Arnold-Chiari malformation

Arnold-Chiari malformation

[är′nəldkē·är′ē]

Etymology: Julius Arnold, German pathologist, 1835-1915; Hans Chiari, French pathologist, 1851-1916

a congenital herniation of the brainstem and lower cerebellum through the foramen magnum into the cervical vertebral canal. It is often associated with meningocele and spina bifida. See also neural tube defect.

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Arnold-Chiari malformation

a congenital anomaly in which the cerebellum and medulla oblongata protrude down into the cervical spinal canal through the foramen magnum; it is almost always associated with meningomyelocele, spina bifida and hydrocephalus. Recorded in calves, sheep and dogs.

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Arnold-Chiari malformation

Neurology A congenital compression deformity of the 'lower brain' characterized by herniation of the cerebellar tonsils and distal medulla oblongata through the foramen magnum into the spinal canal; ACM is accompanied by compression of the 4^th ventricle and firm adhesions at the cisterna magna