TY - CHAP M1 - Book, Section TI - PLACENTA, CORD, AND MEMBRANES A1 - Mastrobattista, Joan M. A1 - Toy, Eugene C. A2 - Fleischer, Arthur C. A2 - Toy, Eugene C. A2 - Lee, Wesley A2 - Manning, Frank A. A2 - Romero, Roberto J. Y1 - 2015 N1 - T2 - Sonography in Obstetrics and Gynecology: Principles & Practice, 7e AB - DefinitionsBasal plate: maternal surface of placenta.Chorioangioma: benign tumors arising from the fetal surface of the placenta.Chorionic plate: fetal surface of placenta.Complete placenta previa: occurs when the placenta completely covers the internal os.Extrachorial placenta (circummarginate and circumvallate): attachment of placental membranes to the fetal surface of the placenta rather than the villous placental margin.Low-lying placenta/low implantation: occurs when the inferior placental edge is within 2 cm of the internal cervical os.Marginal placenta previa: occurs when the placenta extends over the cervix and abuts the internal cervical os.Partial placenta previa: occurs when the placenta partially covers the internal os.Placental abruption: separation of a normally implanted placenta.Succenturiate placenta: the presence of one or more accessory lobes separate from the main placental body.Trophotrophism: a dynamic process of placental remodeling where areas with poor vascularity atrophy and areas of good perfusion grow.Uterine synechia (amniotic sheets): broad-based tissue that extends into the amniotic cavity but is external to the amnion and chorion.Vasa previa: occurs when fetal vessels that run in the fetal membranes cross the internal cervical os. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - obgyn.mhmedical.com/content.aspx?aid=1106704908 ER -