The introduction of the operation microscope and the progress of the hearing test apparatus into otology drastically altered the performance of tympanoplastic operations. The lack of application of the diagnostic aid sometimes forces the otologist to perform exploratory operations, as the conventional roentgens of the temporal bone, which usually provide information concerning the cholesteatoma, only pneumatization of the mastoid cells and inflammatory changes, rarely reveal pathologic

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... s in or near the ossicles. Thus we prefer the tomographic examination as a routine method. According to our experience with about 250 cases of ear tomography, posteroanterior projection of the temporal bone proved to be the most suitable for demonstration of the ossicles. We used Princeps 60 type tomographic apparatus with the use of the plesiosectional casette, which involved five sets of matched intensifying screens. On our Princeps 60 tomography, the tube-film distance is 85cm. and the extent of the tube is 30. The resultant film gives excellent visualization of anatomic details such as the ossicles, radiologic spur, cochlea, lateral semicircular canal, internal meatus, etc. In the preoperative tomographic examination, we added a lateral projection using a polytomographic apparatus, Toshiba C type.