1883年Cleland最先描述了“脑干和第四脑室下移进入颈椎管”的疾病。8年后,Chiari描述了下列几种病例:(1)小脑扁桃体拉长,与部分小脑下叶向尾侧移入颈椎管,即ChiariⅠ畸形;(2)小脑扁桃体与部分小脑移入颈椎管,第四脑室拉长,也移向尾侧,50%的病例延髓扭曲,常见脑积水,多见于婴幼 In 1883 Cleland first described the “brain stem and the fourth ventricle down into the cervical canal” disease. Eight years later, Chiari described the following cases: (1) cerebellar tonsils elongated, and part of the lower cerebella shifted caudal to the cervical spinal canal, Chiari Ⅰ deformity; (2) the cerebellar tonsillar and some cerebella into the cervical canal, the fourth Ventricular elongation, also moved to the caudal, medullary twisting of 50% of cases, common hydrocephalus, more common in infants and young children