The fingers and thumbs of the hand are controlled by the flexor muscles lying in the lower forearm. Long tendons connect the flexor muscles to the bones of the hands. The flexor tendons run along the palmar surface of the hand, close to the surface of the skin. As a consequence, they are highly susceptible to injury, and a variety of accidents may sever or tear these tendons. These types of injuries are especially common in rugby, football, wrestling, and rock climbing.