The tendon sheath is a normal tissue structure of the human body, which is a double-layer casing-like dense synovial canal around the tendon, the inner layer is attached to the surface of the tendon, and the outer layer is lined inside the tendon fiber sheath, which has the function of fixing, protecting and lubricating the tendon from friction and compression. When the hand is fixed in a certain position for repetitive and excessive activities, friction between the tendon and tendon sheath often occurs, resulting in edema, fibrous changes, and thickening of the sheath wall, causing narrowing of the inner lumen. As the tendon moves through the narrowed tendon sheath, it causes pain and movement disorders, which is called tenosynovitis, also known as stenosing tenosynovitis. The common clinical examples are radial tuberosity stenosing tenosynovitis and finger flexor tendon stenosing tenosynovitis. 1, radial stem stenosing tenosynovitis The long thumb extension and short thumb extension tendons may become inflamed below the supporting band of the slide in the radial stem region (i.e., the thumb side of the wrist) and become painful, especially when flexing to the little finger side (i.e., the ulnar side); for example, when picking up a baby or lifting a heavier object. Early management focuses on braking, preventing lateral movement of the wrist joint, and controlling the movement of the carpometacarpal joint, or metacarpophalangeal joint. If conservative treatment is not effective, surgical treatment should be chosen. 2, finger flexor tendon sheath stenosis tenosynovitis Treatment as above, when the pain is more severe and the symptoms of compression are more severe, surgery can be considered.