Vanessa,
TOS stands for Thoracic Outlet Syndrome. Just go down to the bottom and go to the area where you pulled up the RSD website and scroll down until you come to the Thoracic Outlet Syndrome site.

I am not a good explainer of TOS, I just live with it. I've always been one to say next to the RSD it's the second syndrome closest to hell.

It is nerve impingement in the thoracic area. I have had a rib removed on the right side to make room for the nerves to spread. There are 3 kinds of TOS and luckily I only have the neurological. There is definatly no cure. Surgery only sometimes helps. The surgery can also bring on RSD. That's how I ended up with the RSD.

There are a lot of good people over there and they will help you with any answers you might need on it.

Sorry I'm not much help but as I said I live with it but I can't explain any of it. LOL

Ada