The tympanic cavity: tomographic anatomy.

This study was carried out on 100 tomograms of the petrous bone using Guillen's transorbital view of the anatomy of the middle ear. It provides basic data concerning the morphology, size and surface area of the tympanum, the epitympanum and the hypotympanum. It correlates the surface area of the epi-and hypotympanum, and suggests certain embryological interpretation. This study contributes to the diagnostic radiology of the middle ear in the following ways: I It provides basic data for the interpretation of tomograms in patients with ossicular dislocation. 2 It provides essential data for the radiology of congenital malformation and of tumors. 3 It puts in perspective certain criteria used for the diagnosis of cholesteatoma. Finally, this study justifies the use of preoperative radiological investigation.