1. Shoulder causes (1) The disease mostly occurs in middle-aged and elderly people over 40 years old, with degenerative soft tissue lesions and weakened ability to withstand various external forces; (2) Chronic injury-causing force from long-term over-activity and poor posture; (3) Longer shoulder fixation after upper limb trauma, with secondary atrophy and adhesion of peri-shoulder tissues. (4) Acute contusions and strains of the shoulder due to improper treatment, etc. 2.Extra-shoulder factors Cervical spondylosis, shoulder entrapment pain occurring from heart, lung and biliary tract diseases, persistent spasm and ischemia of shoulder muscles due to long-term failure to heal from the original disease and the formation of inflammatory lesions, transforming into true frozen shoulder. Chinese medicine etiology: modern Chinese medicine clinical summary of ancient experience and combined with empirical research, the onset of frozen shoulder is believed to be related to insufficient qi and blood, external wind, cold and dampness, and flash and strain injury, and injury to the tendons and veins around the shoulder, resulting in qi and blood blockage and pain, resulting in bone paralysis. In the classical Chinese medical text “Suwen Paralysis”, there are categories of bone paralysis, tendon paralysis, pulse paralysis and skin paralysis, which are considered to have causes related to wind, cold and dampness. It was first proposed in the chapter of “Ling Shu Thieves’ Wind” that its pathogenesis was closely related to trauma, and it was believed that after injury, the bad blood would be stored between the muscles and tendons, and the Qi and blood would not run smoothly and be easily invaded by wind, cold, and dampness, and the paralysis would occur when the bad blood and external evil attacked. In the Sui and Tang dynasties, it was further recognized that the onset of the disease was related to the lack of qi and blood after strain. It is written in the “Secret Formula of the Immortal for the Treatment of Injuries” that “the pain in the shoulder and back is caused by injuries to the tendons and bones”. This pointed out that it was clearly related to trauma. In the Qing Dynasty, the “Jinjian of Medicine” summarized the knowledge of shoulder and arm pain for thousands of years and pointed out that shoulder and back pain has symptoms such as meridian qi stagnation, qi deficiency, blood deficiency, and concurrent wind and phlegm. 3. Pathology The lesions around the shoulder joint mainly occur around the glenohumeral joint, which includes: (1) muscles and tendons. They can be divided into two layers. The outer layer is the deltoid muscle and the inner layer is the four short muscles of the supraspinatus, infraspinatus, subscapularis and lesser round muscle and their joint tendons. The joint tendons are closely connected to the joint capsule and are attached to the upper end of the humerus like a cuff, called the rotator cuff or rotator cuff. The rotator cuff is one of the most stressed structures during shoulder joint movement and is easily damaged. The long tendon of the biceps muscle starts above the articular labrum and passes through the bone fiber tunnel in the intertrochanteric groove of the humeral tuberosity, which is the site of inflammation. The short head of the biceps muscle begins at the rostral process and travels anteriorly through the glenohumeral joint to the upper arm, where the muscle spasms when affected by inflammation, affecting shoulder abduction and posterior extension. (2) Bursa. There are subdeltoid bursa, subacromial bursa and rostral subacromial bursa. The inflammation may interact with the adjacent deltoid, supraspinatus tendon, and short biceps tendon. (3) Articular capsule. The glenohumeral joint capsule is large and loose, and the shoulder has a large range of motion and is therefore vulnerable to injury. Chronic injury to these structures is characterized by hyperplasia, roughness, and intra- and extra-articular adhesions, resulting in pain and functional limitation. In the later stages, the adhesions become very tight and even adhere to the periosteum, at which point the pain disappears but the functional impairment is difficult to restore.