What is chiari malformation and how is it caused?”
It consists of a downward displacement of the cerebellar tonsils and the medulla through the foramen magnum, sometimes causing hydrocephalus as a result of obstruction of cerebrospinal fluid (CSF) outflow . The cerebrospinal fluid outflow being caused by phase difference in outflow and influx of blood in the vasculature of the brain. Terminology Chiari malformation is the most frequently used term for these types of malformations. The use of the term Arnold-Chiari malformation has fallen somewhat out of favor over time, although it is used by some to refer to the type II malformation. Some sources use “Chiari malformation” to describe four specific grades of the condition, reserving the term “Arnold-Chiari” for type II only. Some sources use “Arnold-Chiari” for all four types. This article uses the latter convention. Chiari malformation or Arnold-Chiari malformation should not be confused with Budd-Chiari syndrome, a hepatic condition also named for Hans Chiari. Diagnosis Chiari malfor
