Arnold-Chiari syndrome is a series of nervous system symptoms related to a deformity of the skull.

This condition is often present at birth, but can also develop later in life. Some people with mild forms of this syndrome may never know they have the condition. For others it can be more severe. These severe forms will need treatment.

Arnold-Chiari syndrome is caused by a problem in the back of the skull. The skull should have an indented space in the back of the head. The rear lower part of the brain and the brainstem are in this space. In some people, this indented skull space does not develop well. This is called Chiari malformation. The space inside the skull is too small for the brain. As a result, the brain and brain stem are pushed downward. It blocks the flow of fluid from the brain to the spinal column.

The problem with the skull develops before birth. It is not clear why it happens. In some cases, it occurs with a myelomeningocele, which is a form of spina bifida or syringomyelia, which isfluid cavites in the spinal cord.

Brain Stem and Lower Brain
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