Fetus at Week 18

Description

Fetus at 18 weeks’ gestation occupies the frame with the placenta attached by a single umbilical cord, allowing the fetal body, cord insertion, and placental disk to be appreciated in one fixed composition. The cephalic pole remains proportionally large relative to the trunk, while the upper and lower limbs extend laterally from the shoulder and hip regions with distinct forearm, leg, and digital segmentation. Along the ventral body wall, the umbilical cord courses from the fetal umbilicus toward the placental chorionic plate, where it inserts and fans into placental vasculature within the disk. Placental maternal and fetal surfaces are differentiated by contour and texture, and the cord appears as a smooth tubular structure consistent with Wharton’s jelly surrounding one umbilical vein and paired umbilical arteries. Week 18 sits squarely in the second trimester, when obstetric assessment shifts from early viability concerns to anatomic survey and placental localization. Placenta previa, abnormal placental implantation, or a velamentous cord insertion are all conditions where understanding placental topography and the cord’s relationship to the placental disk matters before counseling, follow-up ultrasound, or planning delivery. Depth cues and clean separation from the white background keep attention on fetal proportions and the cord-placenta unit rather than distracting maternal anatomy. A compact but realistic overview. Use this illustration in embryology and human development teaching to anchor second-trimester milestones, or in obstetrics and prenatal care materials that explain placental function, fetoplacental circulation, and why cord insertion is documented at the mid-gestation anatomy scan. It also fits patient-facing brochures and publisher figures where an isolated fetus with placenta supports discussion of gestational age, screening, and routine prenatal ultrasound findings. Anatomical accuracy verified by SciePro's Medical Advisory Board.