text: what is 3rd degree shoulder separation?   most people think a shoulder separation refers to the actual should joint; the ball and socket.  it does not.  a shoulder "separation" is a sprain of the acromioclavicular joint, also commonly referred to as the "a-c joint".  the acromomion process is a piece of your shoulder blade that sticks up at the top, and the clavicle is your "collar bone".  this joint can be sprained just like any other joint in the body, and  a sprain indicates that the ligaments that hold 2 or more bones together has been injured.  there are 3 grades of ligaments injury:  grade 1: microscopic injury of the ligament without lengthening of the ligament itself.  grade 2: partial tearing of the ligament with some lengthening of the overall structure.  grade 3:  complete tear of the ligament.  the ligament is in two pieces and the joint is unstable.  the good news?  grade 3 shoulder separations typically heal over a few weeks with no long term problems.  they will often end up permanently deformed with a hard bump sticking up on top of the shoulder.  however, this is usually just a cosmetic problem unless you participate in very heavy contact (football, hockey) or intense weight training.