The causes of tenosynovitis can be divided into the following aspects: 1, strain or strain, because after long-term strain, strain, there will be regular friction between the tendon and the tendon sheath, and then inflammation, the tendon sheath will be hyperplastic, and even limited activity, usually called trigger hand. 2, may be cold, because after cold, the local blood vessels, meridians, local inflammation, will also stimulate the inflammation of the tendon sheath, tenosynovitis. The tendon sheath may become inflamed and tendinitis may occur. 3. Some fractures or other tumors may cause local swelling and inflammation of the tendon sheath, causing tendinitis. There are also some drugs, radioactive or rheumatoid arthritis, ankylosing spondylitis, some rheumatic diseases, which can also cause inflammation of the tendon sheath, and gouty arthritis, which stimulates the tendon sheath and causes inflammation of the tendon sheath. Of course, there are also some infectious, such as tuberculosis or some other bacterial, can cause tenosynovitis.