Scanning electron microscopical findings concerning the formation of the Corti organ near the helicotrema in guinea pigs

We report on findings in guinea pigs with objectively tested normal hearing ability. At the apical end of the Corti organ only in the inner row of hai r cells the stereociliae are detectable by scanning electron microscopy. He re the row is interrupted several times. Near the helicotrema we find first the inner row of the outer hair cells, then the middle row and finally the outer row. At the beginning of the D-turn their arrangement is disordered. Normally, at the basal end of the D-turn all rows of inner and outer hair cells show their typical formation. This finding should be taken into consi deration when making a cochleogram for proving of experimental noise damage s.