Which muscle pump contributes least to the overall venous pumping action?

The thigh muscle pump contributes the least to the overall venous pumping action compared to the other options. In venous return, the calf muscle pump is particularly significant, as it actively facilitates blood flow back to the heart when the calf muscles contract during movements such as walking and standing. The foot muscle pump also plays a role by assisting in venous return, especially during activities involving the feet.

The arm muscle pump, while generally less impactful than the lower extremity muscle pumps due to its distance from the heart and the lower volume of blood it returns, still provides some assistance in venous return, especially during arm movements. In contrast, while the thigh muscles can support venous return, they do not have the same pumping advantage that the calf and foot muscles provide because they are farther from the heart and often engage less actively during typical daily movements compared to the calves and feet. Consequently, the contribution of the thigh muscle pump to venous return is lower than that of the other muscle groups listed.