We all have two rotator cuffs which are very important to our shoulder operation, one inside each shoulder. Your rotator cuff is made of four muscles that provide joint security (I love this term, a tiny little police force living in your shoulder making sure that the glenohumeral (shoulder) joint remains functioning). Why does your shoulder need a police force? Well the ball and socket joint of the shoulder is a bit rubbish (and also very good *). It is not like a caravan and car ball and socket joint where you have a deep strong connection (a bit like the hip). It is more like a scallop shell and a stick with a bulbus end. It fits ok, but really needs lots of tape and string to keep it together. Your rotator cuff muscles are the police, the tape and the string that hold this amazing joint together. The next part is only for reading if you are super interested in the names and actions of the muscles. The four muscles of the rotator cuff are: Supraspinatus - This muscles sit