Portions of the cerebellum protrude through the foramen magnum and may compress the brain stem and upper cervical cord
The lower end of the cord has an abnormal attachment to surrounding structures, stretching and damaging the spinal cord
Chiari malformation is often accompanied by syringomyelia, where CSF is located abnormally within the spinal cord
Cyst or cavity formed within the spinal cord
Type I ChiariThe cerebellar tonsils are herniated through the foramen magnum
The tonsils, vermis, 4th ventricle, Pons, and medulla are displaced caudally through the foramen magnum. The cerebellar vermis is a narrow, wormlike structure between the hemispheres of the cerebellum
Defect in the back of the head or neck through which the cerebellum and/or brainstem is herniated
Usually, they do not survive past infancy