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  • Arnold–Chiari II

  • Arnold–Chiari malformation

  • Chari I malformation

  • Chiari II malformation

  • Tonsillar ectopia

  • Tonsillar herniation




  • 348.4 Compression of brain

  • 742.2 Congenital reduction for deformities of brain




  • G93.5 Compression of brain

  • Q04.8 Other specified congenital malformations of brain

  • Q07.0 Arnold–Chiari syndrome

  • Q07.00 Arnold–Chiari syndrome without spina bifida or hydrocephalus

  • Q07.01 Arnold–Chiari syndrome with spina bifida

  • Q07.02 Arnold–Chiari syndrome with hydrocephalus

  • Q07.03 Arnold–Chiari syndrome with spina bifida and hydrocephalus

FIGURE 233-1

Sagittal T2-weighted MRI scan of a Chiari showing typical peglike appearance of cerebellar tonsils and associated syringomyelia. (From Doherty GM. Current Diagnosis & Treatment: Surgery. 13th ed. Copyright © The McGraw-Hill Companies, Inc. All rights reserved.)

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FIGURE 233-2

Uninfused sagittal T1-weighted (A) and coronal T1 postcontrast (B) imaging in a 30-year-old patient with a Chiari II malformation. (A) A small posterior fossa is present, resulting in cerebellar tonsillar ectopia (long arrow), towering of the cerebellum (short arrow), beaking of the tectum (curved arrow), and compression of the fourth ventricle (arrowhead) with resulting hydrocephalus. Partial agenesis of the rostrum and splenium of the corpus callosum is noted. (B) Cerebellar tonsillar ectopia into the foramen magnum is demonstrated (arrowheads). (From Chen MYM, Pope TL, Ott DJ. Basic Radiology. 2nd ed. Copyright © The McGraw-Hill Companies, Inc. All rights reserved.)

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FIGURE 233-3

(A) Postcontrast coronal T1-weighted images of the brain in a 32-year-old with intractable seizures. An additional circumferential band of gray matter is seen (arrows) deep to the normal gray matter within the occipital region. This finding was noted to be diffusely present throughout the remaining brain parenchyma (not shown). (B) The corresponding PET image in the same patient reveals increased activity of the band heterotopia relative to the adjacent normal cortex (arrows), of unclear significance. (From Chen MYM, Pope TL, Ott DJ. Basic Radiology. 2nd ed. Copyright © The McGraw-Hill Companies, Inc. All rights reserved.)

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  • 5C: Impaired Motor Function and Sensory Integrity Associated with Nonprogressive Disorders of the Central Nervous System—Congenital Origin or Acquired in Infancy or Childhood1



A 5-year-old is referred to physical therapy following decompression surgery for an Arnold–Chiari malformation. Pre-op, the child was complaining of headaches, nausea, vomiting, and had nystagmus and balance difficulties. The child had a history in preschool and kindergarten of poor fine motor and handwriting skills. Upon examination, the therapist notes difficulty walking on a low-balance beam, standing on one leg for more than 2 ...

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