Arnold-Chiari Malformation

• common malformation during neurological development, involving the displacement of the cerebellum, medulla, pons and 4th ventricle below the foramen magnum of the skull
  • due to a small posterior fossa - structures too large to fit and therefore will herniate through
• May present with hydrocephalus
• Frequently associated with myelomeningocele
• Lesser degrees are compatible with survival in adults
• Associated with other malformations
• Maybe associated with mental retardation of cerebral palsy