Tricep Posterior pronation

Here we have a posterior view of the brachium with emphasis on the Triceps and the first stages of Pronation.. Also we got a bit of info on the extensor tendons,( extensor digitorum, indicies, and policis longus)  and how their branchings  insert into the phalanges.

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 .

Shoulder Girdle

The Shoulder girdle is in essence a pelvis that has evolved to allow for the brachia apparatus, i,e,. mechanical specialization of the humerus and shoulder that facilitates the the needs of  the pronated hand and opposable thumb. Freed from it's primary purpose of translocation and isonomic channeling (dispersion of gravitational force) which defines the structure of the pelvis , the Sacrum ,Ilium and Ischia have now separated and the scapula takes shape- becoming the Ischia and Ilium of the shoulder. These free floating "pelvic halves"allow for a greater range of movement than a fixed pelvis could ever allow..Clearly it is evident that he pubic bone of the pelvis is analogous to the clavicle of the shoulder girdle. With a bit of imagination it can also be observed that the Coracoid Process of the Scapula is analogous to the Pubic Bone of the Pelvis.