Scapulohumeral periarthritis often combines a wide range of pathology processes in soft tissue periarthric structures of shoulder. Development of a long head of biceps, subacromial bursitis, subdelta-shaped bursitis, tendinitis of a suspensory muscle and such-like conditions can appear as a result of initial degenerate changes conditioned by microtraumatism of a tendinous ligamentous apparatus or initial inflammatory changes when the process comes from adjoining structures, more often from articular surfaces.

Shoulder joint is the most disposed to traumas. Functional unity of tendons, ligaments and muscles provides stability to shoulder. Disorders of acromioclavicular joint are of crucial significance in pain development. Often there are changes in the area of shoulder “cup” and acromion. Shoulder “cup” is built of four muscles – two main (subscapular, infraspinatus) and two auxiliary (supraspinous and teres minor).

Joint distension. Muscular-articular misbalance leads to the increase of the tonus of an anterior bundle of a delta-shaped muscle and decrease of a back and middle bundle, as a result of which the head of a shoulder bone loses the rotation function which leads to the appearance of the trigger in the area of a delta-shaped muscle in the place of its fastening. The reverse rhythm of the scapula and the bone movement appears. There is a simultaneous lift of the shoulder and shoulder girdle which leads to the frequent traumatism of subclavicular and the serratus anterior muscles. Trigger points are frequently found in the back part of a delta-shaped and infraspinous muscles.