The umbilical artery is a paired

artery An artery () is a blood vessel in humans and most other animals that takes oxygenated blood away from the heart in the systemic circulation to one or more parts of the body. Exceptions that carry deoxygenated blood are the pulmonary arteries in ...

(with one for each half of the body) that is found in the abdominal and

pelvic The pelvis (: pelves or pelvises) is the lower part of an anatomical trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis or pelvic skeleton). ...

regions. In the

fetus A fetus or foetus (; : fetuses, foetuses, rarely feti or foeti) is the unborn offspring of a viviparous animal that develops from an embryo. Following the embryonic development, embryonic stage, the fetal stage of development takes place. Pren ...

, it extends into the

umbilical cord In Placentalia, placental mammals, the umbilical cord (also called the navel string, birth cord or ''funiculus umbilicalis'') is a conduit between the developing embryo or fetus and the placenta. During prenatal development, the umbilical cord i ...

Structure

Development

The umbilical arteries supply systemic arterial blood from the fetus to the

placenta The placenta (: placentas or placentae) is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation. It plays critical roles in facilitating nutrient, gas, and waste exchange between ...

. 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

. The umbilical arteries surround the

urinary bladder The bladder () is a hollow organ in humans and other vertebrates that stores urine from the Kidney (vertebrates), kidneys. In placental mammals, urine enters the bladder via the ureters and exits via the urethra during urination. In humans, the ...

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 A pulmonary artery is an artery in the pulmonary circulation that carries deoxygenated blood from the right side of the heart to the lungs. The largest pulmonary artery is the ''main pulmonary artery'' or ''pulmonary trunk'' from the heart, and ...

. The

pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and eve ...

inside the umbilical artery is approximately 50

mmHg A millimetre of mercury is a manometric unit of pressure, formerly defined as the extra pressure generated by a column of mercury one millimetre high. Currently, it is defined as exactly , or approximately 1 torr = atmosphere = &nb ...

. 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 In human anatomy, the median umbilical ligament is an unpaired midline ligamentous structure upon the lower inner surface of the anterior abdominal wall. It is covered by the median umbilical fold. The median umbilical ligament represents the re ...

, a different structure that represents the remnant of the embryonic

urachus The urachus forms from the distal end of the allantois in the embryo, and develops into a closed cord between the base of the bladder, and the navel. It drains the bladder of the fetus that joins and runs within the umbilical cord. The fibrous r ...

). A portion remains open as a branch of the anterior division of the internal iliac artery. The umbilical artery is found in the

pelvis The pelvis (: pelves or pelvises) is the lower part of an Anatomy, anatomical Trunk (anatomy), trunk, between the human abdomen, abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also c ...

, 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 The inferior vesical artery (or inferior vesical artery) is an artery of the pelvis which arises from the internal iliac artery and supplies parts of the urinary bladder as well as other structures of the urinary system and structures of the male ...

in some individuals.

Clinical significance

catheter In medicine, a catheter ( ) is a thin tubing (material), tube made from medical grade materials serving a broad range of functions. Catheters are medical devices that can be inserted in the body to treat diseases or perform a surgical procedure. ...

may be inserted into one of the umbilical arteries of critically ill babies for drawing blood for testing. 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 infusions.

Additional images

File:Gray31.png, Model of human embryo, 1.3 mm. long. File:Gray1111.png, Transverse section of human embryo, eight and a half to nine weeks old. File:Gray1115.png, Tail end of human embryo, twenty-five to twenty-nine days old. File:Inguinal fossae.PNG, Inguinal fossae File:Slide4khi.JPG, Umbilical artery. Deep dissection. Anterior view. File:Slide4BLA.JPG, Umbilical artery. Deep dissection. Serial cross-section.

References

External links

* - "The Female Pelvis: Branches of Internal Iliac Artery" {{DEFAULTSORT:Umbilical Artery Arteries of the abdomen Embryology of cardiovascular system