Knowra Chiari malformation Chiari malformation Chiari malformation is a structural condition in which brain tissue extends abnormally through the opening at the base of the skull into the spinal canal. It can obstruct cerebrospinal fluid flow and cause neurological symptoms.
Cerebrospinal fluid : Clear fluid that circulates through the brain’s ventricles and around the brain and spinal cord. Crowding at the skull base can disrupt its circulation between the brain and spinal canal.
Cerebellum : The brain region that coordinates movement, balance, and aspects of motor learning. The cerebellar tonsils are commonly the tissue that descends in Chiari I.
Magnetic resonance imaging : An imaging technique that uses magnetic fields and radio waves to produce detailed images of internal structures. MRI shows tissue position, cerebrospinal fluid spaces, and associated spinal cord cavities.
Cerebellar tonsillar ectopia : A descriptive finding in which the cerebellar tonsils lie lower than usual, without necessarily meeting criteria for Chiari I. Low-lying tonsils alone do not establish a symptomatic Chiari malformation.
Foramen magnum : The large opening in the base of the skull through which the brainstem continues as the spinal cord. Chiari malformation involves tissue extending through this opening.
Cerebellar tonsils : Rounded structures on the lower surface of the cerebellum. Their position relative to the foramen magnum is central to diagnosing Chiari I.
Neurological examination : A clinical assessment of functions such as strength, sensation, reflexes, coordination, and cranial nerves. Findings help determine whether an imaging abnormality is causing neurological impairment.
Idiopathic intracranial hypertension : Raised pressure inside the skull without an identifiable mass or other underlying cause. It can produce low-lying cerebellar tonsils that resemble Chiari I on imaging.
Syringomyelia : A fluid-filled cavity, or syrinx, within the spinal cord. Impaired fluid flow associated with Chiari malformation can contribute to syrinx formation.
Posterior cranial fossa : The compartment at the back of the skull containing the cerebellum and brainstem. Its size and shape can affect crowding near the skull’s base.
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