Fractures of the first and second ribs had a very low association with ruptured bronchus (2%) and ruptured aorta or brachiocephalic vessel (8%) in a series of 50 patients. Radiographic abnormalities indicative of ruptured bronchus include massive pneumothorax, pneumomediastinum, subcutaneous emphysema, and lobar or whole lung collapse which may fall to the dependent part of the thorax on erect views. Abnormalities pointing to a laceration of the aorta or one of the brachiocephalic vessels include widening of the superior mediastinum, shift of the trachea or nasogastric tube to the right, enlargement or indistinctness of the aortic knob, and widening of the right paraspinal line. One or more of these abnormalities indicates the need for thoracic aortography. In the absence of these abnormalities, aortography is not indicated solely by the presence of a first or second rib fracture on the chest radiograph.