During contraction, which statement about perforator valves is true?

• A. Perforator valves close, preventing flow into superficial system
• B. Perforator valves open, allowing flow into superficial system
• C. Perforator valves reverse direction
• D. Perforator valves do not change

Answer: (A)

Perforator valves regulate the direction of blood flow between the superficial and deep venous systems and act to protect the superficial veins during leg muscle activity. When the calf muscles contract, the deep veins are compressed and pressure rises; if the valve were open, this could push blood into the superficial veins, causing pooling and defeating the calf pump. To prevent that, the perforator valves close during contraction, blocking flow into the superficial system. When the muscles relax, the valves open and allow blood to move from the superficial veins into the deeper system, where it can be propelled proximally toward the heart. This unidirectional control helps maintain efficient venous return and prevents reflux.