Bone spurs in the shoulder are a byproduct of what many will call impingement. However impingement is a symptom and not a cause in my eyes. These bone spurs in my opinion are caused by the humerus hitting the acromion OR the acromion hitting the humerus. In either case it is the scapula's dysfucntion that makes this situation occur. If the scap is moving too slow it can't get out of the way, if it's surrounding musculature isn't strong enough to slow it down when the humerus is returning to the axial position, then the acromion will bang on the humerus. After many years spurs develop.
So what do you do? Educate the scap to do what it's suppose to do which is work in conjunction with the other muscles of the body not in isolation.
what slow down the scapula? Everything below it.