Observation of Bony Structure of Skull

High resolution computed tomography (CT) scans reveal delicate anatomical structures in the brain. However, observation of bony structures by CT has been infrequently performed because the spatial resolution has not been suitable for that purpose. Using “Close-up Scan, ” which is a program loaded in the Toshiba TCT-60A, 35 observation of bony structure has been performed on all of the patients with pathological lesions. However, without detailed anatomical knowledge, it is quite difficult to evaluate the CT findings. Hence, using dried human skulls, CTs were taken in 2 and 5 mm slices and a comparative anatomical study was performed. The results were as follows: 1) “Close-up Scan” was performed on 7 dried human skulls with two sections, parallel to the orbito-meatal line (OM-line), and at right angles to the OM-line. 2) A 2 mm slice is more suitable for the observation of delicate anatomical structures or discrimination of two objects which are close to each other. A 5 mm slice is useful for the observation of a structure which is parallel to the OM-line or to reveal the total image of small canals. 3) In slices parallel to the OM-line, small canals and sutures can be revealed dramatically, except for structures which are parallel to the OM-line. 4) Coronal slices are suitable for the observation of the paranasal sinus, orbita, and petrous part of the temporal bone. Furthermore, the entire path of the facial nerve within the petrous bone can be observed with axial slices. As described above, results of these comparative anatomical studies will be useful for the evaluation of bony structures in clinical cases.