The usefulness of computed tomography (CT) has rapidly become recognized in the diagnosis of intracranial pathology, and recently in the interpretation of soft tissue diseases in other parts of the body. This is due to its ability to visualize slight differences in X-ray absorption by soft tissues, which is not possible with ordinary roentgenography. Lesions within tissues which could not be recognized are now seen as higher or lower densities when compared with normal tissue in axial transverse cross sections of the human body as X-ray images. However, in order to identify the lesion, and the tissue in which it exists, anatomical knowledge of an axial cross section of the normal body is necessary, because we have become accustomed to relying on normal roentgenographic images for X-ray diagnosis, and generally neglecting interpretation of axial cross section images. The correct interpretation of two dimensional images of the human body requires a thorough training in reading of normal axial transverse cross section images.