Cuts to the offender's own hand--unintentional self-infliction in the course of knife attacks.
In a knife attack the perpetrator can unintentionally injure his own hand, if the knife does not have an adequate handguard and the tip of the blade hits a solid, mostly bony structure while being violently thrust into the victim's body. The injuries occurring under these conditions are localized on the flexor side of the knife-holding hand and may include the index, middle, ring and little fingers. They are seen particularly often on the little finger at the level of the proximal phalanx and in the skin fold of the proximal interphalangeal joint. The majority of these cuts run transversely to the longitudinal axis of the fingers and can show a step-like arrangement with different distances to the metacarpophalangeal joints, often from ulnar-proximal to radial-distal. In the six cases presented the injuries were most pronounced on the ulnar side of the hand. When the flexor tendons of the fingers are also severed and the tendon stumps are strongly retracted this indicates that the fist was firmly closed at the time of the injury.