I just got back from the hospital. I must have had six different tests to find out what's wrong with my shoulder. They finally diagnosed a torn rotator cuff. Why is it so complicated? Can't they just take one X-ray and see what's wrong?

The shoulder is a complex joint with many degrees of motion and many muscles to provide that motion. The main group of four tendons that surround and move the shoulder joint is called the rotator cuff.

These four tendons start out as four separate muscles. But by the time they attach to the shoulder, they are enmeshed as one unit. If the problem is in the rotator cuff, it takes a number of tests to sort out which muscle is affected and why. It could be a tendinitis (inflammation) or tendinosis (degeneration).

There could be a partial- or full-thickness tear of one (or more) of the tendons that make up the rotator cuff. And there isn't have one test that can sort them all out accurately. Usually, the physician does as many clinical tests as needed to direct the rest of the examination.

Advanced imaging is often needed to rule out or confirm a tear in the rotator cuff. X-rays only show structural changes in the bone (e.g., fracture, narrowed joint space, bone spurs, arthritic changes). Any injuries of the soft tissues resulting in tears require ultrasound, MRI, or arthroscopy to diagnose accurately.