Abstract
The Perilymphatic and cerebrospinal fluid (CSF) pressures were measured in normal cats, cats with obstructed cochlear aqueduct and cats with obstructed cochlear aqueduct and endolymphatic duct. There was no difference in the mean value of the perilymphatic pressure in the 3 groups of animals. The perilymphatic and CSF pressures correlated in the first 2 groups, but not after obstruction of both ducts. The physiological respiratory and pulsatory variations of the perilymphatic pressure are present in all investigated groups of animals. However, the obstruction of the cochlear aqueduct remarkably reduces the transmission of artificially elevated CSF pressures to the perilymph. This indicates that there is a limit for the transmission of variations of the CSF pressure through the endolymphatic sac system. Therefore, the question whether the cochlear aqueduct and the endolymphatic sac system may equalize the pressures of the perilymph and endolymph in presence of abnormal variations of the CSF pressure still remains open.
