Arnold-Chiari malformation classification

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Fahimeh Shojaei, M.D.

Overview

Arnold chiari malformation may be classified according to herniation content into 4 subtypes. Type 1 has herniation of cerebellar tonsils. Type 2 has herniation of cerebellar tonsils and vermis. Type 3 has herniation of cerebellar tonsil and vermis and lower brain stem. Type 4 has cerebellar hypoplasia with brain stem in posterior fossa.

Classification

Arnold chiari malformation may be classified according to herniation content into 4 subtypes:^[1]

Subtypes	Explanation	Association
Type1	Herniation parts: Cerebellar tonsils	Syringomyelia
Type 2	Herniation parts: Cerebellar tonsils and vermis	Lumbosacral myelomeningocele
Type 3	Herniation parts: Cerebellar tonsil and vermis, lower brain stem	Occipital encephalocele
Type 4	Herniation parts: Brain stem located in posterior fossa, underdeveloped cerebellum	A variation of cerebellar hypoplasia

Syringomiyelia associated with Chiari malformation

References

↑ Cotes C, Bonfante E, Lazor J, Jadhav S, Caldas M, Swischuk L, Riascos R (June 2015). “Congenital basis of posterior fossa anomalies”. Neuroradiol J. 28 (3): 238–53. doi:10.1177/1971400915576665. PMC 4757284. PMID 26246090.

Overview