often, as a therapist, working along lines of movement that influence the shoulder itself is where we can reinforce efficient and better technique in the movement of the joint and ensure healthy and functional operation.  These 'secondary movers' are also advantageous when you are in the middle stage of rehabilitation where acute pain is donwgraded, but functional movement is still restricted.  Detailed work here can contribute to effective bio-mechanics of the joint for future pain free movement.