Comparative anatomy of cochlear blood vessels.

The vascular anatomy of most mammalian cochleas is similar. Of those examined to date, the human cochlea is the most unusual. The blood flow is segmentally, centrifugally, and centripetally arranged, with many spirally perpendicular vessels shunted in, suggesting good possibilities for variations of circulation. There is a pronounced apical simplification of the vascular pattern probably more than corresponding to the decreasing volume of the turns. The blood supply of the scala vestibuli is mainly arterial; that of the scala media is capillary or by-pass, and that of the scala tympani is venous. The vessel of the basilar membrane shows great variations among species, from presence in all turns to complete non-existence. Its importance and size is greater during embryonic life.