Multidirectional tomography of the facial canal.

The course of the facial canal in the complicated structure of the temporal bone is best demonstrated by multidirectional (hypocycloid or spiral) tomography. A description of its normal anatomy is delivered, based on experiences from dissected temporal bone specimens, plastic moulds and tomograms. Detailed knowledge of the anatomy is required for distinction of defects and anomalies, particularly pre-operatively (fractures, reconstructive middle ear surgery). In malformation the pre-operative localization of the course of the facial canal is important, since its relation to the oval window and the posterior wall of the tympanic cavity is decisive for surgical procedures.