A gun shot wound can not be evaluated as entrance or exit wound due to surgical alteration of wound. The phenomenon is called

Kennedy phenomenon A gun shot wound can not be evaluated as entrance or exit wound due to surgical alteration of the wound. In case of shored exit wound also confusion may arise. This occured in the case of John F Kennedy's assassination. A surgically altered shored exit wound on the the back of the neck was misinterpreted as an entrance wound. Ref: FORENSIC MEDICINE AND TOXICOLOGY Dr PC IGNATIUS THIRD EDITION PAGE 155