A stinging in the shoulder girdle during a particular movement or the sudden inability to lift the arm over the horizontal are just two of the many discomforts that occur when the complex shoulder joint is worn out. We explain the causes of degenerative diseases of the shoulder, explain what forms of disease exist and how to treat them.
Shoulder: bony structures
When talking about the "shoulder", you are seldom aware of how complex the shoulder girdle is and how cleverly the individual bones, muscles and tendons are connected by joints, bursae and gliding layers.
In addition to the shoulder blade with the shoulder height (the acromion) and the raven beak procession (the processus coracoideus), the clavicle and the ball-shaped humeral head are also involved in bony structures at the shoulder joint. Although the actual shoulder joint is formed only by the humeral head and the small socket on the side of the scapula, but the shoulder height, collarbone and Rabenschnabelfortsatz form the roof and the lateral boundary of this joint.
In contrast to the hip joint, this joint does not have a large joint socket surrounding the condyle, but the articular surface of the scapula is almost straight. This has the advantage that in the shoulder joint movement in almost all directions is possible - unlike in the hip joint, where the large acetabular but provides stability, but also limits the mobility.
Disadvantage of this construction, however, is that many structures in the vicinity of the shoulder joint are used for its stabilization. If one of these structures fails, shoulder mobility is impaired.
In addition to the bones, the muscles with their tendons play an essential role in the structure and function of the shoulder. Particularly noteworthy are the muscles of the rotator cuff - these are muscles that are responsible for the rotational movements of the shoulder - namely the supra- and infraspinatus muscles, the subscapularis muscle and the teres minor muscle. The rotator cuff presses the humeral head against the socket, thus ensuring contact between the articular surfaces.
Between the muscles, the bones and the band fastenings are several bursae to ensure the mobility of the structures to each other. In addition, the deltoid muscle (deltoid muscle), located above the rotator cuff and the shoulder, plays a key role in the shape of the shoulder and gives it the typical curve. Furthermore, the biceps muscle (biceps is derived from Latin and means "two-headed") has a special task. Each of its two muscle bellies has a tendon that secures it to the bone.
The so-called long biceps tendon runs like a rope through the shoulder joint and maintains, especially in lateral movements of the arm, the contact between humeral head and articular surface upright.
How do you develop degenerative shoulder diseases?
The structures involved in building the shoulder joint are stressed during every shoulder-arm movement - day in, day out, all our lives. However, a smooth flow, especially the movements that take place with the arm away from the body, the abduction movements, only possible if the individual joints have no signs of wear such as osteoarthritis. In addition, the long biceps tendon must run well lubricated through its guide channel and the bursa between the muscles must allow a smooth muscle play.
Since the shoulder movement requires the interplay of so many structures, it is not surprising that different signs of wear can lead to a variety of clinical pictures.