The liver can be injured by two principal injury mechanisms: blunt and penetrating trauma. Motor vehicle crashes account for the majority of blunt injuries, whereas gunshot wounds and stabbings constitute the major cause of penetrating injuries. A 2017 review of 10years of outcomes for hepatic trauma in the UK showed that, of 4368 cases of hepatic trauma, 81% were caused by blunt injuries with 19% due to penetrating trauma. typical for other European centres, the experience in South Africa, where penetrating injuries account for 66% of liver trauma, North America, where up to 86% of liver injuries are penetrating wounds.

The severity of liver trauma ranges from a minor capsular tear, with or without parenchymal injury, to extensive disruption involving both lobes of the liver with associated hepatic vein or vena caval injury. The American Association for the Surgery of Trauma has adopted for general use the classification of liver injury described initially in 1989 by Moore and colleagues, and revised subsequently in 1994 injury grade is calculated from assessment of the liver injury using information derived from radiological study, operative findings or autopsy report. Where there are multiple injuries to the liver, the grade is advanced by one stage. As stated previously, it is the physiological status of the patient rather than the anatomical grade of injury that dictates management. Grade I–III injuries are considered minor; they represent 80–90% of all cases and the majority can be managed non­operatively. Grade IV–V injuries are considered severe injuries and non-operative management or surgical intervention can be applied depending on the patient’s physiology and clinical progression. Grade VI lesions are generally regarded as incompatible with survival.