Three-Dimensional Reconstruction of the Human Semicircular Canals and Measurement of Each Membranous Canal Plane Defined by Reid's Stereotactic Coordinates

Abstract

Objectives: Equations for estimating the planar relationships of the human semicircular canals were devised by Blanks et al from a dissected bony labyrinth in a human skull. However, a similar study on the membranous semicircular canal planes has never been published. Methods: In this study, the angle between each membranous canal plane and Reid's stereotactic horizontal plane was measured on serial histologic sections of 7 temporal bones from Japanese adults. We reconstructed the 3 semicircular canals by computer-aided 3-dimensional analysis. The angles between each pair of both bony and membranous canal planes were measured. Results: In the bony labyrinth, the angles between the 2 canal planes of the lateral-anterior, anterior-posterior, and lateral-posterior pairs were 90.51° ± 2.98° (mean ± SD), 91.70° ± 1.85°, and 94.52° ± 3.32°, respectively. The angles between the 2 membranous canal planes of the lateral-anterior, anterior-posterior, and lateral-posterior pairs were 90.05° ± 4.74°, 91.03° ± 2.93°, and 91.92° ± 5.22°, respectively. Conclusions: The data from our study of the membranous labyrinth showed that the angles between each canal plane and the others were much closer to 90° than was found by Blanks et al for the bony labyrinth.