Muscles of the side and back, historical artwork. The skin and fascia (connective tissue) have been removed to expose the muscles (red) of the side and back of the body and their points of attachment. The trapezius muscle (upper centre of back) moves the scapulae (shoulder blades). The largest muscles on the back are the two latissimus dorsi muscles (lower left and right of back), which move each arm. Image taken from Atlas d'Anatomie by Jules Cloquet, France, 1825.