<prompt> Banana sign on USG is seen in :Arnold Chiari malformationHoloprosencephalyDandy walker malformationAnencephaly  <response>: Compression or flattening of the posterior cerebellar surface making a crescentic appearance banana sign is seen in open spina bifida and Arnols Chairis malformation. Reference: Duttas Textbook of Obstetrics 7th edition page no 647 