The repair pattern of the reticular lamina of the organ of Corti was studied in the cochleae of human ears. The inner ears were obtained at autopsy from the individuals who had no evidence of auditory or vestibular disorders or therapy with ototoxic drugs.
1) After a loss of outer or inner hair cells, the framework of the reticular lamina was distorted, but no gaps were detected. The supporting cells were hypertrophied, but no reparative proliferation of the supporting cells were found in the organ of Corti.
2) Defects due to the collapse of outer hair cells of the first row were replaced mainly by the hypertrophied heads of the outer pillar cells.
3) Defects due to the collapse of outer hair cells of the second, third, and fourth row were replaced mainly by the hypertrophied phalanges of Deiters' cells of the first, second and third row respectively.
4) The space due to inner hair cell loss was filled wish the nearest inner supporting cells which were hypertrophied and extended toward the space.
5) The distortion of the reticular lamina and the degeneration due to aging were regarded as two possible causes for the total loss of the organ of Corti near the basal portion of the first turn.