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Chiari malformation type 2

Other Names for this Disease
  • Arnold Chiari malformation type II
  • Arnold-Chiari malformation
  • Chiari malformation type II
  • Chiari type II malformation
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Chiari malformation type 2 (CM type II) is a type of Chiari malformation in which both the cerebellum and brain stem tissue extend into the foramen magnum (the hole at the skull base for passing of the spinal cord).[1] This form is often accompanied by a type of spina bifida called myelomeningocele, and can also be accompanied by syringomyelia, hydrocephalus, or other abnormalities.[2] Symptoms in infants may include stridor (wheezing sound); difficulty swallowing (dysphagia); feeding difficulties; hypotonia; and weak cry.[3] Symptoms in children and/or adults may include headache; fatigue; loss of vision; tingling extremities; nausea; dysphagia; dizziness; muscle weakness; and ataxia. Adults and adolescents who previously had no symptoms may begin to have symptoms later in life.[2] The exact cause of the condition is not known but it appears to be due to a developmental failure of the brain stem and upper spine.[2] The term Arnold-Chiari malformation is technically specific to type II but may sometimes be used to describe other types of Chiari malformations.[1]
Last updated: 8/8/2011


  1. Chiari Malformation Fact Sheet. NINDS. June 7, 2011; Accessed 8/8/2011.
  2. Arnold-Chiari Malformation. NORD. April 19, 2008; Accessed 8/8/2011.
  3. Cassandra L. Kniffin. CHIARI MALFORMATION TYPE II. OMIM. August 9, 2006; Accessed 8/8/2011.
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  • The Online Mendelian Inheritance in Man (OMIM) is an catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
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