The shoulder is one of the most complex and mobile joint complexes of the body. It is made up of three bones and three joints – the glenohumeral, acromioclavicular and scapulothoracic joints.
The glenohumeral joint is a ball and socket joint supported by muscles, tendons, and ligaments. The rotator cuff is a group of four muscles that support and move the joint with the help of tendons, tough bands of connective tissue that attach the muscles to the bones. The labrum forms a suction cup-like structure around the joint to provide stability. Further stability is provided by the ligaments that connect the bones.
Shoulder pain is a common problem that affects approximately 10 percent of the population at some point in their lives. Shoulder injuries can include both acute injuries and injuries that have a gradual onset relating to overuse and aging.