Deviant facial nerve course in the middle ear cavity.

Anomalous facial nerve (FN) course can be found in a significant number of cases with aural anomalies. The most common anomaly of the FN involves the tympanic portion overlying the oval window.1--3 Facial canal dehiscence of the tympanic portion may be responsible for the anomalous course of FN over the oval window. The incidence of facial canal dehiscence found during otologic surgery is relatively frequent and is usually related with cholesteatomas.4,5 Aberrant FN course in a patient without accompanying anomaly or cholesteatoma has been demonstrated in a previous case report.6 However, the patient had not undergone imaging evaluation. Herein, the authors report an abnormal FN course in the tympanic portion, without any other associated anomalies.