Chiari I
herniation of medulla + cerebellar tonsils
· 4th ventricle in normal position
Chiari II
herniation of medulla, tonsils, vermis
· 4th ventricle at foramen magnum
· towering cerebellum
· tectal beaking
· myelomeningocele
· aqueductal stenosis ==> hydrocephalus
Chiari III
further herniation
· 4th ventricle below foramen magnum
associated with:
The above case is Arnold Chiari Malformation Type I