Histology of the cochlear vessels in the guinea pig.

Normal adult guinea pigs were studied in phase contrast microscopy. Perivascular spaces were clearly more common in vessels facing perilymph than in vessels facing endolymph. The so-called "avascular channels" which have been suggested to signify a degenerative phenomenon were found in some inner ear vessels in the normal animal. These sections of vessels, lacking blood cells, may constitute a normal vessel, subjected to plasma skimming. Small openings were found on some of these "avascular channels". Both perivascular spaces and "avascular channels" appear to be a part of the fluid transport system in the cochlea.