Gosh, I don't know why those links don't work, especially when I checked them prior to posting, but they won't work for me now either.

The first link is this this one : http://www.orthogate.org/patient-edu...neck-pain.html

...but sadly I've been unable to get the second link back but I've added these instead.

http://www.ajronline.org/content/178/1/201.long
http://www.nature.com/sc/journal/v44.../3101848a.html
http://www.arscerebri.com/ucsd/usefu...4/13-4-cp1.pdf
http://www.pagepress.org/journals/in....2009.e17/1353

The last 2 might have too much medical jargon for you to understand, but hopefully you'll find something useful in at least one of the links.

My own knowledge of this condition is rather limited, but hopefully some-one else will be able to tell you more.