Chiari malformation is a series of disorders and abnormalities in the development of the brain that occur in the region of the posterior cavity. Usually, patients with Chiari malformation show the first symptoms in adolescence and adulthood. The most common types of Chiari malformation are Chiari malformation type one and two. In people with Chiari malformation, part of the skull is very small; For this reason, there is a lot of pressure on the brain. In some people, the symptoms of this disease are not known at all. In other people, full symptoms are identified and if left untreated, they will have many complications.