Chiari malformation is a condition in which the brain tissues extend or herniates into the spinal canal. It can happen when the posterior fossa (a space in the skull that has cerebellum, a part of brain) is smaller than usual pressing the brain downwards.
They are categorized into four categories- Type 1, Type 2, Type 3 and Type 4. Type 1 Chiari malformation develops as the skull and brain develop while Type 2,3 and 4 Chiari malformations are congenial, present by birth.
