Final answer:
Esophageal varices form at the anastomosis of the esophageal veins and the azygos/hemiazygos system, which are stressed due to increased pressure in the hepatic portal system often caused by liver disease like cirrhosis.
Step-by-step explanation:
Esophageal varices, commonly associated with liver disease, particularly cirrhosis, are enlarged veins that form in the esophagus due to increased pressure in the portal venous system. They result from the anastomosis of the esophageal veins, which drain the inferior portions of the esophagus and lead to the azygos vein, and the hemiazygos veins, which are smaller veins complementary to the azygos vein that also drain the esophageal veins from the esophagus and the left intercostal veins, leading to the brachiocephalic vein via the superior intercostal vein.
The hepatic portal system, including the hepatic portal vein, plays a significant role in the formation of esophageal varices. Blood from digestive organs is carried to the liver for processing through this system. If there is a blockage or high resistance to blood flow within the liver, as in liver cirrhosis, it can cause a buildup of pressure in the portal system, leading to the development of esophageal varices.