Which vein returns blood to the right atrium from the upper half of the body?

The superior vena cava is the vessel responsible for returning deoxygenated blood from the upper half of the body to the right atrium of the heart. It collects blood from the head, neck, arms, and upper chest, effectively funneling it back to the heart to be replenished with oxygen in the lungs. This process is essential for maintaining proper circulation and ensuring that oxygen-poor blood is routed efficiently to where it can receive oxygen.

In contrast, the inferior vena cava primarily carries blood from the lower parts of the body, while the radial vein and femoral vein are more specific to certain regions. The radial vein drains blood from the forearm and hand, and the femoral vein is responsible for blood return from the thigh and leg. Neither the radial vein nor the femoral vein have any role in draining blood from the upper body, making them irrelevant to the question of which vein returns blood to the right atrium from the upper half of the body.