Several common clinical causes of finger flexion and extension. First, it is natural. This is due to the finger bending caused by skeletal muscle dysplasia when I was a child, and I need to go to the hospital for surgical correction later. Second, the fingers are bent and the injury cannot be straightened. Trauma tears ligaments and tendon injuries prevent fingers from bending. This requires going to the hospital to take a photo to confirm the location and degree of the injury, and to carry out drugs or surgery according to the results. Third, tenosynovitis is a common symptom of overuse of keyboard and mouse. In this case, you need to rest and relax more at ordinary times, and keep the correct posture and method when using the mouse. You'd better go to the hospital. Doctors know better.