Temporal bone study of trisomy 13 syndrome.

The temporal bones of a 23-week-old female who had multiple congenital anomalies and bilateral hearing loss with trisomy 13 syndrome were evaluated under light microscopy. In the left cochlea, spiral ganglion cells and cochlear nerve fibers are absent. In the right ear, an abnormal branch of the singular nerve passes between the utricle and lateral semicircular canals and separates the two portions, one to the flattened crista of the lateral semicircular canal, the other to the utricular macula. This is a rare report describing a patient with abnormalities in three nerves, including the facial, vestibular, and cochlear nerves.