The inferior vena cava is formed at approximately which vertebral level?

• A. L4
• B. L5
• C. L3
• D. T12

Answer: (B)

The main idea is where the big venous trunk that returns blood from the lower body is formed. The inferior vena cava comes together from the two common iliac veins at about the fifth lumbar vertebra. This junction is just to the right of the midline, behind the right psoas muscle. From there, the IVC ascends on the right side of the vertebral column and eventually reaches the heart by passing through the diaphragm at the caval opening near T8.

This formation level makes sense because each iliac vein drains the corresponding lower limb and pelvis, and their union at roughly L5 creates the single conduit that then collects blood from portions of the trunk and abdomen as it goes upward. The other levels listed don’t correspond to the point where the common iliac veins fuse: the aorta typically bifurcates around L4, and higher levels like L3 or T12 don’t mark the formation of the IVC.