How reliable is external examination in identifying internal injuries - Casper's sign revisited

Abstract

It has been proposed that the absence of injuries to the outside of a body that has been subject to blunt trauma indicates that the forces involved were relatively minor. It has also been suggested that an autopsy will be unlikely to uncover any significant injuries. A series of cases involving lethal blunt trauma from vehicle crashes and falls are described where minimal external injuries were associated with major disruption of internal organs. Skin is both resilient and elastic enabling it to resist injury, while allowing considerable forces to be transmitted to the musculoskeletal system and internal organs beneath. The absence of external injury is not, therefore, synonymous with lesser degrees of force, and should not discourage full medicolegal investigation of cases where occult trauma may be a possibility. As Casper was one of the earliest to describe this phenomenon, perhaps the term 'Casper's sign' should be used when massive internal injuries from blunt trauma are found in the absence of significant injuries to the skin.