Umbilical artery the umbilical cord. The umbilical arteries surround the urinary bladder and then carry all the deoxygenated blood out of the fetus through the umbilical cord. Inside the placenta, the umbilical arteries connect with each other at a distance of approximately 5 mm from the cord insertion in what is called the "Hyrtl anastomosis". Subsequently, they branch into chorionic arteries or "intraplacental fetal arteries". The umbilical arteries are actually the latter of the internal iliac arteries (anterior division of) that supply the hind limbs with blood and nutrients in the fetus. The umbilical arteries are one of two arteries in the
Umbilical ring vessels. Cranially it lies ventral to the umbilical vein and on each side extends into the tissue of the lateral pillars of the cord bounding the coelom. When the myotomic downgrowths reach the ventral aspect, their anterior portions (i.e. the sheaths of the recti muscles) become continuous with the tissue of the umbilical ring. Umbilical ring The umbilical ring is a dense fibrous ring surrounding the umbilicus at birth. At about the sixth week of embryological development, the midgut herniates through the umbilical ring; six weeks later it returns to the abdominal cavity and rotates around the superior mesenteric artery.