The shoulder joint is the topmost part of the upper limb, a joint with the greatest mobility of the whole body, and is divided from the neck by the lateral 1/3 of the upper edge of the clavicle and the lateral 1/3 of the line from the acromion of the shoulder to the spinous process of the 7th cervical vertebra. The line connecting the anterior upper end of the deltoid muscle and the midpoint of the anterior axillary crease is the boundary with the chest; the line connecting the posterior upper end of the deltoid muscle and the midpoint of the posterior axillary crease is the boundary with the back; and the boundary with the arm is the lower edge of the anterior axillary line and the lower edge of the posterior axillary crease circular line, which includes the axillary area, the deltoid area, and the scapular area. Shoulder joint is one of the most movable joints in the human body, and due to frequent activities, the incidence of shoulder joint diseases gradually increases with age.