Human Fetus at 16 Weeks in the Womb (Caucasian Skin)

Description

A fetus of approximately 16 weeks gestation lies in a flexed attitude within the translucent amniotic sac, seen from the left side. The cranial vault is large in proportion to the trunk, the facial profile shows a formed nose, closed eyelids and modelled lips, and the external ear (auricle) is fully sculpted on the side of the head. The upper limb is flexed at the elbow with the fingers brought to the mouth, while the lower limbs are drawn up with distinct knees, ankles and separated toes. Amniotic fluid fills the sac, the abdominal wall shows the umbilical cord insertion, and the vascularised uterine wall forms the surrounding chamber. The mid-second trimester is the period in which fetal anatomy becomes reliably assessable by ultrasound, and images of this stage support explanation of biometry such as biparietal diameter, head circumference, abdominal circumference and femur length. Limb posture, hand-to-mouth movement and swallowing of amniotic fluid are established by week 16, which underpins discussion of fetal neurological maturation and of amniotic fluid dynamics. The intact sac and cord insertion also give context for counselling on amniocentesis timing, anomaly screening and normal placental and membrane relationships. Suitable for obstetric and midwifery teaching resources, embryology and prenatal development atlases, antenatal clinic and patient education material explaining what a pregnancy looks like at four months, and editorial or publication figures on fetal growth. As part of a week-by-week series it allows direct visual comparison with earlier embryonic stages for students, sonographers and expectant parents. Anatomical accuracy verified by SciePro's Medical Advisory Board.