Bursa sacs

Bursae are fluid-filled, capsule-like, delimited cavities that lie outside the joint space and cushion strong mechanical stress. Bursae are either congenital or acquired (reactive bursae). Depending on the mechanical load, each person develops bursae of different sizes in different places.

Due to this high individual variability, it is not possible to give an exact indication of the location of the bursae. The subacromial bursa is a bursa located below the acromion, a bony extension of the shoulder blade. Another large bursa (bursa deltoidea) is located between the triangular muscle and the humerus.

The bursa is often located below the tendon of the subscapular muscle or below the coracoid process and is connected to the articular cavity of the shoulder joint. Due to the imbalance between the head of humerus and the articular surface of the scapula and the weak ligament securing of the shoulder joint, the shoulder joint tends to dislocate (dislocation). Most often, the head of humerus luxates forward and front-down, especially when the upwardly stretched arm is rotated forcibly, which is why this injury often occurs in sports accidents and falls.

After the first luxation, which still requires massive trauma, further luxations often occur. In these cases, slight twisting is usually sufficient to cause dislocation of the shoulder joint. These habitual luxations often occur even during sleep and are extremely unpleasant.

A dislocated shoulder is very painful and of course cannot be moved. Such recurrent dislocations can lead to an injury to the cartilage and even the underlying bone (so-called impressions), which are known as Hill-Sachs lesions. Shoulder joint arthroses are quite common.

It is a degenerative disease caused by wear and tear of the cartilage that covers the joint surfaces of the shoulder and is accompanied by severe pain and restricted mobility. In severe cases, a shoulder prosthesis can be used here.The impingement syndrome is caused by entrapment of connective tissue (capsule or tendon tissue) or wear and tear of the joint structures, which massively impairs mobility, especially the spreading of the arm and rotation. The frozen shoulder is a temporary stiffening of one or both shoulders.

Severe pain in the shoulder joint is followed by relatively painless restrictions of movement. Ideally, the pain subsides of its own accord. The traumatic tearing of the cartilaginous lip (labrum glenoidale) at the articular surface of the shoulder blade is known as a Bankart lesion and is one of the causes of habitual dislocations.