Shoulder and the rotator cuff

The rotator cuff is a group of muscles and tendons that surround the shoulder joint, keeping the head of your upper arm bone firmly within the shallow socket of the shoulder. Rotator cuff injuries are common and increase with age. These may occur earlier in people who have jobs that require repeatedly performing overhead motions.

The rotator cuff muscles are the following:
Supraspinatus muscle
Subscapularis muscle
Infraspinatus muscle
Teres minor muscle

Rotator cuff problems occur through overuse, and they include tendonitis, bursitis, strains and partial and complete tears of the tendon.
Tendonitis is when the rotator cuff tendon becomes inflamed and irritated; bursitis is when the bursae swell. Tendonitis and bursitis cause pain in the front and side of the shoulder, and you might also feel some stiffness.

If you are at risk of rotator cuff injuries or if you've had a rotator cuff injury in the past, daily shoulder strengthening exercises can help prevent future injury.