Numbness of the index finger is considered to be related to cervical spondylosis, brachial plexus nerve injury, carpal tunnel syndrome and other diseases. 1. Cervical spondylosis: If the cervical intervertebral disc protrudes or proliferates, it can compress the nerves and cause numbness of the index finger. 2. Brachial plexus nerve injury: As the fingers are innervated by the peripheral nerves, if the brachial plexus nerve injury, it can cause the blood return obstacle around the fingers and cause numbness, and then lead to numbness of the index finger, and sometimes it can be accompanied by the symptoms of finger swelling and pain. 3. Carpal Tunnel Syndrome: Carpal Tunnel Syndrome is caused by the compression of the median nerve, the median nerve compression will cause numbness of the index finger, the middle finger, the index finger symptoms. There may be other reasons for the numbness of the index finger, and you need to go to the hospital for examination and treatment in time after the symptoms appear, so as not to delay the condition.