Perilymphatic communication routes in the auditory and vestibular system.

Horseradish peroxidase was injected into the foramen magnum and oval window of guinea pigs to determine perilymphatic communication routes and boundaries. The primary route to the auditory system appeared to be through the cochlear aqueduct. Perineural spaces of the eighth nerve contributed to this communication and provided the principal perilymphatic communication routes to the vestibular system. Light and electron microscopic examination were used to identify membrane permeability and define boundaries in the epithelial lining of the auditory and vestibular endorgans.