RT Book, Section A1 Matias, Alexandra A1 Jeanty, Philippe A1 Toy, Eugene C. A2 Fleischer, Arthur C. A2 Toy, Eugene C. A2 Lee, Wesley A2 Manning, Frank A. A2 Romero, Roberto J. SR Print(0) ID 1106706170 T1 SONOGRAPHY IN MULTIPLE GESTATION T2 Sonography in Obstetrics and Gynecology: Principles & Practice, 7e YR 2015 FD 2015 PB McGraw-Hill Education PP New York, NY SN 9780071547727 LK obgyn.mhmedical.com/content.aspx?aid=1106706170 RD 2024/03/28 AB DefinitionsMonozygotic twins: a pregnancy of 2 fetuses derived from the same zygote that divided between the day of fertilization and the 14th day. They can have phenotypic and genotypic differences and can have either a dichorionic or a monochorionic placentation.Dizygotic twins: a pregnancy of 2 fetuses derived from 2 different zygotes, resulting from the fertilization of 2 oocytes from the same cycle. They always have a dichorionic placentation.Chorionicity: type of placentation in cases of multiple pregnancy defined by the number of chorions.Lambda sign: sonographic sign resulting from the juxtaposition of 2 layers of amnion and 2 layers of chorion in a dichorionic twin pregnancy.