[Prenatal diagnosis of type II Arnold Chiari malformation].

During a 7-year-period 22 foetuses with an Arnold-Chiari deformity were diagnosed. The reason for referring to our centre were severe additional malformations. In 2 cases protrusion of the fetal brainstem is documented by sonography prenatally. Prenatal diagnosis of an ACM has not been documented in the literature. The cytogenetic and microbiological findings including the additional malformations are presented. Pathogenesis, outcome and treatment options are discussed.