Canine Brachium

Dogs have disconnected shoulder bones (lacking the collar bone of the human skeleton) that allow a greater stride length for running and leaping.Consequently this specialization shrinks the biceps, as the scapula lacks the bony coracoid process onto which it can anchor. The supraspinatus muscle enlarges, filling out over half of the scapula surface. The deltoid muscles shrink as they lack the bony ridge of the clavicle from which to emerge, and the triceps take on a more important role in translocation. Most interesting is how the radius has pronated and then locked itself in, although it hasn't fused like a horses radius and ulna .