The shoulder joint consists of the humeral head and the scapula. It is a complex system that, from the functional point of view, includes 5 distinct articulations.

The cartilage that covers the articular surfaces protects the bones from direct friction and facilitates the relative sliding during the movements of everyday life.

The onset of some degenerative pathologies (arthrosis, arthritis) can lead to damage to the cartilage and to the reduction of its thickness: the bone surfaces therefore enter in direct contact causing pain.
A group of 4 muscles and respective tendons, called the Rotator Cuff, surrounds the joint giving it stability.