Frequency
Wear-related shoulder diseases often occur. More common than shoulder arthrosis are diseases of the muscle and tendon structures of the shoulder joint (acromion). Particularly noteworthy here are diseases of the rotator cuff tear, calcified shoulder (tendinosis calcarea) and the impingement syndrome. Studies have shown that the frequency (prevalence) of shoulder complaints can be 8% or more. Wear-related changes in the main shoulder joint (glenohumeral joint) occur in about 30% of people.
Anatomy of the shoulder
The shoulder joint (glenohumeral joint) is formed by the head of the humerus and the glenoid cavity of the shoulder blade (scapula). The head of humerus has a joint surface 6 times larger than the corresponding surface of the glenoid cavity. The enormous range of movement of the shoulder joint that can be achieved in this way is only possible due to the small bony joint space.
In most other joints, the bony guidance is much stronger (e.g. hip joint). This lack of stability is compensated by a complex muscle, tendon and ligament apparatus. The precise interaction and the sensitive balance of the muscles involved (especially the rotator cuff) ensure that the head of humerus is in correct contact with the glenoid cavity in every arm position.
- Humeral head (humerus)
- Shoulder height (Acromion)
- Shoulder corner joint
- Collarbone (Clavicle)
- Coracoid
- Shoulder joint (glenohumeral joint)