Medical Dictionary

Chiari malformation

noun Chi·ari malformation \kē-ˈär-ē-\

Medical Definition of Chiari malformation

  1. :  a congenital abnormality of the hindbrain in which the cerebellum and often parts of the brain stem protrude into the spinal canal through the foramen magnum Blocked spinal fluid can cause hydrocephalus or, as is more common in Chiari malformation, a fluid-filled cyst known as a syrinx.—Rebecca Voelker, The Journal of the American Medical Association, 14 Jan. 2009 Chiari malformation is usually classified into four types. Type 1 involves protrusion only of the lower part of the cerebellum into the spinal canal and is often asymptomatic. Type 2 is the Arnold-Chiari malformation. In type 3, the cerebellum is completely displaced into the spinal canal. In type 4, the cerebellum fails to develop completely.

Biographical Note for chiari malformation




(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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