| Ductus venosus | |
|---|---|
 | |
 Theliver and the veins in connection with it, of a human embryo, twenty-four or twenty-five days old, as seen from the ventral surface. | |
| Details | |
| Source | Umbilical vein |
| Drains to | Inferior vena cava |
| Artery | Ductus arteriosus |
| Identifiers | |
| Latin | ductus venosus |
| Anatomical terminology | |
In thefetus, theductus venosus ("DV";Arantius' duct afterJulius Caesar Aranzi[1]) shunts a portion ofumbilical vein blood flow directly to theinferior vena cava.[2] Thus, it allows oxygenated blood from theplacenta to bypass theliver. Compared to the 50% shunting of umbilical blood through theductus venosus found in animal experiments, the degree of shunting in the human fetus under physiological conditions is considerably less, 30% at 20 weeks, which decreases to 18% at 32 weeks, suggesting a higher priority of the fetal liver than previously realized.[3] In conjunction with the other fetal shunts, theforamen ovale andductus arteriosus, it plays a critical role in preferentially shunting oxygenated blood to the fetal brain. It is a part offetal circulation.
The pathway of fetal umbilical venous flow is
umbilical vein left portal veinductus venosusinferior vena cava eventually right atrium.
This anatomic course is important to recall when assessing the success of neonatal umbilical venous catheterization, as failure to cannulate through theductus venosus results in malpositioned hepatic catheterization via the left or right portal veins. Complications of such positioning can include hepatic hematoma or abscess.
Theductus venosus is open at the time of birth, and that is the reason why a catheter inserted into the umbilical vein (umbilical veincatheterization / "UVC") can reach the inferior vena cava; absent a patentDV, such a catheter would continue into the portal vein. Theductus venosus naturally closes during the first week of life in most full-term neonates; however, it may take much longer to close in pre-term neonates. Functional closure occurs within minutes of birth. Structural closure in term babies occurs within 3 to 7 days.
After theductus venosus closes, its remnant is known asligamentum venosum.
If theductus venosus fails to occlude after birth, it remains patent (open), and the individual is said to have a patentductus venosus and thus an intrahepaticportosystemic shunt (PSS).[4] This condition is hereditary in some dog breeds (e.g.Irish Wolfhound). Theductus venosus shows a delayed closure inpreterm infants, with no significant correlation to the closure of theductus arteriosus or the condition of the infant.[5] Possibly, increased levels of dilating prostaglandins leads to a delayed occlusion of the vessel.[5]
