Chiari II Malformation: Pathophysiology, Imaging Features, Diagnosis, and Treatment – A Comprehensive Review
Introduction Chiari II malformation, also referred to as Arnold–Chiari malformation, represents a complex congenital hindbrain anomaly with significant clinical implications. It is most often associated with myelomeningocele and manifests with a combination of structural, neurological, and developmental abnormalities. Understanding Chiari II malformation requires an in-depth examination of its pathophysiology, epidemiology, clinical presentation, imaging features, differential diagnosis, treatment strategies, and prognosis. This article aims to provide a comprehensive, expert-level review of Chiari II malformation, supported by the latest evidence-based research, while optimizing for academic and clinical relevance. Pathophysiology Chiari II malformation is characterized by the downward displacement of the cerebellar vermis, tonsils, medulla, and fourth ventricle through the foramen magnum. The condition is thought to arise due to abnormal development of the posterior fossa. A sm...