Umbilical cord from and contains remnants of the yolk sac and allantois. It forms by the fifth week of development, replacing the yolk sac as the source of nutrients for the embryo. The cord is not directly connected to the mother's circulatory system, but instead joins the placenta, which transfers materials to and from the maternal blood without allowing direct mixing. The length of the umbilical cord is approximately equal to the crown-rump length of the fetus throughout pregnancy. The umbilical cord in a full term neonate is usually about 50 centimeters (20 in) long and about 2 centimeters (0.75 in) in
Souffle (heart sound) the rush of blood through the dilated vessels of the uterus. On auscultation, uterine souffle may often be confused with funic souffle, which is a sharp, whistling sound that is synchronous with the pulse of the foetus. Therefore, the maternal pulse must be palpated simultaneously in order to confirm uterine souffle. Uterine souffle is considered as a probable objective sign of pregnancy. Funic souffle (also known as funicular or fetal souffle), is a blowing sound heard in synch with fetal heart sounds, and may originate from the umbilical cord. It has also been described as a sharp, whistling sound that