It is common to see this phenomenon in daily outpatient clinics. Patients who present to the doctor with shoulder pain and limited range of motion, especially when it is difficult to raise the arm, think they have frozen shoulder. In fact, this is due to the fact that there is still a large misunderstanding of shoulder disorders. According to the American Sports Medicine Association, frozen shoulder is actually an adhesive capsulitis, which is a self-limiting disease. The incidence of true frozen shoulder is relatively low, and rotator cuff injuries are the most prevalent shoulder disorders, followed by acromioclavicular impingement and shoulder instability. It is clear that sometimes in life, even orthopedic surgeons who are not trained in shoulder disorders may have the same misconceptions as laymen. Some patients may therefore delay treatment, which may even lead to functional disability of the shoulder joint and seriously affect their daily life. How to get out of the misunderstanding of frozen shoulder? The first step is to understand the structure of the shoulder joint from an anatomical point of view. The shoulder joint is composed of the humeral head and the scapular glenoid. The humeral head is large while the scapular glenoid fossa is shallow, and the surrounding joint capsule is relatively weak, so the shoulder joint is the most mobile and flexible joint in the body. There are tendons or ligaments that wrap around the humeral head from the front, top and back of the shoulder joint to enhance the stability of the shoulder joint, and this tendon structure is called the rotator cuff tissue. An articular bursa covers the rotator cuff to reduce impingement friction between the rotator cuff and the rostral shoulder arch above it. Because of the high mobility of the shoulder joint, there exists an anatomical basis for susceptibility to shoulder joint disease. Second, we need to properly understand shoulder disorders. Statistically, the highest incidence of shoulder disorders is rotator cuff injury, which accounts for 30-40% of shoulder disorders. Rotator cuff injury is a very common degenerative disease of the shoulder joint, and its occurrence is positively correlated with age. The symptoms of rotator cuff tear are similar to those of subacromial impingement syndrome, but they are also accompanied by shoulder abduction weakness. Athletes, those who lift heavy objects, and those who suffer from traumatic injuries are prone to rotator cuff injuries. The typical symptoms are pain in the neck and shoulder at night and pain in the upper arm; sometimes they are afraid to sleep on the affected side and may even wake up with pain. In the case of acromioclavicular impingement, the acromion and subacromial bursa tissues collide with rotator cuff tissues during shoulder abduction and supination, resulting in shoulder pain and supination dysfunction. The third most prevalent shoulder disorder is shoulder instability. Due to trauma or degeneration of the joint structure, as well as the high mobility and relatively poor stability of the shoulder joint itself, the shoulder joint is prone to dislocation or subluxation. The affected shoulder will produce pain, impaired movement, limited function, and in some cases, habitual shoulder dislocation. If left untreated, bone defects and joint surface destruction can occur, making later treatment difficult and in some cases even tricky. Frozen shoulder, in essence, is adhesive capsulitis. It is a condition in which the soft tissues of the shoulder joint, including muscles, tendons, ligaments and joint capsule, become congested and edematous. If your arm is painful when you extend it forward, backward, upward, outward, or rotate it inside or outside, and if you are unable to do so because of pain when combing your hair and washing your face, rubbing your back in the shower, or grabbing the handrail when riding in a car, you may have frozen shoulder. Frozen shoulder mostly develops unilaterally, with the left side being more common than the right side. 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. Pain is the most obvious symptom, and the degree and nature of pain varies widely, ranging from dull pain to cutting pain, which can be persistent. Recent medical research has found that periarthritis of the shoulder is not a completely isolated disease, it may be a special manifestation of certain underlying diseases, such as diabetes, cervical spondylosis, coronary heart disease, lung cancer, etc., so it should be alerted. According to foreign studies on diabetic patients, periarthritis is indeed associated with high diabetes, and many diabetic patients suffer from periarthritis. Other studies have also found that a high percentage of patients with periarthritis have diabetes. The relationship between periarthritis and cervical spondylosis is even closer. In cervical spondylosis, the hyperplastic bone compresses the sympathetic fibers in the anterior cervical nerve root. This chronic irritation alters the blood supply to the shoulder joint and its surrounding tissues, leading to atrophic changes in the shoulder joint. Also, the irritation of the compressed cervical nerve root can cause shoulder involvement pain and reduce its movement. Among lung cancer patients, there are sometimes shoulder pain as the first symptom, but this kind of shoulder pain has its own characteristics: although the pain is severe, it is usually not accompanied by obvious upper limb movement disorder, and no pressure point can be found in the shoulder. It is worth mentioning that the diagnosis of frozen shoulder relies on medical infrared thermography, which is convenient, simple, fast and visual, objective and accurate, painless and non-invasive. With the thermogram of the shoulder joint and its surrounding soft tissues (thermogram for short), it is not difficult to diagnose through complaints, signs, and laboratory tests, and to take effective targeted treatment through the thermogram and evaluate the efficacy of multiple thermogram comparisons. Frozen shoulder treatment aims to improve blood circulation in the shoulder, enhance metabolism, reduce muscle spasm, stretch adhesions and contractures of the tissues in order to reduce and eliminate pain and restore normal function of the shoulder joint. In the acute stage or early stage, it is best to take some fixation and analgesic measures to relieve the patient’s pain, such as suspension with a triangular scarf, and to apply heat to the shoulder, physiotherapy, nerve block, intra-articular injection (drugs or ozone), etc. In the chronic stage, the main manifestation is shoulder joint dysfunction. At this time, the treatment is based on loosening the adhesive tendons and ligaments of the shoulder (such as acupuncture, medicine knife, heat-conducting silver needle) and functional exercise, together with physiotherapy. Frozen shoulder usually has a long course, especially if the shoulder joint function is limited, the time can be extended to several months or even a year. Therefore, elderly people with frozen shoulder should insist on daily rehabilitation exercises and gradually increase the time and number of exercises in order to achieve better results. Exercise should be done to cause mild pain, but should avoid causing severe pain. Frozen shoulder can be prevented. Older people generally lack activity, and the blood circulation in the upper limbs and tissues around the shoulder is poor. Therefore, the joint capsule and tendons of the shoulder joint are prone to degeneration, calcification and inflammation. If elderly people usually pay attention to exercise and exercise their upper limbs and shoulders, they can effectively avoid the occurrence of frozen shoulder.