The shoulder joint is the joint with the largest range of motion, the largest number of components, and the most complex kinematics of all joints in the human body. In clinical practice, shoulder pain is very common, with a statistic showing that the incidence of shoulder pain is 11.2/1000 person-years, but at present, our understanding of shoulder pain is still limited. However, studies have shown that most of these cases are left with some disability after treatment. In fact, the term “frozen shoulder” is a vague concept and is a general term for painful disorders around the shoulder joint. As research into shoulder disorders has progressed, it has been found to include many periarthritic disorders, including rotator cuff injury, traumatic anterior shoulder instability, SLAP injury, Bankart injury, HAGL injury, glenohumeral arthritis and other shoulder disorders, while statistics show that 44-65% of shoulder pain is caused by subacromial impingement syndrome SAIS. The main clinical manifestation of SAIS is increased pain during shoulder abduction, which reduces shoulder motion and seriously affects the quality of life of patients. As early as 1972, Neer5 recognized the subacromial space anatomically and proposed the concept of subacromial impingement syndrome. The subacromial space is a potential space above the humeral head with the acromion, rostro-capital ligament and the underside of the acromioclavicular joint, which is filled with the supraspinatus tendon, the subacromial bursa, the long head of the biceps tendon and the glenohumeral capsule, and lesions of these filling structures can cause SAIS. In 1983, Neer divided SAIS into three stages: stage I, when the subacromial structures are congested and edematous; stage II, when the subacromial structures are degenerated; and stage III, when the subacromial structures are further degenerated, with the formation of bony redundancy and damage to tendon structures. However, Neer only staged SAIS in terms of pathological changes, but could not directly elucidate the mechanism of SAIS to guide clinical treatment. Later, scholars7 classified SAIS into primary and secondary SAIS, congenital and acquired SAIS, and static and dynamic SAIS according to different mechanisms and classification methods. The current treatment methods for SAIS are diverse, but can be mainly categorized into two aspects: conservative treatment and surgical treatment. Rehabilitation treatment is carried out earlier and surgery is generally considered only when rehabilitation treatment is ineffective in patients. Conservative treatment methods include: rotator cuff strength training, rest, oral NSAIDs, subacromial glucocorticoid injections, behavior modification, physical therapy, and acupuncture.