The rotator cuff is located in the shoulder. It comprises muscles and tendons that connect the bone of the upper arm, or humerus, to the shoulder blade, or scapula. They form a ball and socket joint that work together to create the most flexible joint in the body. Age, poor posture, injury, and excess lifting can increase the risk for damage to the rotator cuff. Injury can cause the tendons to become inflamed and, if left untreated, can become torn. Typically, rest and exercise therapy will help heal an injured rotator cuff. However, surgery is sometimes required.