The arm has a wide range of movements, they swing backward and forward in walking and running, and they can be folded across the chest or raised above the head. The shoulder forms a base for the arm with most of the upper arm muscles originating from this area. In the upper arm, the biceps and triceps are arranged to give the forearm power to thrust and bend. The two muscles join at the elbow and allow you to bend and straighten your arm and also rotate your wrist and hand. The forearm muscles transmit power to the wrist, hands, and fingers. A group of flexors and extensors controls the movements of the wrist, acting in conjunction with other muscles of the fingers, thumb, |radius|, and |ulna|. These sets of muscles allow the arm and wrist to bend (flexion) and straighten (extension) as well as move outward away from the body (abduction) and inward toward the body (adduction). Some of these muscles participate in more than one type of movement.
