When legs veins stretch and create the pain?send me the process to make sure normal

Chronic venous insufficiency occurs when your leg veins don't allow blood to flow back up to your heart. Normally, the valves in your veins make sure that blood flows toward your heart. But when these valves don't work well, blood can also flow backwards. This can cause blood to collect (pool) in your legs.

a1 = unhealthy

a2= healthy

a3= healthy

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