so much bad or wrong information about Arnold Chiari Malformation ACM1

I've been reading some of the answers given about Chiari Malformation, and forgive me please but as of 2006, much more is known about this.  I'm reading people about some extreme neurological issues, and they're told their problem isn't consistent with their Chiari Malformation!? To paraphrase Thomas Milhorat, it isn't the size of the herniation of the tonsils, but the lack of CSF space that causes your problems.  So, yes, it is correct that you can have an "11 mm herniation and be asymptomatic", but you can have a 1mm herniation and be VERY symptomatic!!  

I'm suprised.  Please learn about the Chiari Institute,
http://www.northshorelij.com/body.cfm?id=6456&oTopID=6456&PLinkID=6407

and watch Dr. Bolognese in the videos.  You'll be amazed at how many neuro. issues can be created/exacerbated by the seemingly innocent Chiari Malformation.  Every person presents a little differently.  They do decompression surgey using doppler flowmetry(?), measuring the CSF flow improvement DURING the surgical process.  Do NOT have decompression anywhere else--they do more surgeries than anyone in the world, and fix other BOTCH jobs.  

I wish I'd found someone to guide me 5+ yrs ago when my symptoms started.  To this day, I have 'big name' "neuro institutes" NOT recognizing my ACM1! I feel BLESSED to have found the Chiari Institute (Great Neck NY)--send them your recent MRI/report and if they think they can help or want to evaluate you, they'll make an appt for you. I've never felt so medically VALIDATED in my life.

ALso, read Dr. Milhorat's study..."Chiari Redefined".  
good luck