Human Placenta, Anatomy

Description

Placenta anatomy is centered on the fetal surface, where the umbilical cord inserts into the chorionic plate and branches into chorionic vessels that course radially beneath the amnion. From this superior fetal aspect, the smooth chorionic plate contrasts with the lobulated maternal surface, where cotyledons form polygonal units separated by septa of decidua basalis. Along the peripheral margin, the transition from chorionic plate to the placental edge clarifies how fetal membranes relate to the placental disc. Orientation reads clearly. Clinical interpretation often begins with this same gross layout: cord insertion and surface vascular pattern raise immediate flags for velamentous insertion or vasa previa risk, while an irregular, disrupted cotyledonary pattern can suggest retained placental tissue after delivery. The separation between fetal (chorionic) and maternal (basal) plates also frames discussions of placenta accreta spectrum, where abnormal trophoblastic invasion breaches the decidua and anchors too deeply into myometrium, altering the expected cleavage plane at delivery. Emphasis on cotyledons supports teaching how maternal spiral arteries supply the intervillous space and why uteroplacental insufficiency can manifest as smaller, infarcted lobules on gross exam. Use this illustration in obstetrics and gynecology lectures covering placental development, third-stage labor, and postpartum placental examination, or in pathology and anatomy courses teaching chorionic plate versus basal plate organization. It also suits medical publishing on placental variants, cord insertion anomalies, and correlations with prenatal ultrasound findings that map to these macroscopic landmarks. Anatomical accuracy verified by SciePro's Medical Advisory Board.