Frequency and localization of congenital anomalies of the middle and inner ears: a human temporal bone histopathological study.

This study investigated congenital anomalies occurring in the middle and the inner ears, with particular attention to their features, localizations, and frequencies. One hundred human temporal bones obtained from 73 individuals, aged 31 gestational weeks to 39 years, each of whom had anomalies of the middle ear and/or inner ear, were used for this study. The temporal bones had been removed at autopsy, fixed, dehydrated, embedded in celloidin, and sectioned horizontally or vertically at 20 microns. Every 10th horizontal section or every 20th vertical section was stained with hematoxylin and eosin, mounted and studied under a light microscope. In the middle ear the structure most often found to be anomalous was the facial nerve; in the inner ear it was the lateral semicircular canal. The implications of the anomalies observed are discussed as they relate to fetal development, dysfunction of the ear, and clinical interpretation of diagnostic radiological studies.