One of the most common injuries to the shoulder is an injury to the rotator cuff. The rotator cuff is like four pieces of rope. These ropes are responsible for lifting your arm. You may think it is the big muscles on the sides of your shoulders that perform this movement, but they are really responsible for strength and power. The pieces of rope or rotator cuff, actually perform the fine movements that you do with you shoulder. Well, as you can imagine, a rotator cuff can tear in two ways just like a rope can tear in two ways. It can fray causing a partial rotator cuff tear which is very common. Or it can tear completely through the rotator cuff. In this case it may require a surgical procedure to be repaired.