An obstruction in the superior vena cava would decrease the flow of blood from the head and neck to the heart.

• A. True
• B. False
• C. Only during certain conditions
• D. Not applicable

Answer: (A)

The main idea here is that the superior vena cava is the main pathway carrying blood from the head and neck to the heart. If the SVC is obstructed, that drainage route is blocked, so less blood from those regions can reach the right atrium. Blood from the head and neck may try to find alternate routes through collateral veins like the azygos system or vertebral venous plexus, but these channels aren’t as capable as the SVC and often can’t fully compensate. As a result, venous return from the head and neck decreases, and pressure can build up in the upstream veins, leading to signs such as facial swelling and neck vein distention. So the statement that obstruction in the superior vena cava would decrease the flow of blood from the head and neck to the heart is correct.