Frozen shoulder mostly develops unilaterally, more often on the left side than on the right side, and in a few patients it can develop bilaterally at the same time. The age of onset of frozen shoulder is consistent with the age of severe degeneration of the shoulder joint, and there is a history of injury to the shoulder or a history of local external fixation, cold, or hemiplegia, or the onset of the disease without any cause. The main symptoms are shoulder joint pain, muscle weakness, and impaired movement. The most obvious symptom is pain, which varies greatly in degree and nature, and may be dull or cut-like, with persistence. The pain and muscle spasm can be limited to the shoulder joint, but can also radiate upward to the back of the head, downward to the wrist and fingers, or backward to the scapula and forward to the chest; some radiate to the triceps muscle or to the deltoid and biceps muscles to the radial side of the forearm. The location of the pressure point and the degree of pressure pain are also inconsistent depending on the stage of the disease. In addition, the diagnosis of diseases related to this disease can be differentiated according to the location of muscle pain and pressure caused by muscle spasm. For example, pain and pressure in the left thoracic muscles should be considered for the diagnosis of cervical spine disorders. The degree of impaired shoulder joint movement varies from one stage of the disease to another and can range from mild dysfunction to complete loss of joint movement. According to the occurrence and development of frozen shoulder, it can be roughly divided into 3 phases, namely, acute phase, chronic phase, and recovery phase. There are no obvious boundaries between the phases, and the length of each phase varies greatly from person to person. 1. Acute stage: This is the early stage of frozen shoulder. The pain in the shoulder is spontaneous, often persistent, and the performance varies. Some of the pain is acute, but most of it is chronic, and some of it is only uncomfortable and binding. The pain is mostly limited to the anterolateral aspect of the shoulder joint and may extend to the point of resistance of the deltoid muscle, often involving the scapular area, upper arm or forearm. The pain is aggravated during activities, such as shrugging or internal rotation of the shoulder while wearing a shirt, and it is not possible to comb the hair or wash the face. Later, the shoulder pain increases rapidly, especially at night, and the patient does not dare to lie on the affected side. Due to the muscle spasm and pain, the range of motion of the shoulder joint is gradually reduced, especially the limitation of abduction and external rotation is most significant. The appearance of the shoulder is normal. The local pressure points are mostly located in the inter-nodal groove and rostral process. The subacromial bursa or deltoid muscle attachment, supraspinatus muscle attachment, and intra-suprascapular angle. 2. Chronic phase: Shoulder pain gradually decreases or disappears, but the contracture and stiffness of the shoulder joint gradually increases in a frozen state. The shoulder joint activity in all directions is 50%-20% less than normal. In severe cases, the shoulder-humeral joint activity disappears completely, and only the scapulothoracic joint activity is present. It is difficult to comb the hair, put on clothes, lift the arm, and knot the belt backwards. Mild muscle atrophy may occur in long-standing cases, mostly in the deltoid and scapular muscles. The pressure pain is mild or non-existent, but it lasts for a long time, usually 2-3 months. 3.Recovery period: Shoulder pain basically disappears, individual patients may have slight pain. The shoulder joint slowly relaxes, and the movement of the joint gradually increases, with external rotation returning first, followed by abduction and internal rotation. The length of the recovery period is related to the duration of the acute and chronic phases. The longer the freezing period, the slower the recovery period; the shorter the duration of the disease, the faster the recovery. The entire course of the disease can be as short as 1 to 2 months, and the onset can be several years.