Internal acoustic pathway

The meatus acusticus internus is the internal auditory canal passing through the os temporale. It begins in the porus acusticus internus. Its floor, the fundus meatus acustici interni, is divided into two floors by the crista transversalis. Each floor can be further divided into an anterior and posterior part, in which the fibers of the cranial nerves pass.

Upper floor:


 * front part – area nervi facialis , the facial nerve passes here
 * back part – area vestibularis superior, the utricampullary part of the vestibular nerve passes here

Lower floor:


 * anterior part – tractus spiralis foraminosus for fibers of the cochlear nerve
 * back part - area vestibularis inferior, the saccular part of the vestibular nerve passes through this