Fingertip flexion may be related to trauma, arthritis, and prolonged exertion. Trauma to the hand may cause rupture of the tendon joint capsule, and in severe cases, fracture of the finger bones, and then the symptoms of not being able to straighten the fingertips will occur, accompanied by pain, swelling and other symptoms. Rheumatoid rheumatoid arthritis, gouty arthritis, osteoarthritis and other diseases invade the finger joints, in the late stage of the lesion will also appear to be unable to straighten the phenomenon. Engaging in manual labor or heavy physical labor for many years may also cause the fingers to bend and deform and not be able to straighten completely. Stenosing tenosynovitis of the flexor tendons of the fingers, when severe, can also result in bent and unstraightened fingertips. Forearm nerve entrapment syndromes such as elbow canal syndrome and carpal tunnel syndrome can also occur in the later stages of the disease when some of the fingers cannot be fully straightened. If you have symptoms that prevent you from straightening your fingers, it is recommended that you go to the hospital and get regular treatment to determine the cause of the problem.