What is the difference between carpal tunnel and arthritis?

Carpal tunnel is the name of the anatomy of your wrist. If you are talking about the actual syndrome, carpal tunnel syndrome, it is caused by compression of the median nerve that runs through the "carpal tunnel" in your wrist. Arthritis is a general term that has to do with inflammation of a joint. This is where the joint surface becomes rough and therefore can cause pain as the 2 joint surfaces can no longer glide over each other.

If someone has arthritis of the wrist bones, this may put them at risk for getting carpal tunnel syndrome because the nerve may have less space in the 'tunnel' and get crowded causing the compression of the median nerve. It is particularly prevalent in the case of rheumatoid arthritis as this is an inflammatory disease and the inflammation put extra pressure on the nerves passing through the carpel tunnel.