Carotid canal dehiscence in the human skull.

Abnormalities of the floor of the carotid canal have been studied in 538 skulls. These abnormalities range from a fissure to total absence of the floor. This variation may be caused by abnormalities of the internal carotid artery or deficiencies in ossification of the skull base. CT suggests that these changes should be taken into account by surgeons working on the skull base.