Arnold-Chiari malformation

pathology

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Last updated

June 18, 2026

Quick Summary

The Arnold-Chiari malformation is a condition where brain tissue, specifically the cerebellar tonsils, extends into the foramen magnum, the opening at the base of the skull that connects to the spinal cord. This can lead to various symptoms, depending on the severity and cause.1

In some cases, this malformation can cause cerebellar dysfunction, hydrocephalus (an accumulation of cerebrospinal fluid in the brain), or widening of the spinal cord's central canal. Symptoms can range from headaches and neck pain to more severe issues like breathing or eating difficulties, particularly in infants. The foramen magnum is crucial for connecting the brain and spinal cord and allows passage for blood vessels and nerves. When brain tissue protrudes through it, it can compress vital structures.21

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nervous system disease
Cephalic disorders
In the Arnold-Chiari malformation, cerebellar or medullary tissue projects downward into the upper cervical spinal canal, causing cerebellar dysfunction, hydrocephalus, or widening of the central canal of the spinal cord with damage to surrounding fibre tracts. Fusion of the upper cervical vertebrae occurs in Klippel-Feil syndrome.
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In the Arnold-Chiari malformation, cerebellar or medullary tissue projects downward into the upper cervical spinal canal, causing cerebellar dysfunction, hydrocephalus, or widening of the central canal of the spinal cord with damage to surrounding fibre tracts. Fusion of the upper cervical vertebrae occurs in Klippel-Feil syndrome.
Read More