Trauma is a physical injury caused by transfer of energy to and within the person involved. Abdominal trauma is best categorised by mechanism as blunt or penetrating abdominal injury. The mechanism of injury dictates the diagnostic work-up. As there is a broad spectrum of abdominal injuries, abdominal trauma patients are often difficult to assess. Confounding factors, such as associated extra-abdominal injuries or altered mental status (either from a head injury or intoxication), further complicate the evaluation.  Hepatic injury is the most common intra-abdominal organ injury.
This topic includes the evaluation of abdominal trauma in adults only. For information on abdominal trauma in children, please go to the Assessment of abdominal pain in children topic.
The surface anatomy of the abdomen extends from the nipple line to the groin crease anteriorly and from the tips of the scapulae to the gluteal skin crease posteriorly. The specific anatomical boundaries of the abdomen are the diaphragm, abdominal wall musculature, pelvic skeletal structures, and vertebral column. There are 3 basic regions of the abdomen: the peritoneal cavity with its intrathoracic component, the retroperitoneum, and the pelvic portion. As the diaphragm rises as high as the fourth intercostal space, trauma to the lower chest may involve abdominal organs.
Causes of blunt abdominal trauma include motor vehicle accidents (MVAs), motorcycle crashes (MCCs), pedestrian-automobile impacts, falls, and assaults. MVAs are the most common cause of blunt abdominal trauma, causing about 75% of such injuries. In the US in 2016 there were 37,461 fatalities from 34,439 fatal MVAs, 5286 fatalities related to MCCs, and 5987 pedestrians struck.  In about one third of these deaths, alcohol was involved.  Prevention strategies, such as campaigns against driving while intoxicated and encouragement of seatbelt use, have been shown to be effective in decreasing blunt abdominal trauma-related morbidity and mortality.    
Blunt abdominal trauma can result in multiple different organ injuries. Complications of blunt abdominal trauma include peritonitis, haemorrhagic shock, and death. Common injuries are divided into 2 categories: solid organ (e.g., liver, spleen, pancreas, kidneys) and hollow organ (e.g., stomach, large and small bowel, gall bladder, urinary bladder) injuries. Solid organ injuries range from minor injuries such as small, haemodynamically insignificant liver, spleen, or kidney lacerations to devastating injuries requiring immediate intervention. Bowel injuries require surgical repair to prevent peritonitis and septic shock.
Diaphragmatic injury accounts for <10% of blunt abdominal trauma, and splenic injury is more common with blunt than penetrating abdominal trauma.
Penetrating abdominal injuries occur when a foreign object pierces the skin. The most common penetrating injuries are gunshot wounds and stab wounds. In the US, penetrating trauma remains a major cause of morbidity and mortality, with 30,143 firearm-related deaths occurring in 2005. Of these deaths, 29,354 were intentional (i.e., suicide or homicide) and 789 were accidental. In European countries, firearm-related injuries are much less common.
The external appearance of the penetrating wound does not determine the extent of internal injuries. It is important to define the trajectory of a penetrating wound and to consider all possible internal injuries. The mortality associated with penetrating abdominal trauma is related to the intra-abdominal organs injured, with refractory haemorrhagic shock being the leading cause of death. 
Stomach, small bowel, and colorectal injuries occur more frequently following penetrating abdominal trauma than following blunt trauma. The small bowel is the organ most commonly injured by penetrating abdominal trauma.
Pancreatic injury is more common with penetrating than blunt abdominal trauma, and there is a high incidence of diaphragmatic injury in thoraco-abdominal penetrating trauma.
Associate Professor of Emergency Medicine
Associate Research Director
Department of Emergency Medicine
UC Davis School of Medicine
DN is an author of a reference cited in this topic.
Dr Daniel Nishijima would like to gratefully acknowledge Dr Jeffrey A. Claridge and Dr Jeffrey W. Carter, previous contributors to this topic. JAC and JWC declare that they have no competing interests.
Aberdeen Royal Infirmary
Royal Army Medical Corps (V)
Honorary Senior Lecturer
University of Aberdeen
University of Swansea
JJ declares that he has no competing interests.
Harwell Wilson Professor and Chairman
Department of Surgery
University of Tennessee Health Sciences Center
TCF declares that he has no competing interests.
Associate Medical Director
Consultant Emergency Medicine
Guy's and St Thomas' NHS Foundation Trust
Clinical Lead and Consultant
Accident Emergency Medicine
St Thomas' Hospital
AP declares that he has no competing interests.
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