Inferior Vena Cava Anatomy
The inferior vena cava is formed at the level of the fifth lumbar vertebra, a little to the right of the midline (Fig. 4.91). It ascends the posterior abdominal wall and pierces the central tendon of the diaphragm to enter the thorax at the level of the eighth thoracic vertebra (Fig. 4.92).
Behind the inferior vena cava lie the lumbar vertebral bodies, the anterior longitudinal ligament, the right sympathetic chain and right psoas major muscle. In addition, the right renal and right lumbar arteries cross behind the vena cava (Figs 4.88 & 4.89) and most of the right suprarenal gland lies posterior to the vessel (Fig. 4.92).
Near its commencement, the inferior vena cava is covered anteriorly by peritoneum and coils of small intestine. Superiorly, it is crossed by the root of the mesentery, the right gonadal artery (Fig. 4.88) and the third part of the duodenum (Fig. 4.52). It continues behind the omental foramen (Fig. 4.38) and then grooves the posterior surface of the liver (Fig. 4.58) before piercing the diaphragm.
To the right of the vena cava lie the gonadal vessels, the ureter, the kidney and renal vessels (Fig. 4.91) and the right lobe of the liver. To the left lie the aorta with its associated lymph nodes, the right crus of the diaphragm and the caudate lobe of the liver.
The venous drainage of the suprarenal glands, the kidneys and the gonads is asymmetric. On the right, each of these organs is drained by a vein that passes directly into the inferior vena cava (Figs 4.91 & 4.92) but on the left, the renal vein receives the suprarenal and gonadal veins before crossing in front of the aorta to reach the vena cava. Immediately before its passage through the diaphragm the inferior vena cava receives several large hepatic veins (Fig. 4.92).
The parietal tributaries of the inferior vena cava drain the diaphragm and the posterior pelvic and abdominal walls. The lumbar and median sacral veins (Figs 4.88 & 4.90) accompany the corresponding arteries, the upper lumbar veins often communicating with the renal, suprarenal, azygos and hemiazygos veins. Two or more inferior phrenic veins drain the undersurface of the diaphragm (Fig. 4.92).