Last revised by Raymond Chieng on 30 May 2023

Perilymph is one of the two types of fluid in the inner ear, the other being endolymph. It surrounds the membranous labyrinth within the bony labyrinth. The portion within the cochlea is located in the scala vestibuli and scala tympani.

It is a clear fluid with an ionic composition very similar to cerebrospinal fluid as the scala vestibuli and scala tympani communicate directly with the subarachnoid space via the perilymphatic duct (within the cochlear aqueduct). It has a high level of sodium (Na+) ions and helps to generate the endolymphatic potential.

The endolymph and perilymph do not normally communicate.

Radiographic features


Gadolinium administration accumulates within the perilymph of the cochlea while leaving the endolymph unenhanced 3. This is because the blood-perilymph barrier is permeable to gadolinium while blood-endolymph and perilymph-endolymph barriers are impermeable to gadolinium 4.

See also

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