tonsillar herniation

Also called tonsillar herniation.

For further evaluation of tonsillar herniation, CINE flow studies are used.

These include hydrocephalus, cerebellar tonsillar herniation (Chiari I), seizures and syringomyelia.

Neuroradiological investigation is used to first discount any intracranial condition that could be responsible for intracranial pressure and tonsillar herniation.

Some clinicians have reported that some patients appear to experience symptoms consistent with a Chiari malformation without radiographic evidence of tonsillar herniation.

Elongation of the cerebellar tonsils can, due to pressure, lead to this portion of the cerebellum to slip or be pushed through the foramen magnum of the skull resulting is tonsillar herniation.

Tonsillar herniation of the cerebellum is also known as a Chiari Malformation (CM), or previously an Arnold Chiari Malformation (ACM).

There are many suspected causes of tonsillar herniation including: decreased or malformed posterior fossa (the lower, back part of the skull) not providing enough room for the cerebellum; hydrocephalus or abnormal CSF volume pushing the tonsils out.

A consequence of this disproportionate brain growth appears to be a significantly increased risk of cerebellar tonsillar herniation (descent of the cerebellar tonsils through the foramen magnum of the skull, resembling a Chiari I malformation neuroradiologically) and ventriculomegaly/hydrocephalus.

In tonsillar herniation, also called downward cerebellar herniation, or "coning", the cerebellar tonsils move downward through the foramen magnum possibly causing compression of the lower brainstem and upper cervical spinal cord as they pass through the foramen magnum.