Author Topic: Chiari Zero or Chiari 0  (Read 1049 times)

Ryan Ryder

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Chiari Zero or Chiari 0
« on: August 23, 2015, 11:27:12 PM »

Currently, there are five types of Chiari malformations or cerebellar tonsillar ectopia based on the degree of descent of the cerebellum and braintem, as well as other factors such as congenital defects in the brain, cord and spine, which will be discussed below.

They range from a Chiari 0 malformation, with minimal tonsillar etopia (displacement) and herniation into the foramen magnum, to a Chiari 4 with significant tonsillar ectopia and herniation and other problems. The greater the degree of downward displacement the more likely it is to involve other parts of the brainstem along with the cerebellum.


Chiari Malformations are typically graded according to the depth of penetration of the brainstem into the foramen magnum.

A new term has been coined however, called Chiari 0. In a Chiari 0 the brainstem does not sink into the foramen magnum. Instead, the space typically filled with fluid between the bottom of the cerebellum and base of the skull gets compressed.


Chiari isn't always a problem. Some people have large malformations (deep descent) and little or no symptoms and some people have mimimal descent, referred to as Chiari 1 or Chiari 0, with major problems.

The issue with all Chiari type malformations, though, is that they have the potential to compress the components of the brainstem and upper cervical cord in the foramen magnum and upper cervical spinal canal, and because of this, blocking the flow of CSF.

« Last Edit: August 30, 2015, 07:53:56 PM by Ryan Ryder »