The tendon sheath is a sheath-like structure that surrounds the tendon. The outer layer is fibrous tissue, attached to the bone and adjacent tissues, playing a role in fixing and protecting the tendon. The inner layer of synovium can nourish the tendon and secrete synovial fluid to facilitate the sliding of the tendon due to repeated excessive friction, causing inflammation of the tendon and tendon sheath, edema, thickening of the wall of the fibrous sheath to form a narrow ring, the fibrosis of the tendon and thickening of the tendon caused by the tendon in the sheath tube sliding difficulties, which is the stenosis of tenosynovitis. Stenosing tenosynovitis is a tendon of the flexor digitorum and flexor digitorum, and the site of stenosis is on the palmar side of the metacarpal neck. The other site is tenosynovitis at the radial tuberosity, where the short extensor tendon and the long extensor tendon are located in the same sheath, causing pain in the affected area and tenderness when the fist is held in the ulnar deviation of the wrist. Treatment of tenosynovitis: heat therapy, massage and adequate rest for about 3 weeks, especially to reduce the manual labor that causes the disease. Localized closure treatment, can make the early tendinitis get relief, once a week closure. If the above treatment is ineffective or recurrent, tenosynovotomy should be performed, and after the operation, early finger flexion and extension activities should be done to prevent tendon adhesion. Free from manual labor for 1 month after the operation, and pay attention to the rest of the affected area. Since tenosynovitis is an inflammation caused by repeated excessive friction, it is important to avoid excessive manual labor for those who have suffered from this disease.