Biceps Brachii

Some muscles have more than one origin (immovable end) or insertion (movable end). The "biceps brachii" in the upper arm, for example, has two origins. This is shown in its name, "biceps," which means "two heads." It is attached to the scapula (shoulderblade) in two places and extends along the front surface of the humerus (upper arm bone). It is inserted by means of a tendon on the largest part of the radius (lower arm bone). When it contracts, the movable end is pulled toward the origin, and the arm bends at the elbow.