This paper reviews evidence and ideas on closed accidental rupture of the aorta, and refers to an analysis of 37 subjects in whom traumatic aortic ruptures were found at necropsy. The mechanisms of rupture of the ascending aorta and the proximal and distal parts of the descending aorta are discussed. Aortic rupture is one of the major causes of rapid death after traffic accidents, especially in occupants of motor vehicles. However, about 20 per cent of subjects survive for hours, days or longer after the accident, allowing time for surgical repair in some cases.