The tendon sheath is a sheath-like structure that surrounds the tendon. The outer layer is a fibrous tissue that attaches to the bone and adjacent tissues and serves to anchor and protect the tendon. The inner layer is synovial membrane that nourishes the tendon and secretes synovial fluid to facilitate the gliding of the tendon. Repeated excessive friction causes inflammation, edema, and thickening of the fibrous sheath wall of the tendon and tendon sheath to form a narrow ring, and the fibrosis and thickening of the tendon causes difficulty in sliding the tendon within the sheath, which is called stenosing tenosynovitis. Tenosynovitis occurs mostly in the thumb and middle finger. The affected finger may have dysfunction in flexion and extension, which is particularly noticeable in the early morning when waking up, and can be reduced or disappeared after activity. Sometimes a nodule the size of a pea may be palpable in the affected finger. The pain sometimes radiates to the wrist, and there may be pressure pain in the metacarpophalangeal joint in flexion. When bending the affected finger, the finger can be suddenly stuck in a semi-bending position, neither straightening nor bending, and the pain is unbearable, and when the other hand is used to assist in triggering, the finger can move again, producing a trigger-like action and popping sound, so it is also called “trigger finger” or “popping finger”. The finger is also called “trigger finger” or “popping finger”. The following measures can be taken for treatment: 1, reduce the activities of the finger at an early stage, so that the local rest; 2, massage, acupuncture has a certain effect; 3, hydrocortisone acetate, trenbolone acetate or prednisolone acetate injected into the tendon sheath, local injection, the efficacy is better; 4, the disease is long, recurrent, the above treatment is not effective, can cut the narrow part of the tendon sheath, parallel partial excision, so that the tendon sheath no longer squeeze tendon, in order to achieve the purpose of radical treatment. Tenosynovitis can recur after a period of time. In order to prevent the recurrence of tendinitis, attention should be paid to removing the causes of tendinitis, including moderate engagement in activities that tend to cause tendinitis, such as hand-knitting sweaters and knotting joints for women, and changing incorrect lifestyles, such as using the keyboard on the computer for too long or sending too many text messages on the cell phone. Avoid prolonged contact with cold water. Regular hand exercises are also important to prevent the recurrence of tenosynovitis.