Human Fetus at 20 Weeks in the Womb (Asian Skin)

Description

The fetus lies in a flexed, head-down attitude within the amniotic cavity, the vertebral contour curving along the back while the knees are drawn up and one hand rests near the mouth. Facial features are formed and the eyelids remain fused, the external ear (auricle) is well modelled against the side of the head, and the digits of the hands and the toes of both feet are fully separated. The umbilical cord, its two arteries and single vein visible as a helical twist, passes from the abdominal insertion across the fetal head toward a discoid placenta applied to the uterine wall. Skin is thin and translucent over the subcutaneous tissue, and vascular markings of the myometrium and the surrounding uterine cavity are visible behind the fetus. At 20 weeks the pregnancy is at the midpoint of gestation and corresponds to the timing of the routine mid-trimester anomaly scan, when biometry such as biparietal diameter, head and abdominal circumference and femur length is recorded, cardiac outflow tracts and the spine are surveyed, and placental site and cord insertion are documented. The relationship shown between cord, fetus and placenta underlies assessments of cord coiling, nuchal cord and placental position, while the flexed posture and active limb movement of this stage are what a mother typically first perceives as quickening. Fetal lie and presentation at this gestation remain variable and are not yet clinically fixed. The rendering supports obstetric and midwifery teaching, antenatal class material and patient-facing week-by-week pregnancy resources, and sits alongside the neighbouring weeks of this series for comparative growth sequences. It is equally suited to embryology and developmental anatomy atlases, ultrasound training aids that pair a schematic scan plane with a realistic model, and editorial or publisher figures on second-trimester development. Anatomical accuracy verified by SciePro's Medical Advisory Board.