Blunt, sharp or surgical trauma is increasing. Sharp trauma, that is, stabbings and gunshot injuries, are usually easily recognised. Blunt trauma may cause damage to the arterial lining, allowing it to separate and block the artery. Either direct trauma, from a blow, or indirect trauma, secondary to an orthopaedic injury, may occur. Over-extension of joints may result in small branches detaching and the development of aneurysms. Both arteries and veins can be damaged accidentally during surgical procedures. Failure to recognise this damage can result in the development of symptoms, sometimes very rapidly but, at other times, delayed for weeks or months.