Arnold-Chiari malformation

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
• hypo/agenesis of corpus callosum, colpocephally
• luckenschadel skull

Chiari III

further herniation

• 4th ventricle below foramen magnum
• encephalocele or myelomeningocele

• syrinx

© 2002, C.E. Kahn, Jr.
2002-04-18