Traumatic basal subarachnoid hemorrhages: autopsy material analysis.

Fourteen cases of traumatic basal subarachnoid hemorrhages, examined in the years 1980-1988, were presented. Bleeding was connected with the fracture of the transverse process of the atlas in eleven cases and with atlanto-occipital dislocation in three. The source of hemorrhage--vertebral artery rupture--was determined only four times. In nine cases (63%) atlases showed various developmental malformations (posterior ponticle and foramen arcuale, epitransverse process, incomplete ossification of the transverse process). The results were related to the literature of the subject. Special attention was paid to the mechanism of the rupture of the vertebral arteries in which developmental disorders and pathological conditions may play an important role.