cerebellar tonsillar herniation
Downward displacement of the cerebellar tonsils through the foramen magnum, potentially compressing the brainstem.
Full Definition
Cerebellar tonsillar herniation occurs when increased intracranial pressure forces the cerebellar tonsils to descend through the foramen magnum, the opening at the base of the skull. This herniation can compress vital brainstem structures, including the medulla oblongata, which controls respiratory and cardiac functions. The condition may be acute, as in cases of severe brain swelling, or chronic, as seen in Chiari malformations. Symptoms can include neck pain, difficulty swallowing, respiratory compromise, and potentially fatal brainstem compression requiring emergency decompression surgery.
Usage
Usage note: Often associated with Chiari malformations but can occur acutely due to increased intracranial pressure from various causes.
In Context
- "Post-operative imaging showed evidence of cerebellar tonsillar herniation requiring immediate decompressive measures." — Neurosurgical consultation note