Arnold-Chiari malformation is a congenital deformity of rear brain, i.e. anomaly of the lower part of cerebral stem and cerebellum involving their caudal displacement through foramen magnum into the spinal canal. Early diagnosis and adequate treatment may be decisive for further psychomotor development of an affected individual.
Here we present a case of a state-of-the-art prenatal diagnosis of Arnold-Chiari syndrome using 3D extended imaging, 3D/4D ultrasound and fetal MRI-like imaging, together with a literature review of this anomaly rarely diagnosed in prenatal period.