Current understanding of cerebellar ectopia is primarily based on the detailed study and classification of this rare rhombencephalon deformity by Hans Chiari, MD, more than a century ago. Recent advances in neuroradiology, especially since the introduction of magnetic resonance imaging, have enabled the incidental diagnosis of cerebellar ectopia. This radiographic finding, increasingly observed in asymptomatic adults, presents a different clinical scenario than that characterized by Chiari, making application of Chiari's original classification scheme often difficult. This article highlights Chiari's observations of cerebellar ectopia and those of other seminal figures, relating their findings to modern recognition of this entity.
Arnett B. Arnold-Chiari Malformation. Arch Neurol. 2003;60(6):898-900. doi:10.1001/archneur.60.6.898