Comparative Anatomy- The forelimb

Here I have superimposed the actual bone on a demo drawing to illustrate how the radius has evolved/devolved based on survival imperative.I've laid out the human dog, and horse brachia to illustrate this.Most obvious is the lack of clavicles in the dog and horse and the gradual restricted movement of the radius in the dog to total fusion of the ulna with the radius in the horse into permanent pronation.