Embryonic development of the human organ of Corti: electron microscopic study

A morphological approach by the electron microscope was used to obtain findings suggestive of the onset of auditory function in the fetal human cochlea. The organs of Corti at three different embryonic ages: 20 weeks 3 days, 22 weeks, and 24 weeks, were studied from the following standpoints: auditory hairs; hair cell bodies; the interrelationship between sensory cells and supporting cells; fluid spaces in the organ of Corti; and nerve endings to the sensory cells. Assessment of these findings implies that the peripheral auditory organ is ready for sending afferent impulses at around 24 weeks of embryonic age.