A Chiari malformation is when brain tissue extends into the spinal cord. It's caused by the skull being misshapen or too small, which pushes brain tissue downward.
There are three types of Chiari malformation:
- Type one happens as the brain and skull grow, and it may not cause symptoms until later in childhood or even in adulthood.
- Types two is present at birth and leads to more brain issue extending into the spinal cord than type one.
- Type three is also present at birth and is the rarest and most serious type of Chiari malformation. In this type, the cerebellum, or brainstem, extends through an opening in the skull.
Treatment for Chiari malformation depends on what type you have and whether you have symptoms. The most common treatment is surgery.