I just got a diagnosis. When the doctor told me, I was so nonchalant; however, having done more research, this is rather serious, right? I have seen Chiari support groups, etc., so that got me rather scared. Also, I was reading some of the posts that said that their cerebellar tonsils extended 8 or 10 mm into the foramen magnum. Well, mine says that it's 1 cm. How bad is this? What should I expect?