Objectives : The aim of this study was to investigate the anatomical relation of cochlea and surrounding structures and to be a help to preserve its function.
Materials and Method : We dissected 10 fresh temporal bones of Korean adults under surgical microscope and measured distances and angle between cochlea and its surrounding structures including Bill's bar. Temporal bones with post-operative ear, anomaly, malignant metastatic tumor, bone disease, and severe inflammation were excluded.
Results : We made imaginary point on the anterior border of internal auditory canal (point A). Point A was located 7.46±0.26㎜ from the anterior border of Bill's bar and cochlea was located within angle of 30.3±0.81 degree from the line connecting anterior border of Bill's bar and point A. Internal carotid artery was located 6.53±0.30㎜ from the point A. With these findings, We could safely dissect medial area to the line connecting internal carotid artery and point A. We made selected vertical sections stained in hematoxylin-eosin to evaluated the depth of cochlea from the middle cranial fossa and the depth was 2.45±0.05㎜.
Conclusion : We could suggest the anatomical landmarks for preservation of cochlea in performing petrosal approach.