It is not generally appreciated that the thoracic aorta may be ruptured by nonpenetrating trauma. In this series of five new cases of occult injury of the thoracic aorta, a variety of orthopaedic injuries dominated the early clinical picture.

The cause is usually rapid linear deceleration secondary to an automobile or motorcycle accident. The lesion consists of a circumferential tear of varying size in the aortic wall, just distal to the left subclavian artery. The original tear may be temporarily scaled off. There is, however, constant danger of disintegration of the thrombus and exsanguination, especially during the first four weeks after injury. If the patient survives this early period the lesion matures into an aneurysm which, in time, may rupture months or even years later.

Fractures of the ribs, sternum, thoracic spine, or long bones are frequently present. Diagnostic findings which should arouse one's suspicions are unexplained shock, or more profound shock than would be expected from other injuries, hemothorax, dyspnea, hoarseness, and substernal chest pain. Widening of the mediastinal shadow seen on roentgenograms of the chest is the single most helpful finding. Aortography may be employed to confirm the diagnosis.

Once the diagnosis is made, and especially during the first thirty days following injury, immediate thoracotomy is indicated. The preferred method of surgical management consists in excision of the damaged segment and replacement with a teflon graft. Four of the five patients in the present report were treated sucessfully by surgery.

Since many of these patients are initially entrusted to the care of the orthopaedic surgeon, it is considered essential that he be familiar with this syndrome.