Direct and CT measurements of canals and foramina of the skull base.

This investigation is based on measurements of 60 macerated adult European skulls from the Alexander-Ecker Collection at the Anatomy Department of the University of Freiburg. Computer tomographical (CT) and anatomical measurements were compared to assess the accuracy of the CT representation of osseous structures. Nine structures were examined: the optic canal; the superior orbital fissure; the foramen rotundum; the foramen ovale; the foramen spinosum; the foramen Vesalii (venosum); the carotid canal; the internal auditory canal, and the hypoglossal canal. The results show a good and even excellent correlation if the cranial opening is approximately at a right angle to the scanline. For this reason, the results of the coronal examination of the internal auditory canal are less satisfactory, and the coronal and axial measurements of the hypoglossal canal show only a moderately good correlation.