Congenital middle and inner ear anomalies.

For this study, 100 human temporal bones from 73 individuals, aged 31 gestational weeks to 39 years, each with anomalies of the middle and/or inner ear, were studied to identify the features, locations, and frequencies with which congenital anomalies occurred in these structures. The temporal bones had been removed at autopsy, fixed, dehydrated, embedded in celloidin, sectioned horizontally or vertically at 20 microns, stained with hematoxylin and eosin, and studied under a light microscope. The anomaly in the middle ear most often found was wide dehiscence of the facial canal; hypoplastic cochlea was most frequently observed anomaly in the inner ear. The implications of these findings for development of the ear during fetal life are discussed.