 Hi, I'm Dr. Sushal Shantakumar. I'm a consultant shoulder surgeon practicing in Manipal Hospital's Bangalore. A rotator cuff can tear due to significant trauma. If you fall on your outstretched hand or if there is a direct impact to your involved shoulder, so the muscles around the shoulder can tear at that time. This is the lesser common cause. The more common cause which we see in our Indian population is due to aging. What happens is the muscles or the tendons are on the shoulder joint that degenerate over a period of time. It's gradual wear and tear as you get older. So it might be due to lack of blood supply in your involved muscles. It can be due to repetitive stress and it can also be due to some specific over-ed actions, some specific at-risk populations like diabetic or thyroid patients who are at risk to the muscle tears.