Medical Dictionary

Arnold–Chiari malformation

noun Ar·nold–Chi·ari malformation \ˈär-nəld-kē-ˈär-ē-\

Medical Definition of Arnold–Chiari malformation

  1. :  a congenital abnormality in which the lower surface of the cerebellum and the lower brain stem protrude into the spinal canal through the foramen magnum She was born with Arnold-Chiari malformation, a rare and random birth defect that occurs, according to one study, in about 8 of 100,000 people. A deformity of the base of the skull and spine, it can cause chronic pain and loss of balance.—Arthur Allen, The Washington Post, 23 Feb. 1997 Arnold-Chiari malformation often occurs with spina bifida and hydrocephalus. It is classified as a type of Chiari malformation.

Biographical Note for arnold–chiari malformation




(1835–1915), German pathologist. In 1866 Arnold was appointed professor of pathological anatomy as well as director of the institute of pathology at the University of Heidelberg. He made significant advances in the development of pathological anatomy, publishing 120 articles in this field as well as in histology. In 1894 Arnold published what was the third description of malformation of the brainstem and cerebellum in children with herniation of the spinal cord. The first description was actually published in 1883 by the Scottish physician John Cleland, but his original contribution was later overlooked or forgotten.




(1851–1916), Austrian pathologist. Chiari served as a professor of pathological anatomy first at the University of Prague and from 1906 at the University of Strasbourg. Most of his research and writings, of which there are more than 177, were the result of his postmortem examinations. In the 1890s he described a condition in children involving deformities of the cerebellum and brainstem, with herniation of the spinal cord. The condition is sometimes associated with his name alone and sometimes jointly with the name of Julius Arnold.

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a rounded knoll or a ridge of ice

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