The cochlea and the carotid canal.

The carotid canal conveys a large artery and lies in close topographic relationship to the basal turn of the cochlea. The bony wall between them consists in some cases only of the petrous bone of the otic capsule. It can be as thin as 0.2 mm. In other cases the distance can be more than 6 mm. A systematic assessment of the relationship between these two structures was performed on plastic casts of 173 human temporal bone specimens in order to investigate the range of normal variation. The topography in this region can be visualized by multidirectional tomography or CT.