The facial canal: normal anatomy, variations and anomalies. I. Normal anatomy of the facial canal.

Modern otologic surgery revolves around the use of the operating microscope. The surgeon must have a thorough knowledge of all structures in the temporal bone, particularly since surgery may now be directed to areas in its deeper portions. Of concern here is the whereabouts of the facial canal in its complex course through the temporal bone. A detailed descriptive anatomy with emphasis on the relations of the facial canal to adjacent structures is presented. The variations in the course of the facial canal are discussed. The location of dehiscences in the bony canal wall are described. Finally, great stress is laid upon presentation of these anomalies known to us which can occur in the course of the facial nerve through the temporal bone. These anomalies have clinical and surgical significance.