Which muscle pump is responsible for the majority of venous volume ejection?

• A. Foot muscle pump
• B. Calf muscle pump
• C. Thigh muscle pump
• D. Arm muscle pump

Answer: (B)

The calf muscle pump is primarily responsible for the majority of venous volume ejection in the body. This mechanism operates through the contraction and relaxation of the calf muscles during activities such as walking or standing. When the calf muscles contract, they compress the deep veins of the legs, which helps to propel blood upward toward the heart. This action is crucial for counteracting the effects of gravity and ensuring efficient venous return, particularly from the lower extremities. The anatomical positioning and the volume of muscle surrounding the deep veins in the calf region make this pump particularly effective in moving blood through the venous system. In contrast, other muscle pumps, such as those in the foot, thigh, or arm, do not exert the same level of influence on venous return as the calf muscle pump does.