Which vein returns blood to the heart?

The superior and inferior vena cava are major vessels responsible for returning deoxygenated blood from the body back to the heart. The superior vena cava collects blood from the upper body, including the head, neck, and arms, while the inferior vena cava brings blood from the lower body, including the abdomen and legs. Once this blood enters the heart, it flows into the right atrium, where it can be pumped to the lungs for oxygenation.

In contrast, the carotid artery is involved in transporting oxygenated blood from the heart to the brain and does not perform the function of returning blood to the heart. The pulmonary vein carries oxygenated blood from the lungs back to the left atrium of the heart, but it is not involved in returning blood from the body. The radial vein is smaller and primarily drains blood from the forearm into larger veins leading to the heart, but it is not one of the major vessels responsible for the overall return of blood to the heart like the vena cavae are.