초록
The concept of Chiari malformations emerged toward the end of $19^{th}$ century from Chiari's initial descriptions of "alterations in the cerebellum resulting from cerebral hydrocephalus." In 1891, Hans Chiari(1851-1916) suggested cerebellar ectopia in which he classified Type I as "elongation of the tonsils and medial parts of the inferior lobes of the cerebellum into cone-shaped projections, which accompany the medulla oblongata into the spinal canal. The incidence of Chiari malformation has been found to be between 0.56% and 0.77% on MR imaging studies, as well as 0.62% in brain dissection studies. the definition of the adult Chiari malformation has varied with the evolution of neurodiagnositic capabilities and knowledge of physiopathology. This disorder can be associated with significant symptomatology, risk of secondary injury due to trauma, and the risk of progression and damage of the spinal cord due to associated Syringomyelia. Syringomyelia is found in 50 to 70% of Chiari I malformation. It is the clinical judgment of the physicians evaluating this disorder that is of the importance to avoid the therapeutic extremes of pursuing unnecessary surgery or withholding necessary treatment from patients.