The Nomenclature of Chiari Malformations

The current nomenclature of Chiari malformations includes the standard designations, Chiari 1-4, which were described by Hans Chiari in the late nineteenth century, and more recent additions, Chiari 0, 0.5, and 1.5, which emerged when the standard nomenclature failed to include important anatomical variations. The authors describe these entities and propose that to best optimize clinical care and research, it would be wise to place less focus on the eponyms and more effort on developing a descriptive or pathophysiological nomenclature.