Generally speaking, the pain of the finger can not be flexed and extended is considered to be caused by trauma, rheumatoid arthritis, stenosing tenosynovitis and other reasons. 1. Trauma: such as finger crush injury, impact, sprain, etc., can lead to finger tendon and bone injury, such as phalangeal fracture, etc., can appear abnormal finger movement, deformity, redness, swelling, pain and finger flexion and extension difficulties. 2. Rheumatoid arthritis: an autoimmune disease mainly characterized by erosive arthritis, with the pathological basis of synovitis, which can be expanded to connective tissues such as tendons and finally erode articular cartilage and bone tissues from synovial membrane, resulting in joints being damaged. It may manifest as morning stiffness, swelling, pain and even limited joint movement. Joint involvement is often symmetrical. 3. Stenosing tenosynovitis: It is a common tendon sheath disease, mostly seen in people with more hand labor. There can be morning stiffness and pain in the joints, which disappears after slow activity, and can also cause symptoms such as limited joint movement and numbness. There are many other causes of pain in the fingers, such as arthritis caused by gout. It is recommended to consult a doctor in time to clarify the diagnosis and carry out targeted treatment.