The movement of human joints is achieved by muscle contraction and tendon traction, and tendons must generally pass through more than one joint. When a tendon passes around a joint or a bony bulge, the deep fascia thickens into a ring or a wide flat support band to hold the tendon in place in order to avoid slippage of the tense tendon. For example, the dorsal carpal ligament in the wrist and the sphincter ligament in the fingers. Since the tendons are prone to friction when passing over the bony bulge and joints, they are protected by tendon sheaths and synovial sheaths (which act as a lubricant) in these areas. However, if there is excessive friction, tendon tendinitis can occur. Tenosynovitis and tendon sheath cysts are very common, accounting for about 16% of sports injuries, with tenosynovitis in the hand and wrist, especially in the thumb flexor tendon, finger extension and wrist extension tendons, being the most common. Its occurrence is closely related to local overwork. The main pathological changes are tendon sheath hypertrophy, inelasticity, and tight compression of the tendon. Sometimes the tendon becomes thin in the narrow part of the tendon sheath, its ends are edematous, and in time the tendon can become hypertrophic and pike shaped. Pathological section examination all show chronic inflammatory changes. I. Tenosynovitis of the radial styloid process (De Quervain’s disease) The general tendon sheath of the short extensor digitorum longus and extensor digitorum longus is the most common site of tenosynovitis. Any kind of movement of the wrist can cause injury to this area after overexertion. Bunnell has said that when the wrist is dorsally extended and tilted to the radial side with force (such as when holding a tennis racket), the tendons of the two muscles can be worn down and tendinitis can occur. ), the biceps tendon takes a 105° turn at the stem, causing the tendon sheath and tendon to rub against each other when the thumb and wrist move, resulting in injury. Most of the patients presented with complaints of pain around the wrist or thumb and limited movement of the thumb. Some of these patients specify pain at the radial styloid process. In mild cases, the pain is localized to the thumb when the thumb is moved. In severe cases, the pain often spreads to the forearm and shoulder, severely affecting work and sleep. Clinical examination: Mild swelling is sometimes found in the radial styloid process, with sharp localized pressure pain and tendon sheath hypertrophy. Patients with acute symptoms and the onset of the disease does not exceed one month can try conservative treatment. Such as braking, oral anti-inflammatory and analgesic drugs, local closure, physical therapy, etc. In recent years, local injections of prednisolone drugs have been widely used with good results. During conservative treatment, the wrist activity should be temporarily restricted (2 weeks of brace braking is effective). Surgery should be considered when conservative therapy is ineffective. The tendon sheaths of the thumb flexors and finger flexors are the most common in the general public. The tendon of the long flexor thumb enters a narrow canal formed by the bony groove and sheath ligament on the palmar side of the metacarpal at the neck of the first metacarpal. At the base of the first phalanx and its ulnar side of the seed bone, the superficial and deep heads of the thumb flexor are attached, respectively, and the tendon of the long thumb flexor passes between them. Because this section of the tendon sheath is narrow, it is easily worn down and subject to tenosynovitis. The tendons of the superficial flexors and deep flexors of the other four fingers travel to the metacarpal neck, and the two tendons are squeezed into a narrow tendon sheath surrounded by bone and ligaments, and the two tendons rub against the tendon sheath for a long time, causing chronic inflammation. The main symptom is pain and limited pressure when moving the finger. Some patients complain of swelling and pain in the interphalangeal joint because the interphalangeal joint cannot be straightened and moved normally. Some patients complain of swelling and pain in the interphalangeal joint because the interphalangeal joint cannot be straightened and when the finger is straightened by moving the flexed finger, the pain is also obvious on the palmar side of the metacarpal head, and there is often a “popping sound”, so it is also called “trigger finger”. There is sharp, limited pressure pain on the palmar side of the metacarpophalangeal joint, and sometimes small nodules can be palpated in this area due to tendon hypertrophy. Patients with acute symptoms and an onset of less than one month can be treated conservatively. Such as braking, oral anti-inflammatory and pain-relieving drugs, local closure, physical therapy, etc. Surgery should be considered when conservative therapy is not effective. Tendon sheath cyst This disease is a cyst that occurs inside the joint capsule or tendon sheath. It is common in the wrist, and can occur on the palmar and dorsal side of the wrist, with the dorsal side of the wrist being the most common site of predilection. The cysts are often unicompartmental and vary in size and contain clarified jelly-like fluid in the compartment. The cause of the disease is unclear. Patients have localized masses that are not adherent to the skin, smooth in shape, full to palpation, sometimes volatile to feel, and sometimes hard as cartilage. It occurs gradually with enlargement, but there is variation in size. Generally, it is only mildly sore and swollen and has a mild effect on joint movement. If it is connected to the tendon sheath, finger weakness may be felt. If the cyst is shallow, the patient can often squeeze it by himself, and with appropriate local massage, it can heal itself. However, it can recur. If it is asymptomatic and does not affect the function of the joint, surgical treatment is not usually used. On the contrary, surgical treatment will remove it, but it can recur after surgery.