Shoulder anatomy diagram. The shoulder is one of the most sophisticated and complicated joints of the body. It has the greatest range of motion of any joint. The anatomy of the shoulder girdle consists of several joints, or “articulations”, attaching the upper limb to the rest of the skeleton. The muscles of the shoulder bridge the transitions from the torso into the headneck area and into the upper extremities of the arms and hands. The shoulder is a complex combination of bones and joints with muscles offering the widest range of motion of any part of the body.