An extraordinarily complex interplay of joints, tendons, muscles and ligaments gives the shoulder joint the greatest range of motion of all the joints in the human body. The soft tissues that surround the bony structures of the shoulder play a vital role in driving and harnessing the joint. An array of muscles, tendons and ligaments give the joint static and dynamic stability and permit it to execute powerful and precise movements.
The powerful muscles in the upper arm and the back drive the shoulder joint powerfully in the desired directions and also protect the underlying rotator cuff. The function of the rotator cuff is to dynamically stabilize the shoulder joint - in particular, by keeping the humeral head precisely anchored in the dish-shaped portion of the shoulder blade.
Thanks to the complex interaction of a total of five joints and numerous muscles and their tendons, we humans are able to move our hands in all spatial planes and to reach things both near and far with our fingers.
Regrettably, this very complex structure also confirms the suggestion that increases in system complexity will necessarily lead to increased rates of malfunctioning. Disorders in the bony structures of the shoulder lead to changes in the soft tissues of the shoulder and vice versa. There is a clear correlation between chronic shoulder pain and disorders in the soft tissues of the shoulder, especially in the area of the rotator cuff.
This sets the stage for an array of shoulder joint disorders that can cause both acute and chronic shoulder pain:
- Impingement syndrome
- Rotator cuff tears
- Shoulder instability
- Calcific tendonitis
- Shoulder joint osteoarthritis
- Adhesive capsulitis (frozen shoulder)