It consists of a downward herniation of the brain-cerebellar vermis and the medulla through the foramen magnum, sometimes causing hydrocephalus as a result of obstruction of cerebrospinal fluid (CSF) outflow .
It can cause vertigo(dizziness), headaches, fatigue, muscle weakness in the head and face, difficulty swallowing, nausea, impaired coordination, and paralysis.
The incidence of Chiari 1 malformation, defined as tonsilar herniations of 3 to 5 mm or greater.
Once symptomatic onset occurs, treatment is decompression surgery by neurosurgeons.
post op picture
(An Austrian pathologist, Hans Chiari, first described these hindbrain malformations in the 1890s. A colleague of Professor Chiari, Dr. Julius Arnold, later contributed to the definition of the condition, and students of Dr. Arnold suggested the term “Arnold-Chiari malformation” to henceforth refer to the condition.)
