RESUMO
Objective To research the jugular foramen,internal auditory pore (IAP)and the turning point between its components by imageological methods and to provide theoretical basis for retrosigmoid approach in the operation of acoustic neurinoma.Methods The skulls of 100 volunteers were scanned to get the final result with thin-section computed tomographic image. High-resolution spiral CT multiplane reformation was used to reform images that were parallel to the Frankfort horizontal plane to measure the distance between the turning point of retrosigmoid (A),the edge of jugular foramen(B)and the lower edge of the internal auditory canal(C)(denoted AC,AB,BC) and the shortest distance from the jugular foramen to AC.The angles between AC,AB and sagittal axis(α,β) were measured.Results The distance of AC was (44.94 ± 3.84)mm,the distance of AB was (43.68 ± 4.56)mm.The distance of BC was (6.15 ±2.04)mm,and the shortest distance between jugular foramen and AC was (5.21±0.23)mm.The angleαwas measured as (39.50±4.74)°,and the angleβwas measured as (46.35± 5.51)°.Conclusion The research measure the distance and angle between entry points and landmarks of retrosigmoid approach and the safe distance.