The rotator cuff is a tendon-muscle sheath made up of four muscles; m. supraspinatus, m. infraspinatus, m. teres minor and m. subscapularis. This four muscles are very important to ensure the stability of the shoulder. The main function of the rotator cuff is the dynamic stabilization of the humerus head. Damage to only one of these muscles significantly reduces the function of the shoulder, relatively arm. The clinical picture includes shoulder pain, mostly on the outside of the upper arm, details of work involving raising the arms above shoulder level, pain during the night that prevents sleeping on the diseased shoulder, lack of fluidity, development of arthritis and calcifications in the shoulder joint and difficulties in performing, otherwise, simple everyday tasks. The main diagnostic tools are medical history, clinical examination, ultrasound and magnetic resonance imaging, which can be used to assess the ruptured tendon and the size of the rupture itself. These are mostly degenerative ruptures in the elderly, but rupture can also occur in younger people as a cause of overload. The most common ruptures in young people are partial ruptures that can become complete over time. In most cases the supraspinatus tendon is damaged due to its position and function. Elderly people, who do not have major difficulties, are advised to avoid heavy loads and take non-steroidal anti-inflammatory drugs with physical therapy, and younger and more active patients are recommended surgical treatment. Surgery is important because tendon shortening and retraction occurs, and later reconstruction is often less possible. This article shows the importance of the rotator cuff on the funcionality of the shoulder girdle in human life. Problem rotator cuff disease may be the result of either a substantial injury to the shoulder, progressive degeneration or wear and tear of the tendon tissue.