The sensory system of the fingers is distributed to the hand and fingers through the spinal nerves along the arm. If there is damage or inflammation in these areas, it can cause numbness in the fingers. Numbness in the index finger may be caused by insufficient blood supply to the nerves in the hand, damage to the radial nerve, or compression by cervical spondylosis. 1, inadequate blood supply to the hand nerve: body posture or finger placement is not correct, it is easy to cause the arm and hand blood supply disorders, resulting in insufficient blood supply caused by numbness in the index finger. In addition, if the arm suffers from a tumor or serious injury and compression, will also cause numbness in the index finger. 2, cervical spondylosis: due to poor living habits, more and more patients with cervical spondylosis, lighter patients will often feel numbness in the fingers and arms; serious patients will feel very numb and painful in the shoulder and arm area, and even the difficulty of holding things. 3, radial nerve damage: the radial nerve of the arm is more prone to injury, resulting in numbness and pain in the back of the index finger. 4, neuritis: neuritis in the hand can cause numbness in the index finger. In summary, if there is a long period of numbness symptoms, and more and more serious, you must seek timely medical attention. To be treated according to the examination, do not blindly use drugs.