Arnold-Chiari malformation(Type I)

Last reviewed 04/2022

A Type I Arnold-Chiari malformation is characterised by descent of the cerebellar tonsils into the spinal canal. It may be asymptomatic.

In symptomatic patients, it is associated with:

  • spinal diseases - 50% of cases:
    • syringomyelia
    • hydromyelia

  • cranial disorders - 10% of cases:
    • obstructive hydrocephalus