Traumatic rupture of the aorta at the level of the arch is an exceptionally rare lesion (Charles et al, 1977 Radiographic studies showed a widened mediastinum and a fracture of the right tibia. As a traumatic rupture of the thoracic aorta was suspected he was transferred to our department, where an angiographic study was immediately performed. This showed a rupture of the aortic arch and defective filling of the brachiocephalic vessels ( fig 1).As the patient's condition was rapidly deteriorating, he was taken to the operating theatre, where a median sternotomy was performed. Cardiopulmonary bypass was available. After the pericardial sac had been opened, direct inspection showed a previously unsuspected retro-oesophageal position of the aortic arch, which was obviously the site of the laceration. The adventitia was still intact. The brachiocephalic vessels were abnormal in origin. The first branch of the arch was the left carotid artery, next arose the right carotid artery, and lastly the right subclavian artery originated from the posterior surface of the distal ascending aorta (fig 2).As it appeared impossible to reach the aortic tear through this approach, the sternum was closed and a left posterolateral thoracotomy in the