Human Fetus at 21 Weeks in the Womb (Asian Skin)

Description

A fetus at approximately 21 weeks of gestation lies in a flexed attitude within the amniotic cavity, presented in a left lateral aspect. The large, rounded cranial vault dominates the profile, with the auricle of the external ear modelled in detail and the neck flexed so the chin approaches the chest. Both upper limbs are drawn across the anterior trunk with the fingers separated and distinct, while the lower limbs are folded tightly at hip and knee against the abdomen, and the smoothly curved back and buttocks form the outer contour of the body. The umbilical cord passes from the ventral abdominal wall around the shoulder and upward to the textured placental surface at the upper right, its coiled course exposing the two umbilical arteries and the single umbilical vein against the vascularised uterine wall behind. The second trimester at around 21 weeks corresponds closely with the timing of the routine mid-pregnancy anomaly scan, when biometry such as biparietal diameter, head and abdominal circumference and femur length is measured and fetal position, limb development and cord insertion are systematically assessed. Depicting the three-vessel cord and its placental attachment supports discussion of single umbilical artery, velamentous or marginal insertion, and nuchal cord loops. The tightly flexed posture also illustrates the physiological fetal attitude and the normal range of movement observed sonographically at this stage. The rendering suits obstetric and midwifery teaching on second-trimester development, antenatal clinic and patient education material explaining what parents see at the twenty-week scan, and embryology or reproductive biology atlases requiring a consistent week-by-week series. Publishers, ultrasound training providers and pregnancy application developers can pair it with the neighbouring week 20 and week 22 images for a continuous developmental sequence. Anatomical accuracy verified by SciePro's Medical Advisory Board.