Paraumbilical veins
The paraumbilical veins are small veins that run alongside the umbilicus (navel) and are part of the portal venous system. These veins are clinically significant due to their role in portal hypertension and the formation of caput medusae.
Anatomy[edit]
The paraumbilical veins are located in the falciform ligament of the liver, which is a fold of peritoneum that attaches the liver to the anterior abdominal wall. These veins connect the superior epigastric vein and the inferior epigastric vein with the left branch of the portal vein.
The paraumbilical veins are remnants of the fetal umbilical vein, which carries oxygenated blood from the placenta to the fetus. After birth, the umbilical vein obliterates and becomes the ligamentum teres hepatis, but the paraumbilical veins can remain patent and become significant in certain pathological conditions.
Clinical significance[edit]
In conditions of portal hypertension, such as cirrhosis of the liver, the pressure in the portal venous system increases. This can lead to the reopening of the paraumbilical veins, which then act as collateral channels to divert blood from the high-pressure portal system to the lower-pressure systemic venous system.
The reopening of these veins can lead to the formation of caput medusae, a condition where the veins around the umbilicus become distended and visible under the skin, resembling the head of Medusa from Greek mythology. This is a classic sign of portal hypertension and can be observed in patients with advanced liver disease.
Pathophysiology[edit]
The pathophysiology of paraumbilical vein dilation involves increased resistance to blood flow through the liver, often due to cirrhosis. As the liver becomes fibrotic, blood flow through the portal vein is impeded, leading to increased pressure. The body compensates by opening collateral pathways, including the paraumbilical veins, to bypass the liver.
Surgical considerations[edit]
In some surgical procedures, such as portosystemic shunt surgery, the paraumbilical veins may be utilized to create a bypass for portal blood flow. Understanding the anatomy and function of these veins is crucial for surgeons dealing with portal hypertension and its complications.
