EVOLUTION OF KNOWLEDGE ON CRANIOVERTEBRAL ANOMALIES AND ARNOLD–CHIARI MALFORMATION: HISTORICAL, MORPHOLOGICAL, AND DIAGNOSTIC PERSPECTIVES

Abstract

The study explores the historical development, classification, and diagnostic evolution of craniovertebral anomalies with a focus on Arnold–Chiari malformation. Over the past three centuries, the understanding of these conditions has progressed from descriptive anatomical observations to detailed radiological and genetic analyses. The work traces the contributions of early anatomists such as R. Columbus, H. Chiari, and J. Arnold, and the refinement of classifications by modern researchers. Special attention is given to the morphogenesis of the craniovertebral junction, the relationship between bone malformations and posterior fossa size, and the pathogenesis of cerebellar tonsil descent. Despite advancements in MRI diagnostics, the etiopathogenesis of Arnold–Chiari malformation remains controversial, with competing theories involving hydrocephalus, traction, and osteoneural disproportion. This review highlights the complex interplay of embryological, anatomical, and radiological factors that continue to shape current diagnostic and clinical approaches.