Chapter 13: Vessles and lympatic drainage of the lower limb
The chief superficial veins are the great and small saphenous veins. The great (or long) saphenous vein (fig. 13-1) begins on the medial side of the dorsal venous network of the foot. It ascends about a finger breadth anterior to the medial malleolus, where it can be found for catheterization. It crosses the medial surface of the tibia obliquely, passes posterior to the medial condyles of the tibia and femur, and then ascends along the medial side of the thigh. In the femoral triangle, it pierces the cribriform fascia (at the saphenous opening) and the femoral sheath, ending in the femoral vein. A varicose vein is one that has permanently lost its valvular efficiency, a condition that is not uncommon in the great saphenous vein, which is frequently tortuous and dilated when a subject is in the erect position. The great saphenous vein receives many tributaries, including the superficial epigastric vein. Communications occur between the superficial epigastric vein and lateral thoracic veins (by way of the thoraco-epigastric vein). Therefore, there is a communication between the femoral and the axillary veins. These communications are important, and they become enlarged in the event of obstruction of either the superior or inferior vena cava.
The small (or short) saphenous vein begins on the lateral side of the dorsal venous network of the foot. It passes posteror to the lateral malleolus and ascends the posterior leg. It then passes between the heads of the gastrocnemius, pierces the fascia of the popliteal fossa, and ends variably in the popliteal, great saphenous, or some muscular veins (fig. 13-1).
The chief deep veins of the lower limb are the femoral and the popliteal veins (figs. 13-1 and 13-2). The deep veins begin on the plantar aspect of the foot and accompany the anterior and posterior tibial arteries and the fibular artery. Many valves are present. Most of the blood from the lower limb is returned by way of the deep veins, and alternate routes exist even when the femoral vein is ligated. The superficial veins can be obliterated without seriously affecting the circulation, provided that the deep veins remain intact.
The superficial and deep veins are connected by perforating veins (figs. 13-1 and 13-3). An important series is found in the leg, where valves direct blood from superficial to deep veins. Muscular action, combined with the arrangement of the valves, is important in returning blood from the lower limb, and venous return is much reduced during quiet standing, when blood pooling may result in hypotension.
The superficial lymphatic vessels of the lower limb are arranged as medial trunks, which end in the inguinal nodes, and as a lateral set, which either joins the medial trunks superior to the knee or ends in the popliteal nodes (fig. 13-4). The popliteal nodes receive the deep lymphatic trunks that accompany the tibial blood vessels and the lateral group of superficial trunks. Their efferents accompany the femoral blood vessels to the deep inguinal nodes. The inguinal nodes are mostly subcutaneous and are frequently palpable in vivo. The superficial inguinal nodes lie both longitudinally along the great saphenous vein and transversely, just inferior to the inguinal ligament, whereas the deep inguinal nodes (into which the superficial drain) lie medial to the femoral vein. The subdivision into superficial and deep groups, however, is not clinically important. When the inguinal nodes are found to be enlarged, their territory of drainage, i.e., the trunk inferior to the level of the umbilicus (including perineum, external genitalia, and anus) as well as the entire lower limb should be examined. The efferent lymphatic vessels from the inguinal nodes proceed to the external iliac nodes and drain ultimately into the lumbar (aortic) nodes.
The main artery carrying blood to the lower limb is named successively external iliac, femoral, and popliteal. The arrangement of this vessel and its branches is summarized in figure 13-5. The external iliac artery passes deep to the inguinal ligament and is then termed the femoral artery. The principal branch of this artery in the proximal thigh is the deep femoral. Femoral circumflex arteries either arise from the femoral or deep femoral artery and pass posteriorward around the hip joint to supply this joint and to contribute to an anastamosis with gluteal and posterior thigh vessels. The blood supply of the posterior thigh arises from perforating branches from the deep femoral artery. In the lower third of the thigh, the femoral artery passes posteriorward (through the adductor opening), where its name is changed to popliteal. This artery gives rise to several genicular braches around the knee. Inferior to the knee joint (at the inferior border of the popliteus muscle), the popliteal artery divides into the anterior and posterior tibial arteries. The posterior tibial artery gives off the fibular artery from its lateral side and, as it passes posterior to the medial malleolus, divides into medial and lateral plantar arteries, and the lateral plantar artery forms the plantar arch. The anterior tibial artery supplies the anterior leg and continues onto the dorsum of the foot as the dorsal artery of the foot (see fig. 17-4C).
Dodd, H., and Cockett, F. B., The Pathology and Surgery of the Veins of the Lower Limb, 2nd ed., Churchill Livingstone, Edinburgh, 1976. Chapter 3 is devoted to the surgical anatomy of the veins.
13-1 Where are frequent sites for varicose veins?
13-2 What is the clinical importance of thoraco-epigastric venous connections?
13-3 What should be examined when inguinal lymph nodes are found to be enlarged?
13-4 What is meant by collateral circulation?
13-5 When a catheter is inserted in the thigh, how does it reach the vessels of the neck for cerebral angiography?
Figure 13-1 A simplified representation of the superficial veins of the lower limb. The major tributaries and also the major communicating veins superior to the ankle are shown according to Dodd and Cockett. Details of the veins of the foot have been omitted.
Figure 13-2 Normal venograms showing (right) the deep veins of the leg, the popliteal vein, the great saphenous vein, and (left) the femoral and deep femoral veins. Note the slight bulges at the valves, in some of which the cusps can be distinguished. (Courtesy of G. M. Stevens, M.D., Palo Alto Medical Clinic, Palo Alto, California.)
Figure 13-3 Schematic representation of venous circulation. The changes in venous pressure during exercise are such that nearly all blood returns by way of the deep veins, which receive blood from superficial veins by way of the communicating veins superior to the ankle.
Figure 13-4 Schematic representation of the lymphatics of the lower limbs. The two lower arrows in the figure on the left indicate that the popliteal nodes receive both superficial and deep lymphatic vessels.
Figure 13-5 The arteries of the lower limb.