The umbilical artery is a paired artery (with one for each half of the body) that is found in the abdominal and pelvic regions. In the fetus, it extends into the umbilical cord.
Structure
Development
The umbilical arteries supply systemic arterial blood from the fetus to the
placenta. Although this blood is sometimes referred to as deoxygenated blood it is not, and has the same oxygen saturation 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 anterior division of the internal iliac arteries, and retain part of this function after birth.
The umbilical arteries are one of two arteries in the human body that carry deoxygenated blood, the other being the pulmonary arteries.
The Blood pressure inside the umbilical artery is approximately 50 mmHg.[ Fetal and maternal blood circulation systems From Online course in embryology for medicine students. Universities of Fribourg, Lausanne and Bern (Switzerland). Retrieved on 6 April 2009] Resistance to blood flow decreases during development as the artery grows wider.
After development
The umbilical artery regresses after birth. A portion obliterates to become the medial umbilical ligament (not to be confused with the median umbilical ligament, a different structure that represents the remnant of the embryonic
urachus). 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, which in males usually supplies the artery to the ductus deferens. Alternately, the latter artery can be supplied by the inferior vesical artery in some individuals.
Clinical significance
A
catheter may be inserted into one of the umbilical arteries of critically ill babies for
Venipuncture for
Blood test.
This is a common procedure in neonatal intensive care, and can often be performed until 2 weeks after birth (when the arteries start to decay too much).
The umbilical arteries are typically not suitable for
Infusion therapy.
==Additional images==
See also
External links
-
- "The Female Pelvis: Branches of Internal Iliac Artery"
