" Rotator cuff tears can be divided into: partial thickness rotator cuff tears, which are very common. Oftentimes patients present with the exact same findings: weakness and pain. In order to diagnose that, you need to get an MRI in terms of delineating between a full thickness and a partial thickness tear. That'd be very hard to determine that based on a physical exam or x-rays. An MRI would allow you to determine whether a rotator cuff tear is a partial thickness tear or a full thickness tear. A strain of the rotator cuff would be not uncommon in athletes, for instance: overhead athletes who are throwing - football players, baseball players. A strain would be some inflammation of the tendon or the muscle itself, but the actual tendon is not pulled off the bone. In a rotator cuff tear, the actual tendon has pulled off the bone, which is called the greater tuberosity. It's a bony prominence on the humeral head where the rotator cuff inserts and when the tendon tears, it pulls off that bone. "