APPROXIMATELY one half of the deaths from auto accidents result either directly or indirectly from thoracic injury.<sup>1</sup>Serious injury to the thoracic contents may exist with absent or mild symptoms, and therefore, a careful radiologic investigation of the thorax is important in all patients with known chest trauma or those involved in serious accidents, whether or not they have chest symptoms. Thoracic injuries range from such relatively unimportant problems as simple rib fracture to great-vessel laceration, which, if not recognized and treated promptly, will almost certainly result in the death of the patient. Fortunately, the roentgenogram will demonstrate most of the significant injuries. In this presentation, discussion of injuries to the heart and great vessels will be omitted. <h3>Thoracic Cage</h3> Injury to the thoracic cage is similar to that of the skull in that the state of the bony framework tells little about damage to the underlying viscera. Fractures