The rotator cuff is a group of muscles and tendons that hold the shoulder joint in place and allow you to move your arm and shoulder. Problems occur when part of the rotator cuff becomes irritated or damaged. This can result in pain, weakness and reduced range of motion.
Sometimes a bone spur forms on a shoulder bone called the acromion. "Subacromial" refers to the space beneath this bone. A bone spur in this location irritates and frays the rotator cuff tendon directly underneath. To relieve pressure on the tendon, a "decompression" procedure may be performed.
Often, a surgeon can accomplish this with an arthroscopic procedure — inserting a camera and tools through small incisions. This operation is called an arthroscopic subacromial decompression. The surgeon grinds down the spur and smoothes the bone. He or she may also clean the frayed portions of the tendon by shaving them.