Uterus
Schematic diagram comparing normal placenta (left) and circumvallate placenta (right). The membranes insert at the edge of the normal placenta, whereas they insert on the anterior surface of the circumvallate placenta, central to the placental edge. As a result, the circumvallate placenta has a raised rolled layer of thickened membranes and placental tissue resulting in a clublike appearance of the placental edge. Cireumvallate placenta. A, Longitudinal image of the uterus during late second trimester shows a posterior placenta (P) with raised edges in a clublike configuration (arrows) due to circumvallate placenta. Oblique image of the same placenta (P) as in image A depicts the raised edge of the placenta as a linear band of tissue (arroes) that resembles a uterine synechia.
