Re: numbness in thumb, index, midle and ring finger.
Each part of your cervical spine actually represents or flows through the fingers (the nerves). Doctors thought I was having a CTS flareup after shoulder surgery, turns out that it was not in fact the problem it was c4-c7 being herniated with c6-c7 crushing the nerves.
I had found a website once explaining which one related to which but can't find it now. I know that pain outside the hand is usually c4, numbness in index and middle usually represent c6 and c7.
Often times folks can be misdiagnosed with CTS when it's really a nerve being inpinged in the neck. Usually you know within months that it is the neck as the numbness stays and pain starts raidating down the arm, shoulder and across the back as well as the neck.