Arnold-Chiari malformation

malformed posterior fossa structures resulting from caudad traction and displacement of the rhombencephalon caused by tethering of the spinal cord; may or may not be accompanied by spina bifida and associated anomalies such as meningomyelocele; weak evidence of autosomal recessive inheritance. Syn: Arnold-Chiari deformity, Arnold-Chiari syndrome, cerebellomedullary malformation syndrome.