The shoulder joint is the most mobile joint in the body. It moves in many directions, such as forward, upward, abduction, adduction, and posterior extension. However, with greater mobility, the shoulder is also more susceptible to injury and instability. Certain occupations are also associated with shoulder disorders, such as cleaning walls, hanging curtains, and gardening; swimmers, tennis players, and weightlifters, especially throwers, are prone to shoulder injuries. If shoulder joint injury occurs or shoulder joint pain occurs, the following questions should be noted: l. Is the shoulder joint stiff? Can you rotate your arm normally? 2.Is there a feeling of misalignment of the shoulder joint? 3.Is the shoulder joint weak? If any of the above problems exist, you should go to the hospital for treatment. Normal shoulder joint movement mechanism The shoulder joint is a mortar and pestle joint. It consists of three bones: the upper end of the humerus, the scapula and the clavicle. The head of the humerus and the fossa of the scapula form the glenohumeral joint. The scapula’s socket is surrounded by a layer of soft tissue. The surface of the humeral head is covered with smooth, tough articular cartilage, and there is also a thin synovial membrane in the joint, which reduces friction in the shoulder joint. The part of the shoulder blade that rises anteriorly and superiorly is the acromion. One end of the clavicle is connected to the acromion to form the acromioclavicular joint. The other end of the clavicle attaches to the sternum to form the sternoclavicular joint. The joint capsule is a thin layer of fibers that surrounds the shoulder joint. The presence of the capsule allows for greater mobility and stability of the shoulder joint. The rotator cuff is a group of muscles and tendons that attach to the upper arm and shoulder blade. The rotator cuff covers the shoulder joint and the joint capsule. The rotator cuff is able to raise the arm, feel overhead, and participate in activities such as throwing and swimming. The bursa, which covers the area between the rotator cuff and the shoulder blade, secretes synovial fluid that lubricates during activity. What types of shoulder injuries are most common? Shoulder injuries include areas such as muscles, ligaments and tendons. Shoulder problems are often categorized as follows: Rotator Cuff Injuries More than four million people in the United States seek medical care for shoulder problems each year, and rotator cuff injuries are one of the most common causes in patients over the age of 40. The rotator cuff is the tendon tissue that wraps around the shoulder joint in front of, above, and behind the shoulder joint and stabilizes it. The rotator cuff is able to lift the arm and hold things higher than the top of the head. Trauma and repetitive lifting activities predispose the rotator cuff to injury. After rotator cuff injury, shoulder pain may persist and worsen when doing shoulder lifting activities, which may affect the shoulder function. After rotator cuff injury, it is easy to have muscle weakness, weakness when lifting up the arm; shoulder joint pain at night, especially when lying on the affected side, which seriously affects the sleep at night; friction sensation or popping sound when moving the shoulder joint, and limitation of shoulder joint activities. Shoulder impingement sign The shoulder impingement sign is caused by excessive friction between the rotator cuff and acromion. Impingement problems may occur when frequently involved in an activity that requires lifting the arm. Symptoms are similar to a rotator cuff injury. If not treated properly it may lead to more serious tendon injuries and cause shoulder dysfunction. Shoulder instability A condition called instability occurs when the shoulder joint moves out of its normal position due to activity or force, and in some cases can result in complete misalignment of the shoulder joint. When the shoulder joint is unstable and the arm is raised, the shoulder joint will cause pain and it may also feel like the shoulder joint is slipping out of its normal position. How is a shoulder injury treated? Early diagnosis is the key to avoiding a serious shoulder injury. Treatment for shoulder disorders usually includes non-surgical and surgical treatments. Non-surgical treatments include changes in daily activities, avoidance of overhead arm lifting and active individualized rehabilitation. If the pain is very high or rest and medication are ineffective, subacromial steroid injections can be considered. s8% of patients can be relieved by these injections, but the injections should not be repeated more than once or the rotator cuff will be damaged, and surgery should be considered if the injections are ineffective. Subacromial decompression surgery, if 6 months to a year of conservative treatment is ineffective, or has been combined with the rotator cuff rupture of the patient, it is recommended that surgical treatment, including resection of the rostral acromioclavicular ligament, removal of the anterior and inferior acromial osteophytes. If the rotator cuff is ruptured, repair surgery is also performed. Subacromial decompression is an arthroscopic procedure that is now well established to minimize postoperative discomfort and accelerate recovery. The purpose of the decompression is to thin and flatten the thicker, more curved acromion, so that the rotator cuff is no longer rubbed by the acromion when the upper arm is lifted forward and ligamented. Arthroscopic surgery can be performed with only a few small incisions, and is therefore the treatment of the future. To perform a rotator cuff repair, the ruptured rim is cleaned up and the contractured rotator cuff is loosened and secured tension-free to the greater tuberosity of the humerus. There are various methods of fixation, such as the use of anchor nail fixation. If treatment is delayed, the ruptured residual rotator cuff may have poor M-weave architecture and will re-tear after fixation suturing. Currently, there is an orthopedic trend toward arthroscopic rotator cuff repair, using several small incisions to arthroscopically pin the ruptured tendon to the greater tuberosity of the humerus. Arthroscopic surgery reduces postoperative discomfort and shortens recovery time. Surgical treatment of shoulder instability: Shoulder instability is predominantly anterior to anterior instability, which often injures the glenoid labral ligament complex of the shoulder joint. Shoulder arthroscopy can be used to reconstruct the ligament attachment points, fold or tighten the soft tissues to rebuild the stability of the shoulder joint.