Final answer:
The inferior vena cava passes through the diaphragm before emptying into the right atrium of the heart.
Step-by-step explanation:
The inferior vena cava passes through the diaphragm, a major muscle, in order to enter into the right atrium of the heart. The diaphragm serves as a physical barrier beneath which systemic venous blood from areas inferior to it, such as the lower limbs and the abdominopelvic region of the body, enters the inferior vena cava. The inferior vena cava is a large systemic vein that ultimately drains this deoxygenated blood into the right atrium, completing the systemic circulation loop and allowing this blood to travel towards the lungs for reoxygenation.