A bursa is a structure forming in a loose connective tissue in the area of muscles and joints where a bigger rubbing of these structures occurs. In lamellas of the connective tissue neighbouring with the muscle a crevice with walls with their structure corresponding to the synovial membrane of the joint occurs. Cells of the bursa produce a liquid corresponding to the synovial liquid.
In the area of the shoulder joint there are two basic bursae:
with a name derived from structures under which their position is. But an exact distinguishing of these structures is not always possible due to their ability to communicate with each other. Bursae can also occur on other places, and therefore it is important to think about their pathology whenever and wherever when a localized soresness or an oedema is there. In the case of extensive bursae, fluctuation is present. The bursa cannot be affected by pathological processes lonely, but a combination of the affection of the bursa and a present affection of tendons (most frequently tenovaginitis of the long head of the biceps) or glenohumeral articular capsule16 is very frequent.
picture of the subdeltoid bursa
16of structures with a similar synovial epithelium