Complete study of the sella turcica requires multidirectional tomography. Radiographs (200) of normal adults were studied and the percentage of variants of each anatomical feature on both standard radiographs and tomograms were noted. The greatest drawback of the standard radiograph is the difficulty in objectively evaluating the effect of pneumatization and/or a septum of the sphenoid sinus on the sellar floor. In this series the floor was concave in 58% of patients, flat in 32.5% and convex in 9.5%. Lesions which simulate erosion of the posteromedial part of the lamina dura correspond to thinning of the central portion of the base of the dorsum sellae.