In the course of the
round ligament of liver, small veins (paraumbilical) are found which establish an
anastomosis
An anastomosis (, plural anastomoses) is a connection or opening between two things (especially cavities or passages) that are normally diverging or branching, such as between blood vessels, leaf#Veins, leaf veins, or streams. Such a connection m ...
between the veins of the
anterior abdominal wall and the
hepatic portal,
hypogastric, and
iliac veins.
The best marked of these small veins is one which commences at the
umbilicus and runs backward and upward in, or on the surface of, the round ligament (ligamentum teres) between the layers of the
falciform ligament to end in the left portal vein.
Pathophysiology
In patients with
portal hypertension
Portal hypertension is abnormally increased portal venous pressure – blood pressure in the portal vein and its branches, that drain from most of the intestine to the liver. Portal hypertension is defined as a hepatic venous pressure gradient gr ...
, the paraumbilical veins may become enlarged in order to reduce hepatic portal vein pressure by shunting blood to the
superficial epigastric vein. The superficial epigastric vein drains to the femoral vein which ultimately drains into the inferior vena cava directly through the external iliac and common iliac vein, thereby bypassing the liver. Dilation of this particular
portacaval anastomosis
A portocaval anastomosis or porto-systemic anastomosis is a specific type of anastomosis that occurs between the veins of the portal circulation and those of the systemic circulation. When there is a blockage of the portal system, portocaval anast ...
results in what is referred to as
caput medusae.
External links
* - "Venous Drainage of the Anterior Abdominal Wall"
Veins of the torso
{{circulatory-stub