Veins of the lower extremity (Figure 37–1) consist of superficial and deep systems joined by venous perforators. The great and small saphenous veins are superficial veins (the name “saphenous” aptly derived from the Greek word for “manifest, clear,” or “visible”). They contain many valves and show considerable variation in their location and branching points. The great saphenous vein may be duplicated in up to 10% of patients. Typically, it originates from the superficial arch of the foot and is found anterior to the medial malleolus at the ankle. As it ascends in the calf just beneath the superficial fascia, it is joined by two major tributaries: an anterior vein, which crosses the tibia; and a posterior arch vein, which arises posterior to the medial malleolus beside the posterior tibial artery. The great saphenous vein then enters the fossa ovalis in the groin to empty into the deep femoral vein.
Anatomy of the superficial and perforating veins of the lower extremity.
The saphenofemoral junction is marked by four or five prominent branches of the great saphenous vein: the superficial circumflex iliac vein, the external pudendal vein, the superficial epigastric vein, and the medial and lateral accessory saphenous veins. Another important anatomic landmark is the relationship of the great saphenous vein to the saphenous branch of the femoral nerve; as it emerges from the popliteal space, the nerve follows a course parallel to the vein. Injury during saphenous vein harvest for bypass produces neuropathic pain or numbness along the medial calf and foot. The small saphenous vein arises from the superficial dorsal venous arch behind the lateral malleolus at the ankle and curves toward the midline of the posterior calf, ascending to join the popliteal vein behind the knee.
Deep veins of the leg parallel the courses of the arteries. Two or three venae comitantes accompany each tibial artery. At the knee, these paired high-capacitance veins merge to form the popliteal vein, which continues proximally as the femoral vein. At the inguinal ligament, the femoral and deep (profunda) femoral veins join medial to the femoral artery to form the common femoral vein. Proximal to the inguinal ligament, the common femoral vein becomes the external iliac vein. In the pelvis, external and internal iliac veins join to form common iliac veins that empty into the inferior vena cava (IVC). The right common iliac vein ascends almost vertically to the IVC, whereas the left common iliac vein takes a more transverse course. For this reason, the left common iliac vein may be compressed between the right common iliac artery and lumbosacral spine, a condition known as May-Thurner syndrome when thrombosis of the left iliac vein occurs.
Muscular sinusoids represent another component of the deep veins of the leg. These thin-walled, ...