The rotator cuff is the group of tendons and related muscles that help keep the upper arm bone seated in the socket of the shoulder blade. A torn rotator cuff tendon can cause pain, weakness, and limited range of motion in the shoulder.

A rotator cuff tear may be:

• Partial, in which only part of the fibers of the tendon are torn.
• Complete or full thickness, in which the tendon is torn all the way through.