This investigation of the optic canal is based on measurements of 60 macerated adult European skulls from the Alexander-Ecker Collection at the Anatomy Department of the University of Freiburg. An indian skull is also described, in which the cranial end of the left optic canal is closed by a bony plate. Computer tomographical and anatomical measurements were compared in order to assess the correlation of the two methods of investigation and the accuracy of the CT representation of osseous structures. The coronal projection of the optic canal proved to be optimal for CT examination--the sections meet the optic canal at an angle of 85.5 degrees. The measurements of transverse diameters correlate poorly, whereas vertical diameters and distances correlate well. The extent to which anatomical variations can be assessed by CT was also investigated. All anatomical variants could be observed in coronal sections, except the bony lamina in the Indian skull, which could not be seen until a contrast medium was used. The so-called "keyhole anomaly" appeared in 3.3% in our material, the "figure-of-eight" variant in 2.5%, and a carotid clinoid canal in 13.3%.