Significance of chronic tonsillar herniation in sudden death.

The Chiari I malformation is a congenital abnormality of the cerebellum strongly associated with syringomyelia and also associated with bony abnormalities of the base of the skull and the cervical spine. This review examines the case of a 25 year old man who collapsed and died following a blow to the face and was found at post mortem to have a Chiari I malformation and syringomyelia but no gross or microscopic evidence of fresh brain or spinal cord injury. The occurrence of sudden and unexpected deaths in this condition is discussed especially in the context of apparently minor coincident trauma.