theory as to etiology. Observations in six patients.

The etiology of Bell's palsy, like a number of other cranial nerve afflictions which consist of rapid or sudden loss of function, has never been satisfactorily explained despite extensive analysis by a number of investigators over the years. These entities may have a simple mechanical explanation in some patients. This consists of the sudden shift of an arterial loop in the cerebellopontine angle stretching the appropriate nerve. In Bell's palsy, the facial-acoustic nerve bundle appears to be stretched and compressed from the anterior aspect. Operative findings showing these abnormalities have been demonstrated in six patients and treated in five. A clinical-pathological analysis of the events of the history and findings in this modest series of patients with Bell's palsy appears to correlate clearly with such a cause.