Fine Morphology of the Sensory Cells in the Organ of Corti of Man

Abstract

The morphological characteristics of the sensory cells and neural elements in the human cochlea were studied with the electron microscope. The hairs of the outer sensory cells were arranged in a W form with at least six rows. The basal body or diplosomes were found in the cuticle free zone in the sensory cells. The subcuticular zones of the outer sensory cells frequently contained numerous osmiophilic inclusions. Two types of nerve endings, dendrites and axons, were observed below both the outer and inner sensory cells. The external spiral bundle was large and composed of numerous, closely packed nerve fibers. In specimens from older patients there were some evidences of nerve ending degeneration at the base of hair cells.

The findings in the human were compared with the normal and postmortem series of squirrel monkeys. When human specimens were fixed within a few hours of death, the ultrastructure of the inner ear could be investigated effectively, as is seen in the present study.