How many people have Chiari?
There is no exact answer to this, because a rigorous study to determine this has not been performed. Once thought to be rare, the increased use of MRI’s has shown that Chiari is much more common than originally believed. Confusing the issue is the question of how you define Chiari. Many people may have cerebellar tonsils that descend out of the skull, but they have no symptoms and probably never will. Studies have shown the incidence of this tonsillar ectopia may be as high as .5%-.7% of the general population. However, this does not mean that all these people have Chiari. Estimates for the number of people with true Chiari range as high as 500,000 in the United States. A more conservative estimate of 300,000 would mean that 1 in 1,000 people have Chiari, or 0.1% of the population. Return To Top.
