From the Guidelines
No, there is no tendon in the ankle area that serves as a pump to help the heart. The concept of a "pump" in the context of assisting the heart is more accurately attributed to the action of muscles, particularly the calf muscles in the lower leg, which compress veins during contraction to facilitate venous return to the heart 1. This mechanism is often referred to as the "skeletal muscle pump" or "calf muscle pump". Tendons, on the other hand, are connective tissues that link muscles to bones, enabling movement by transmitting the force generated by muscle contraction. They do not possess the capability to pump blood. The Achilles tendon, located in the ankle area, is a prime example; it connects the calf muscles to the heel bone, playing a crucial role in movement and stability but not in the circulation of blood. The return of blood from the lower extremities to the heart is primarily facilitated by the heart itself, assisted by one-way valves in the veins and the contraction of muscles, which helps to prevent backflow and ensure efficient blood circulation 1.
Key points to consider:
- The primary mechanism for blood circulation is the heart's pumping action.
- Muscles, particularly in the lower legs, assist in venous return through contraction.
- Tendons, such as the Achilles tendon, are involved in movement and stability, not in pumping blood.
- The efficient return of blood to the heart is facilitated by a combination of the heart's action, one-way valves in veins, and muscle contractions. The evidence from the study by Prandoni et al, as mentioned in 1, highlights the importance of venous obstruction and valvular competence in the development of postthrombotic syndrome, further emphasizing the role of the venous system and muscle pump in assisting, but not replacing, the heart's function.
From the Research
Tendon in the Ankle Area Serving as a Pump
- There is no direct evidence of a tendon in the ankle area that serves as a pump to help the heart. However, the musculovenous pump in the lower limb plays a crucial role in venous return 2.
- The foot pump is considered the starter of venous return, and the calf pump is the most powerful pump in the lower limb, divided into two anatomical parts: the leg pump and the popliteal pump 2.
- The musculovenous pump creates a chain of events by its successive activation during walking, acting like a peripheral heart to avoid gravitational reflux during muscular diastole 2.
- The pedal musculovenous pump activation can effectively counteract the negative impact of knee flexion on human popliteal venous flow 3.
Mechanism of Venous Return
- Venous return is the flow of blood from the systemic venous network towards the right heart, and it equals cardiac output at steady state 4.
- The mean systemic filling pressure, right atrial pressure, and resistance to venous return are the three determinants of venous return, as described by Guyton's model 4.
- The musculovenous pump does not generally have an edema-protective effect, but rather muscle contractions activate mechanisms that stimulate the extravasation of fluid 5.
Age-Related Changes in Musculovenous Pump
- Senescence does not alter the venous system itself, but extravascular factors such as muscles, understanding, and coordination of motions, and articular flexibility influence the performance of the musculovenous pump 6.
- The values measured in the elderly group are in the range of normal values when a passive massage of the calf is substituted for ankle flexions, highlighting the importance of muscular and articular activity in elderly people 6.