Stabbed

Mechanism

The human skin has a somewhat elastic property as a self-defense; when the human body is stabbed by a thin object such as a small kitchen knife, the skin often closes tightly around the object and closes again if the object is removed, which can trap some blood within the body. It has thus been speculated that the fuller, an elongated concave depression in a metal blade, functions to let blood out of the body in order to cause more damage. This misconception has led to fullers becoming widely known as "blood grooves". The fuller is actually a structural reinforcement of the blade similar in design to a metal I-beam used in construction. However, internal bleeding is just as dangerous as external bleeding; if enough blood vessels are severed to cause serious injury, the skin's elasticity will do nothing to prevent blood from exiting the circulatory system and accumulating uselessly in other parts of the body.