Human Fetus at 20 Weeks in the Womb, Lateral View (Black Skin)

Description

At approximately 20 weeks of gestation the fetus lies in a flexed attitude within the translucent amniotic sac, shown here in lateral profile with the head to the left and the spine curved along the lower margin of the cavity. The cranium is large in proportion to the trunk, the external ear is modelled on the side of the head, and the eyelids remain fused. Both upper limbs are drawn toward the face with the fingers separated and distinct, while the lower limbs are folded at the hips and knees so that the feet approach the buttocks. The umbilical cord emerges from the abdominal wall as a spiralled structure in which the paired umbilical arteries and single umbilical vein can be traced toward the fetal surface of the placenta, whose chorionic vessels radiate across the disc where it is apposed to the vascular uterine wall. Amniotic fluid surrounds the fetus on all sides. Twenty weeks marks the conventional midpoint of pregnancy and the usual timing of the detailed second-trimester anomaly scan, when biometry such as biparietal diameter, head and abdominal circumference and femur length is recorded and compared with reference charts. The relationships shown here underpin obstetric ultrasound reporting: placental site and its distance from the internal cervical os, cord insertion, number of cord vessels, and amniotic fluid volume. Fetal posture, limb movement and the developing digits are also assessed at this stage, and the same anatomy frames counselling about growth restriction, placenta praevia and cord abnormalities. The rendering suits obstetric and midwifery teaching, embryology and developmental anatomy lectures, antenatal class handouts and clinic wall charts explaining what a mid-pregnancy scan shows. It also serves publishers producing pregnancy week-by-week series, apps and journal figures, and healthcare communication teams needing a consistent set of images across successive gestational weeks. Anatomical accuracy verified by SciePro's Medical Advisory Board.