Human Fetus at 17 Weeks in the Womb (Caucasian Skin)

Description

At approximately 17 weeks of gestation the fetus lies curled in the flexed fetal position inside the translucent amniotic sac, surrounded by amniotic fluid and enclosed by the uterine wall. The head is seen in profile, dominated by the large cranial vault relative to the face, with closed eyelids, a formed nose and lips, and a well modelled external ear on the side of the head. The upper limb is flexed with the fingers of the hand loosely curled near the chin, while the lower limbs are drawn up with the knees bent and the sole of the foot turned toward the viewer. The umbilical cord emerges from the abdominal wall and spirals toward the discoid placenta seen at the right, its vessels branching across the chorionic plate. The second trimester at this stage is defined by rapid somatic growth, ossification of the skeleton and the beginnings of coordinated limb movement, and it is the window in which detailed anomaly ultrasound is planned. The relationship of fetal lie, cord insertion and placental position illustrated here underpins routine sonographic assessment of placental location, cord insertion site and amniotic fluid volume, and it is the anatomy referenced during amniocentesis, where needle path must avoid the fetus and cord. Fetal biometry such as biparietal diameter and femur length is taken from precisely these structures. The rendering suits obstetric and midwifery teaching, prenatal classes and antenatal clinic waiting-room material, where patients benefit from seeing the scale and posture of the fetus at a stage described in their scan report. Embryology and developmental anatomy courses can place it in a week-by-week gestational series, and publishers, health websites and pregnancy applications can use it as a figure for second-trimester development. Anatomical accuracy verified by SciePro's Medical Advisory Board.