The principal return of blood flow of the lower extremities is through the deep veins. In the leg, the anterior tibial, posterior tibial, peroneal, and gastrocnemius veins join forming the popliteal vein at the popliteal fossa, ascending into the thigh, and becoming the femoral vein. In the groin, the femoral vein is joined by the deep femoral vein which enters the abdomen underneath the inguinal ligament becoming the external iliac vein [1].

The superficial venous system consists of two axial veins: the great saphenous vein (GSV) and the small saphenous vein (SSV) . Several epifascial veins connect the great saphenous vein and the small saphenous vein system. The posterior thigh circumflex vein, previously referred to as Giacomini’s vein, originates from the SSV or its thigh extension. It ends into the GSV or the posterior accessory vein [2, 3].

The great saphenous vein begins at the dorsum of the foot and ascends anterior to the medial malleolus at the ankle and anteromedial to the tibia. At the knee, the vein is in the medial aspect of the popliteal fossa and ascends in the anteromedial aspect of the thigh, joining the femoral vein in the groin through an opening of the superficial fascia called the fossa ovalis.

The saphenofemoral junction is a complex anatomic entity composed of one or several external pudendal veins, the superficial epigastric vein, the superficial circumflex vein, and one or several accessory saphenous veins, whose course in the leg can be anterior and posterior to the GSV [1]. The terminal valve and the preterminal valve are located at the saphenofemoral junction and a few millimeters distally (Fig. 38.2) [1–3].

Anatomic specimens and ultrasound technology have documented the GSV within a saphenous compartment , whose boundaries are the more superficial saphenous fascia and deeply by the muscular fascia of the limb (Fig. 38.3) [2, 3].

The small saphenous vein originates laterally from the dorsal venous arch of the foot and travels subcutaneously behind the lateral malleolus at the ankle. It ascends the calf in its own compartment between the heads of the gastrocnemius muscle to join the popliteal vein in the popliteal fossa [1]. Posterior and anterior accessory saphenous veins are present in the leg.

At several levels in the leg, and into the thigh, perforating veins connect the superficial and deep venous systems. The perforating veins are currently identified measuring the distance in centimeters from the heel. Names such as Hunterian, Dodd, and Cockett perforating veins are considered obsolete (Table 38.1) [2, 3].

The external iliac veins course in the pelvic retroperitoneal space, along the brim. Tributaries of the external iliac veins are the deep inferior epigastric, circumflex, and pubic veins. At the level of the sacroiliac joint, the external iliac veins join the internal veins forming the common iliac veins. The internal iliac veins drain from extrapelvic and intrapelvic tributaries. The common iliac veins of each side join into the inferior vena cava on the right side of the vertebral columns at the level of the fifth vertebral body. The right iliac artery crosses the origin of the left common iliac vein at the level of the fifth lumbar vertebral body. The inferior vena cava ascends on the right side of the spine and terminates in the right atrium. Tributaries are the lumbar, gonadal, renal, adrenal, inferior epiphrenic, and hepatic veins.

In the upper extremity, a superficial and deep venous system can be identified. Superficial veins of the upper extremity are the cephalic and basilic veins. The cephalic vein originates from the dorsal venous plexus on the radial side, while the basilic vein originates from the same plexus on the ulnar side. The cephalic vein ascends the lateral side of the arm and empties into the axillary vein through the infraclavicular fossa, perforating the clavipectoral fascia [4]. The basilic vein ascends the medial aspect of the arm and joins the axillary vein, after receiving the brachial vein. Several veins connect the cephalic and the basilic veins including the antecubital vein. The deep veins are the radial, ulnar, brachial, and axillary veins and are paired with the homonymous arteries.

At the lateral border of the first rib, the axillary vein becomes the subclavian vein [4]. At the medial border of the anterior scalene muscle, the subclavian vein forms the brachiocephalic vein with the internal jugular vein. Tributaries of the innominate vein are the vertebral, internal thoracic, and inferior thyroid veins. Behind the first right costal cartilage, the brachiocephalic veins from each side form the superior vena cava, whose course is to the right of the ascending aorta. Prior to entering the pericardium and emptying into the right atrium, the superior vena cava receives the azygos vein [4].

The azygos vein lies on the right side of the spine and originates at the level of the renal vein, sometimes as the cephalad extension of the ascending lumbar vein. Between the fourth and the sixth thoracic vertebrae, the azygos vein arches anteriorly, inferior to the right main bronchus, and empties into the superior vena cava. The hemiazygos has a similar origin but on the left side of the spine at the level of the eighth thoracic vertebra crosses the midline and empties into the azygos vein. The azygos and hemiazygos veins receive the subcostal and intercostal veins and anastomose with the paravertebral vein plexus [4].

The structure of the venous wall includes the intima, media, and adventitia. The intima enfolds forming bicuspid valves whose function is to assure venous return to the heart [4]. The dysfunction of venous valves is associated with acute and chronic venous disorders of the extremities.