What is the primary cause of deep vein thrombosis in the lower extremities?

The primary cause of deep vein thrombosis (DVT) in the lower extremities is prolonged immobility leading to venous stasis. When a person remains inactive for extended periods, such as during long flights, bed rest, or sedentary jobs, blood flow in the veins can slow down significantly. This sluggish movement can lead to the formation of clots, as the blood is less likely to be propelled through the veins effectively.

Venous stasis creates an environment conducive to clot formation because it allows blood to pool in the veins, particularly in the lower extremities where there is more dependency. Additionally, factors such as damage to the blood vessel walls and changes in blood composition may also play a role in clot development, but the critical first step that sets the stage for DVT is that prolonged immobility.

In contrast, increased physical activity promotes blood circulation and helps prevent stasis, while high levels of hydration can dilute the blood and enhance flow, further reducing the risk of clot formation. As for aged blood cells, while they can affect circulation over time, they are not a direct cause of DVT. Thus, the link between immobility and venous stasis is the reason this option is recognized as the primary cause of