抄録
Light microscopic and electron microscopic findings from a patient with Mondini type at right ear and Michel type at left ear genetic aplastic deafness are described. The round window of each ear was absent. The medial surface of stapedial foot plate of right ear was depressed roundly and it was covered by thick membrane. The course of the internal auditory meatus of left ear was deviated ventrally. The cochlea was presented by only three forths of turn at right ear and total aplasia at left ear. Three lows of spherical buldging thought to be outer hair cell were found between outer pillar cells and Hensen's cells. Round dome shaped modiolus of the left ear contained some nerve fibers and spiral ganglions sparsely. In the spiral ganglion cell, a small number of neurofibril and few Nissle Bodies were present in the cytoplasm. The saccule, utricle and semicircular canals of each ear were missing to make a common cavity. There were several otolith under the surface of membrane covered the common cavity. The sensory cells and its related tissues were not found in the both ear.
