The body may be divided into three main areas for consideration of serious injuries: head and neck, trunk, extremities. Injuries to he head and neck give limited opportunity for effective medical treatment and early recognition is important. The trunk (chest and abdomen) is the site of of the most serious, life-threatening trauma. In abdominal injury there are three clinically and radiologically silent areas-the thoracic abdomen, the pelvis and the retroperitoneal space. In the thoracic abdomen there are injuries to three major organs: hepatic and splenic injuries, easily diagnosed by abdominal lavage, and diaphragmatic rupture, not easily diagnosed; only 25% of diaphragmatic ruptures present in a characteristic fashion. The others may show subtle abnormalities on the chest roentgenogram, such as slight blunting of the costophrenic angle and abnormal position of the nasogastric tube and stomach. In the pelvis there are also three organ systems that can be injured: the urinary tract, the rectum and the urinary bladder. In each case, the presence of blood - hematuria, gross or microscopic, and blood on the examining finger after rectal examination - signals the possibility of severe injury. The retroperitoneal space may also be the site of three important injuries - of kidney, usually flagged by developing hematuria; of pancreas and of retroperitoneal duodenum, each difficult to diagnose. Five signs may be present in a scout film of the abdomen: (a) slight scoliosis, (b) air in the duodenum, (c) no psoas shadow, (d) fracture of a lumbar vertebra or transverse process and (e) retroperitoneal air. Diagnosis and treatment must not be delayed.