Umbilical artery


The umbilical artery is a paired artery that is found in the abdominal and pelvic regions. In the fetus, it extends into the umbilical cord.

Structure

Development

The umbilical arteries supply deoxygenated blood from the fetus to the placenta. Although this blood is typically referred to as deoxygenated, it is important to note that this blood is fetal systemic arterial blood and will have the same amount of oxygen and nutrients as blood distributed to the other fetal tissues. There are usually two umbilical arteries present together with one umbilical vein in 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 that supply the hind limbs with blood and nutrients in the fetus.
The umbilical arteries are one of two arteries in the human body, that carry deoxygenated blood, the other being the pulmonary arteries.
The pressure inside the umbilical artery is approximately 50 mmHg.

After development

The umbilical artery regresses after birth. A portion obliterates to become the medial umbilical ligament. A portion remains open as a branch of the anterior division of the internal iliac artery. The umbilical artery is found in the pelvis, and gives rise to the superior vesical arteries. In males, it may also give rise to the artery to the ductus deferens which can be supplied by the inferior vesical artery in some individuals.

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