Arnold-Chiari type II malformation

A type of Chiari malformation that consists of brainstem herniation and a towering cerebellum in addition to the herniated cerebellar tonsils and vermis due to an open distal spinal dysraphism/myelomeningocele. While Chiari I malformation is thought to result from a small posterior fossa, Chiari II occurs due to in utero malformation of the spine and cranial structures. The underlying cause of Chiari II malformation is thought to be an in utero CSF leak due to open spinal dysraphism, resulting in a small posterior fossa with distortion of the cerebellum and a diminutive cisterna magna, sometimes accompanied by ventriculomegaly and an altered shape of the calvarium. Chiari II malformation is always associated with spinal myelomeningocele or myelocele. Classical signs described on prenatal ultrasound include lemon sign and banana cerebellum sign.

http://purl.obolibrary.org/obo/HP_0025660

While Chiari I malformation is thought to result from a small posterior fossa, Chiari II occurs due to in utero malformation of the spine and cranial structures. The underlying cause of Chiari II malformation is thought to be an in utero CSF leak due to open spinal dysraphism, resulting in a small posterior fossa with distortion of the cerebellum and a diminutive cisterna magna, sometimes accompanied by ventriculomegaly and an altered shape of the calvarium. Chiari II malformation is always associated with spinal myelomeningocele or myelocele. Classical signs described on prenatal ultrasound include lemon sign and banana cerebellum sign.

https://orcid.org/0000-0002-0736-9199

A type of Chiari malformation that consists of brainstem herniation and a towering cerebellum in addition to the herniated cerebellar tonsils and vermis due to an open distal spinal dysraphism/myelomeningocele.

Arnold-Chiari type II malformation

Chiari type II malformation

HP:0025660

Chiari type II malformation

http://purl.obolibrary.org/obo/HP_0002308