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Vein: Umbilical vein
Fetal circulation; the umbilical vein is the large, red vessel at the far left.
Human embryo about fifteen days old. Brain and heart represented from right side. Digestive tube and yolk sac in median section. (Umbilical vein labeled at bottom right.)
Latin	vena umbilicalis
Gray's	subject #135 519
Artery	umbilical artery
Dorlands/Elsevier	v_05/12852143

The umbilical vein is a blood vessel present during fetal development that carries oxygenated blood from the placenta to the growing fetus.

Contents 1 Circulation 2 Closure 3 Recanalization 4 Catheterization 5 Additional images 6 References 7 External links 8 See also

Attached to the uterine lining, the placenta is the site of gas exchange between mother and fetus. The singular umbilical vein carries oxygenated blood from the placenta to the fetus, while two umbilical arteries return deoxygenated blood to the placenta. The three vessels coil around one another within the Wharton's jelly of the umbilical cord and enter the abdomen at the umbilicus.

Inside the fetus, the vein courses alongside the falciform ligament and then to the liver's underside. At the transverse fissure, the vein divides into two vessels, one larger than the other. The larger of the two is joined by the portal vein, and together they enter the right lobe of the liver. The smaller vessel, now called the ductus venosus, diverges away from the liver and joins with the inferior vena cava.

Within a week of birth, the infant's umbilical vein is completely obliterated and is replaced by a fibrous cord called the round ligament of the liver (also called the ligamentum teres hepatis, from the Latin meaning the same). It extends from the umbilicus to the transverse fissure, where it joins with the ligamentum venosum to separate the left and right lobes of the liver.

Closure of the umbilical vein usually occurs after the umbilical arteries have closed. This prolongs the communication between the placenta and fetal heart, allowing for a sort of autotransfusion of remaining blood from the placenta to the fetus.

Under extreme pressure, the round ligament may reopen to allow the passage of blood. Such recanalization is common in patients with cirrhosis and portal hypertension. Patients with cirrhosis experience rapid growth of scar tissue in and around the liver, often functionally obstructing nearby vessels. Vessel occlusion increases vascular resistance and therefore leads to hypertension. In portal hypertension, the vessels surrounding the liver are subjected to abnormally high blood pressure—so high, in fact, that the force of the blood pressing against the round ligament is sufficient to recanalize the structure.

A newborn baby has a patent umbilical vein for at least a few months. This umbilical vein may be catheterised for ready intravenous access. It may be used as a site for regular transfusion in cases of erythroblastosis or hemolytic disease.

Model of human embryo 1.3 mm. long.	Scheme of placental circulation.	Diagram of the vascular channels in a human embryo of the second week.	Human embryo with heart and anterior body-wall removed to show the sinus venosus and its tributaries.
Schematic figure of the bursa omentalis, etc. Human embryo of eight weeks.	Liver with the septum transversum. Human embryo 3 mm. long.	Tail end of human embryo twenty-five to twenty-nine days old.

• Gray's s139 - "Peculiarities in the vascular system of the fetus"

• Embryology at Temple Heart98/heart97a/sld020

• Human umbilical vein graft

v • d • e Veins of the torso
Coronary	coronary sinus (great cardiac, left marginal, small cardiac, middle cardiac, posterior of the left ventricle, oblique of the left atrium) • anterior cardiac (right marginal) • pulmonary
Thorax/ SVC	brachiocephalic: inferior thyroid - thymic - internal thoracic (anterior intercostal, superior epigastric) - left superior intercostal - supreme - vertebral - internal jugular - subclavian (axillary: lateral thoracic, thoracoepigastric) - pericardiacophrenic azygos: right superior intercostal - bronchial - intercostal/posterior intercostal 5-11 - accessory hemiazygos/hemiazygos - superior phrenic
Vertebral column	vertebral venous plexuses (external, internal) • spinal (posterior, anterior) • basivertebral • intervertebral
Abdomen/ IVC	to IVC (some to renal vein on left): inferior phrenic - hepatic - suprarenal - renal - gonadal (ovarian ♀/testicular ♂, pampiniform plexus ♂) - lumbar - common iliac to azygos system: ascending lumbar (subcostal)
Pelvis/common iliac	median sacral vein external iliac: inferior epigastric - deep circumflex iliac vein internal iliac - posterior: iliolumbar - superior gluteal - lateral sacral internal iliac - anterior: inferior gluteal - obturator - uterine ♀ (uterine plexus ♀) - vesical (vesical plexus, prostatic plexus ♂, deep of penis ♂/clitoris ♀, posterior scrotal ♂/labial ♀) - vaginal plexus/vein ♀ - middle rectal - internal pudendal (inferior rectal, bulb of penis ♂/vestibule ♀) - rectal plexus
Portal system/ portal vein	splenic: short gastric - left gastroepiploic - pancreatic - inferior mesenteric (superior rectal, left colic) superior mesenteric: right gastroepiploic - pancreaticoduodenal - jejunal - ileal - middle colic - right colic - ileocolic (appendicular) direct (cystic, left gastric/esophageal, right gastric, paraumbilical)
fetal	ductus venosus • umbilical

v • d • e Developmental biology > Human embryogenesis (development of embryo) and development of fetus (some dates are approximate - see Carnegie stages and a timeline)
Week 1	Fertilization - Egg activation - Zygote - Cleavage - Morula - Blastula (Blastomere) - Blastocyst - Inner cell mass
Week 2	Bilaminar disc (Hypoblast, Epiblast)
Week 3 (Trilaminar embryo, germ layers)	Archenteron/Primitive streak (Primitive pit, Primitive knot/Blastopore, Primitive groove) - Gastrula/Gastrulation - Regional specification Ectoderm: Surface ectoderm - Neuroectoderm - Somatopleure - Neurulation - Neural crest Endoderm: Splanchnopleure Mesoderm: Chorda- - Paraxial (Somite/Somitomere/Sclerotome/Myotome/Dermatome) - Intermediate - Lateral plate (Intraembryonic coelom, Splanchnopleure/Somatopleure)
Extraembryonic/uterus	Trophoblast (Cytotrophoblast, Syncytiotrophoblast) Blastocoele - Yolk sack/exocoelomic cavity - Heuser's membrane - Extraembryonic coelom - Vitelline duct Umbilical cord (Umbilical artery, Umbilical vein, Wharton's jelly) - Allantois Placenta - Decidua (Decidual cells) - Chorionic villi/Intervillous space - Gestational sac (Amnion/Amniotic sac/Amniotic cavity, Chorion)
Histogenesis	Programmed cell death - Stem cells - Germ line development
Organogenesis	Limb development: Limb bud - Apical ectodermal ridge/AER - Eye development - Cutaneous structure development - Heart development - Development of the urinary and reproductive organs

v • d • e Prenatal development/Mammalian development of circulatory system
Vascular	Blood island arteries: Dorsal aorta - Aortic arches - Vitelline arteries - Ductus arteriosus - Umbilical artery veins: Cardinal veins - Ducts of Cuvier - Vitelline veins - Ductus venosus - Umbilical vein
Heart development	Primitive heart tube: Truncus arteriosus - Bulbus cordis - Primitive ventricle - Primitive atrium - Sinus venosus Septum primum (Ostium primum, Ostium secundum) - Septum secundum (Foramen ovale) - other septa (Endocardial cushions/Septum intermedium, Aorticopulmonary septum) - Atrial canal