Abstract
In an 18-year-old male, the Eustachian tube was abnormally wide and passed through the large pterygoid cavity bilaterally. Furthermore he had bilateral cup ears, congenital aural fistula, the narrowed ear canal with the small ear drum, malformations of the ossicular chain with vestibular window anomaly, and exposed facial nerves bilaterally. His audiogram indicated severe conductive deafness with typical Carhart's notch bilaterally. Vestibular dysfunctions and mental retardation were not obseved.
CT examinations revealed a broad cavity containing the tympanic cavity and the pterygoid cavity with good aeration bilaterally. In this case, the apex of the petrous part of the temporal bone and a part of the wings of the sphenoid bone might have not been developed. As an embryological consideration, developmental disorder must have taken place during the 8th week of gestation, when a constriction between the tube and the tympanic cavity would have been formed. It is also very interesting that normal dolphins have the similar large tympano-pterygoid cavity.
