Chiari Malformations (CM) are rare structural defects in the cerebellum (the structure located at the back of the brain). Normally, the cerebellum sits on the indented space below the skull. However, the cerebellums of patients with chiari malformations sit lower than they should. CMs may develop when the skull is smaller than normal, causing the cerebellum and brain stem to be pushed down into the spinal canal. This results in pressure on the cerebellum and brain stem, which may affect functions controlled by these areas.
