Stefano Ricci
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Abstract The Authors studied 400 limbs of 200 non-embalmed cadaveric subjects (mean age of 84). After ligation of the femoral vein, green neoprene latex was injected (about 120 to 150 mL per limb), over 30 min. Dissection was started the next day; in some cases, an iodine contrast agent was added to the latex injection and, prior to dissection, a multislice helical CT performed.- The medial and mostly lateral plantar veins converge into the plexus-shaped calcaneal crossroad, where the blood is ejected upwards into the two posterior tibial veins. In addition, several medial perforators of the foot directly connect the deep system (medial plantar veins) to the superficial venous system (medial marginal vein). A venous reservoir of 25 mL of blood is mobilized upwards with each step during walking. - The calf veno-muscular pump is the most important pump in the limb. It consists on the leg pump, located in the veins of the soleus, and the popliteal pump located in the gastrocnemius muscle. The gastrocnemius and soleus together form a muscular mass that is occasionally described as the Triceps suræ; its tendon of insertion is the tendo calcaneous (tendo Achillis). It is the thickest and strongest tendon in the body. - The drainage of the veins of the soleus is divided into two parts: the medial veins horizontally oriented into the posterior tibial veins and the lateral veins, vertically into the fibular veins. - The gastrocnemius is the most superficial muscle, and forms the greater part of the calf. It arises by two heads, which are connected to the condyles of the femur by strong, flat tendons. The muscular veins of gastrocnemius (mainly the medial ones) have two main characteristics: - They consist of several pedicles of longitudinal veins appearing at the lower part of the muscle as a continuation of the polar perforators of the calf. - They join upwards in a unique collector ending into the popliteal vein. The medial gastrocnemial veins are the larger ones, with two to four pedicles of one or two veins. The pedicles originate from a network of veins connected to several calf perforators. When present, the medial gastrocnemial collector frequently makes a common trunk (about 30%) with the SSV. The power of the pump is explained by the unique collector draining into the popliteal vein, producing a high-speed ejection of blood during the contraction of the gastrocnemius muscle. - Concerning the thigh pumps, posteriorly, the biceps and particularly the semimembranosus muscles have important venous arcades in shape of a plexus. The semimembranosus muscle is located at the posterolateral aspect of the thigh. A number of the venous arcades are located inside the muscle, which constitutes the main pump of the posterior thigh; they have a number of anastomoses with the popliteal axis and drain proximally into the deep femoral vein, a safety valve on the femoral vein axis, shunting the narrowed part created by the Hunter’s outlet. In fact, the flush of the gastrocnemial pump is so powerful that the popliteal vein cannot accommodate the whole flux of the blood if there is a stenosis or a simple narrowing of the Hunter’s canal. In such cases, a part of the outflow can be absorbed by the semimembranosus pump, and drained via the deep femoral vein. - The quadriceps femoris includes four muscles on the front of the thigh. The muscular veins of this big mass drain mainly into a big trunk ending at the root of the thigh into the common femoral vein. The synchronization of the different veno-muscular pumps during walk is crucial: foot, then leg, popliteal and finally thigh pumps. The dynamic effect of the venous pumps is closely related to the anatomy of the venous valves. The anatomical knowledge of the veno-muscular pumps, and particularly the calf pump, is crucial to better understand their major role in venous return. This knowledge helps explain the impact of ankle stiffness, which impairs the calf pump activation. |
Comment by Stefano Ricci
All phlebologists should deserve special gratitude to this anatomy School (Gillot-Uhl) that has, nowadays, no comparable examples. It is impossible to make a summary of such an important paper, the details of the limb veins description being more important than the general aspects. Moreover, the text is correlated to an exceptionally rich iconography that needs to be directly explored to be enjoyed. While some concepts are not new (leg pumps), special interest is related to the analysis of the muscle veins orientation (vertical for medial/horizontal for lateral), which should correspond to a special hemodynamic mechanism that is still not clear. Thigh pumps are a new input in our knowledge, in particular the one concerning the semimembranous muscle as a safety valve when Hunter’s canal is unable to receive the powerful ejection of the calf pump. This event (virtual femoral obstruction) could also concern the Giacomini vein (GV) development or, more, the transmission of a systolic sapheno-popliteal reflux via the GV into the GSV stream to join the Femoral vein. There are however two limitations in this excellent paper:
- The complete absence of a correlation between anatomy and ultrasound imaging, not allowing a more complete application of the given data to the clinical everyday experience.
- Limited hemodynamic evidences of pumps mechanisms (pressures measurements) to accompany the anatomy findings.
Finally, it would be interesting to understand the foot pump function: being stated that the most powerful pump is the one of the calf, how the foot pump insufficiency (ankle stiffness) condition the limb venous return?
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