The right and left brachiocephalic veins are formed posterior to the sternoclavicular (SC) joints by the union of the internal jugular and subclavian veins. At the level of the inferior border of the 1st right costal cartilage, the brachiocephalic veins unite to form the SVC (Figs. 1.65B and 1.66B). The left brachiocephalic vein is more than twice as long as the right brachiocephalic vein because it passes from the left to the right side, anterior to the roots of the three major branches of the arch of the aorta (Fig. 1.66B). The brachiocephalic veins shunt blood from the head, neck, and upper limbs to the right atrium.

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Most veins in the anterior cervical region are tributaries of the IJV, typically the largest vein in the neck (Figs. 8.15 and 8.20). The IJV drains blood from the brain, anterior face, cervical viscera, and deep muscles of the neck. It commences at the jugular foramen in the posterior cranial fossa as the direct continuation of the sigmoid sinus (see Chapter 7).

The IJV ends posterior to the medial end of the clavicle by uniting with the subclavian vein to form the brachiocephalic vein. This union is commonly referred to as the venous angle and is the site where the thoracic duct (left side) and the right lymphatic trunk (right side) drain lymph collected throughout the body into the venous circulation (see Fig. 8.48). Throughout its course, the IJV is enclosed by the carotid sheath (Fig. 8.21).

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The subclavian vein, the continuation of the axillary vein, begins at the lateral border of the 1st rib and ends when it unites with the IJV (Fig. 8.24A). The subclavian vein passes over the 1st rib anterior to the scalene tubercle parallel to the subclavian artery, but it is separated from it by the anterior scalene muscle. It usually has only one named tributary, the EJV (Fig. 8.20).

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The superior vena cava (SVC) returns blood from all structures superior to the diaphragm, except the lungs and heart. It passes inferiorly and ends at the level of the 3rd costal cartilage, where it enters the right atrium of the heart. The SVC lies in the right side of the superior mediastinum, anterolateral to the trachea and posterolateral to the ascending aorta. The right phrenic nerve lies between the SVC and the mediastinal pleura. The terminal half of the SVC is in the middle mediastinum, where it lies beside the ascending aorta and forms the posterior boundary of the transverse pericardial sinus (Fig. 1.46).

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The pulmonary trunk, approximately 5 cm long and 3 cm wide, is the arterial continuation of the right ventricle and divides into right and left pulmonary arteries. The pulmonary trunk and arteries conduct low-oxygen blood to the lungs for oxygenation (Figs. 1.49A and 1.52B).

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The veins of the posterior abdominal wall are tributaries of the IVC, except for the left testicular or ovarian vein, which enters the left renal vein instead of entering the IVC (Fig. 2.99). The IVC, the largest vein in the body, has no valves except for a variable, non-functional one at its orifi ce in the right atrium of the heart. The IVC returns poorly oxygenated blood from the lower limbs, most of the back, the abdominal walls, and the abdominopelvic viscera. Blood from the abdominal viscera passes through the portal venous system and the liver before entering the IVC via the hepatic veins.

The inferior vena cava (IVC) begins anterior to the L5 vertebra by the union of the common iliac veins. The union occurs approximately 2.5 cm to the right of the median plane, inferior to the aortic bifurcation and posterior to the proximal part of the right common iliac artery (see Fig. 2.76). The IVC ascends on the right side of the bodies of the L3–L5 vertebrae and on the right psoas major to the right of the aorta. The IVC leaves the abdomen by passing through the caval opening in the diaphragm and enters the thorax at the T8 vertebral level. Because it is formed one vertebral level inferior to the aortic bifurcation, and traverses the diaphragm four vertebral levels superior to the aortic hiatus, the overall length of the IVC is 7 cm greater than that of the abdominal aorta, although most of the additional length is intrahepatic. The IVC collects poorly oxygenated blood from the lower limbs and non-portal blood from the abdomen and pelvis. Almost all the blood from the gastrointestinal tract is collected by the hepatic portal system and passes through the hepatic veins to the IVC.

The tributaries of the IVC correspond to the paired visceral and parietal branches of the abdominal aorta. The veins that correspond to the unpaired visceral branches of the aorta are instead tributaries of the hepatic portal vein. The blood they carry does ultimately enter the IVC via the hepatic veins, after traversing the liver.

The branches corresponding to the paired visceral branches of the abdominal aorta include the right suprarenal vein, the right and left renal veins, and the right gonadal (testicular or ovarian) vein. The left suprarenal and gonadal veins drain indirectly into the IVC because they are tributaries of the left renal vein.

Paired parietal branches of the IVC include the inferior phrenic veins, the 3rd (L3) and 4th (L4) lumbar veins, and the common iliac veins. The ascending lumbar and azygos veins connect the IVC and SVC, either directly or indirectly providing collateral pathways (see the blue box “Collateral Routes for Abdominopelvic Venous Blood” on p. 319).

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Several renal veins drain each kidney and unite in a variable fashion to form the right and left renal veins; these veins lie anterior to the right and left renal arteries. The longer left renal vein receives the left suprarenal vein, the left gonadal (testicular or ovarian) vein, and a communication with the ascending lumbar vein; it then traverses the acute angle between the SMA anteriorly and the aorta posteriorly (see the blue box “Renal Vein Entrapment Syndrome” on p. 298). Each renal vein drains into the IVC.