Introduction

A Chiari malformation, previously called an Arnold-Chiari malformation, is where the lower part of the brain pushes down into the spinal canal.

There are four main types, but type 1, called Chiari I, is the most common.

In someone with Chiari I, the lowest part of the back of the brain extends into the spinal canal. This can put pressure on the brainstem, spinal cord, and obstruct the flow of fluid.

This page focuses on Chiari I malformations.

Is it serious?

Symptoms

Treatments

Causes

Content supplied by the NHS Website

Medically Reviewed by a doctor on 12 Jul 2016