In portal hypertension lower end of the oesophagus may show dilatation of veins. Which of the following veins drains into the portal vein from the lower end of the oesophagus?
First, I remember that portal hypertension leads to the formation of collateral circulation. The lower esophagus is a common site for varices. The veins in this area typically drain into the systemic circulation through the azygos vein. But the question is specifically about the vein that drains into the portal vein. Wait, the lower esophageal veins themselves are part of the portal system. So the vein from the lower esophagus that connects to the portal vein is the left gastric vein. The left gastric vein is part of the portal venous system and drains into the portal vein. However, when there's portal hypertension, the left gastric vein can develop dilated veins, leading to varices. But the question is about the vein that drains into the portal vein, not the one that connects to the systemic circulation. Wait, no—the left gastric vein itself is a tributary of the portal vein, right? The lower esophageal veins (which are part of the systemic circulation) connect to the left gastric vein through the periesophageal veins. So the left gastric vein is the one draining into the portal vein from the lower esophagus. Therefore, the correct answer would be the left gastric vein.
Now, for the options. If the options included left gastric vein, that's the answer. Let's say the options are A: Left gastric vein, B: Right gastric vein, C: Splenic vein, D: Superior mesenteric vein. Then A would be correct. The right gastric vein drains into the portal vein but is from the upper stomach, not the lower esophagus. The splenic vein is a tributary of the portal vein but doesn't come from the esophagus. The superior mesenteric vein drains the small intestine. So the left gastric vein is the correct one here. The incorrect options would be other veins that either drain into the portal vein but aren't from the esophagus or are part of the systemic system. For example, the azygos vein drains into the systemic circulation, not the portal. So in a patient with portal hypertension, the left gastric vein is the one that's involved in the portal system, leading to varices when there's increased pressure. The key point is that the left gastric vein is the main tributary from the lower esophagus to the portal vein.
**Core Concept**
The lower esophagus is drained by the left gastric vein, which directly connects to the portal venous system. Portal hypertension causes collateral circulation between the portal and systemic veins, but the question specifically asks about the vein draining *into* the portal vein, not those forming collaterals.
**Why the Correct Answer is Right**
The **left gastric vein** (also called the coronary vein) is the primary vein draining the lower esophagus and upper stomach. It ascends along the lesser curvature of the stomach and drains into the portal vein. In portal hypertension, increased pressure in the left gastric vein leads to the formation of **esophageal varices** via anastomoses with the a