The rotator cuff is made up of muscles and tendons that hold the shoulder in place. The rotator cuff can become injured or wear down with age. If injured, the rotator cuff may need surgery to repair it.
Any one of the rotator cuff tendons can fray or tear from causes such as injury and overuse. A tear may be partial, with some of the tendon still intact. Or it may be a complete tear, with the tendon fully torn.
The tendons of four muscles in the upper arm form the rotator cuff, blending together to help stabilize the shoulder. The rotator cuff tendons allow you to raise and rotate your arm. This video discusses what happens when these tendons are damaged.