Abstract: Objective · To study how to localize the internal auditory canal in the middle cranial fossa approach in Chinese using CT reconstruction technique. Methods · Forty-four cases (88 sides) of normal temporal bone CT data were selected, including 22 males and 22 females. The anatomical structures of the middle cranial fossa including the skull base, the internal auditory canal and the superior semicircular canal were reconstructed in 3D. The angle between great superficial petrosal nerve and internal auditory canal, the angle between superior semicircular canal and internal auditory canal and the osseous thickness above internal auditory canal were measured. The angle and distance were statistically analyzed in different sex and side groups. Results · On the reconstructed 3D middle cranial base, the arcuate eminence could only be identified in 43% cases. The angle between great superficial petrosal nerve and internal auditory canal was 51.46.±9.28.; the angle between superior semicircular canal and internal auditory canal was 49.22.±7.32.; the osseous thickness above internal auditory canal was (4.38±0.97) mm. No gender or side difference was noticed. Conclusion · There are significant individual differences in angulation and distance between the internal auditory canal and its related anatomical structures. CT reconstruction technique is helpful for accurate localization of the internal auditory canal.

Key words: internal auditory canal, middle cranial fossa approach, skull base anatomy, computed tomography