Okay, let's tackle this question about the hemiazygos vein. The question is asking which statement is NOT true. The user didn't provide the options, but I need to figure out the common facts about the hemiazygos vein to determine the correct answer.

First, I should recall the anatomy of the hemiazygos vein. The hemiazygos vein is part of the azygos system, which drains deoxygenated blood from the thoracic wall. It arises from the left ascending lumbar vein and ascends along the left side of the thoracic vertebrae. It typically drains into the azygos vein, which then connects to the superior vena cava.

Now, considering possible options that might be incorrect. Common misconceptions or facts that are often confused include its drainage into the inferior vena cava (which is incorrect because it drains into the azygos vein), its origin from the left ascending lumbar vein (correct), and its course along the left side (correct). Another point is that it's connected to the accessory hemiazygos vein, which drains into the left renal vein, but that's a different structure.

If an option states that the hemiazygos vein drains into the inferior vena cava, that would be incorrect. Another incorrect statement might be about its origin from the right ascending lumbar vein instead of the left. Also, if an option says it runs on the right side, that's wrong. So the incorrect statement would be the one that contradicts these points.

The clinical pearl here is to remember the azygos system's role in collateral circulation, especially in portal hypertension. The hemiazygos vein is important in connecting the portal and systemic venous systems through the esophageal veins. So, understanding its anatomy is crucial for conditions like variceal bleeding.

**Core Concept**
The hemiazygos vein is a key component of the azygos venous system, draining deoxygenated blood from the posterior thoracic wall. It originates from the **left ascending lumbar vein**, ascends along the **left side of the thoracic vertebral column**, and typically drains into the **azygos vein**, which connects to the superior vena cava.

**Why the Correct Answer is Right**
The hemiazygos vein **does NOT drain into the inferior vena cava** (IVC). Instead, it connects to the azygos vein in the thorax (usually at the T8-T9 level). This distinction is critical for understanding venous drainage patterns and collateral circulation in conditions like portal hypertension, where the azygos system may form portosystemic anastomoses.

**Why Each Wrong Option is Incorrect**
**Option A:** If claiming the hemiazygos vein drains into the IVC, this is incorrect because it connects to the azygos vein, not the IVC.
**Option B:** If stating it arises from the **right** ascending lumbar vein, this is incorrect; it originates from the **left** ascending lumbar vein.
**Option C:** If describing it as running on the **right** side of the vertebral column, this is wrong—it runs on the **left** side.
**Option D:** If asserting it terminates in the **portal vein**, this is incorrect, as it terminates in the azygos vein

✓ Correct Answer: A. Formed by right lumbar azygos and right ascending lumbar veins