Computer-aided three-dimensional reconstruction and measurement of semicircular canals and their cristae in man.

We studied the spatial relations of the semicircular canals (SCCs) and their cristae, by computer-aided three-dimensional reconstruction, a graphic method we developed. The angles between pairs of SCCs, between pairs of SCC cristae, and between a SCC and its crista were measured using histology sections of a normal temporal bone from a 14-year-old female. Angles between pairs of SCCs and pairs of cristae deviated 11.3 to 18.2 degrees and 4.8 to 18.0 degrees, respectively, from right angles and the long axis of each crista deviated 25.0 to 30.4 degrees from the line perpendicular to the plane of the corresponding SCC; thus none of these structures lies at a right angle to another. We believe these new anatomical findings will help in the clinical evaluation of SCC function.