In case of IVC obstruction the collaterals which open up are all except ?
**Core Concept**
In the event of Inferior Vena Cava (IVC) obstruction, the body attempts to compensate for the loss of venous return by opening up collateral venous pathways. These collateral pathways involve the anastomoses between the veins of the upper and lower body.
**Why the Correct Answer is Right**
The correct answer involves understanding the anatomy of the venous system and the collateral pathways that open up in case of IVC obstruction. The superior epigastric and inferior epigastric veins form anastomoses between the internal thoracic vein and the external iliac vein, respectively. Similarly, the azygos and ascending lumbar veins form a collateral pathway between the superior and inferior vena cava. The lateral thoracic veins and prevertebral veins also contribute to the collateral circulation. However, the superficial epigastric and iliolumbar veins are not typically involved in the collateral pathways that open up in case of IVC obstruction.
**Why Each Wrong Option is Incorrect**
**Option A:** The superior epigastric and inferior epigastric veins are indeed involved in the collateral pathways that open up in case of IVC obstruction, making this option incorrect.
**Option B:** The azygos and ascending lumbar veins do form a collateral pathway between the superior and inferior vena cava, making this option incorrect.
**Option D:** The lateral thoracic veins and prevertebral veins do contribute to the collateral circulation, making this option incorrect.
**Clinical Pearl / High-Yield Fact**
In case of IVC obstruction, the increased pressure in the lower body leads to the opening up of collateral pathways, which can be visualized on imaging studies such as ultrasound or CT scans. Recognizing these collateral pathways is essential for diagnosing and managing IVC obstruction.
**✓ Correct Answer: C. Superficial epigastric & iliolumbar vein**