Stiffness and difficulty in straightening finger joints may be caused by trauma, degenerative changes of finger or interphalangeal joints, rheumatoid arthritis and other reasons. 1. Traumatic injury: the finger is subjected to external force, which may lead to injury of the extensor tendon of the finger, fracture of the finger, injury of the joint capsule of the finger and other injuries, which may lead to stiffness and difficulty in straightening of the finger joints. 2. Degenerative changes of fingers or interphalangeal joints: due to long-term heavy physical labor, the interphalangeal joints of the fingers are prone to bone proliferation, narrowing of the joint space, and contracture of the joint capsule, which cause degenerative changes of the fingers or interphalangeal joints, and the stiffness of finger joints is difficult to extend the symptoms. 3. Rheumatoid arthritis: can cause finger joints, finger joints synovial membrane hyperplasia and swelling, especially in the morning can appear, finger joints stiff and difficult to straighten the performance. Finger joint stiffness and difficult to straighten the situation, but also due to other factors, need to go to the regular hospital as soon as possible for examination and treatment.