Inferior suprarenal vena cava. Above the confluence of the right renal vein, at the level of L2, the inferior vena cava (IVC) lies on the right lateral portion of the spine, ascending with an oblique direction slightly to the right, and transverses the liver, partially embedded between the caudate and the right lobes. Finally the IVC penetrates the membranous portion of the diaphragm at the level of T8, with the inferior branch of the right phrenic nerve, and immediately drains into the right atrium.
Posteriorly the IVC is in relation with the right ascending lumbar vein, which passes the right crus of the diaphragm and joins the XII intercostal vein to form the external root of the azygous. In this portion of IVCit is uncommon, but possible, to find some posterior venous branches which, during the dissection for TVE, must be ligated in order to obtain a complete vascular exclusion of the liver. In the more cranial portion of the dorsal side of the IVC, just below its junction with the right hepatic vein and above the adrenal vein, there is the IVC ligament; this is a fibrous band connecting the dorsal edge of the right lobe of the liver (segment VIII) to the caudate lobe. Its identification and division is essential for safe exposure of the junction of the right hepatic vein to the IVC. In some cases, when at this level the IVC ligament is partially or totally substituted by a parenchimal band, the IVC runs intrahepatic and the dissection of the right hepatic vein can be more difficult.
The right side of the retrohepatic portion of the IVC is related to the medial part of the right adrenal gland. The right adrenal vein joins the IVC in this portion: exclusion (division or not) of this vein is essential during the TVE to avoid an incomplete exclusion of the liver.
The left side of the IVC is covered by peritoneum of the lesser sac, and is related to the right crus of the diaphragm and to the caudate lobe of the liver.
The anterior wall of the IVC between duodenum and caudate lobe is covered by peritoneum, lies in the posterior wall of the epiploic foramen, by which it is separated from the portal vein. The more cranial portion of the IVC transversing the liver is enfolded on three sides by liver parenchyma and receives several small branches draining directly from the caudate lobe (dorsal hepatic veins). The number of these veins is extremely variable (from 1 to 50); in more than 50% of cases there is more than one vein. Also the size of these dorsal veins is variable, and in 20% of cases there is a large inferior right hepatic vein.
Hepatic veins. The extraparenchimal portion of the hepatic veins is generally short; for this reason manoeuvres to achieve their extraparenchimal control can be dangerous, expecially in the case of enlarged liver or of big posterior tumors. The right hepatic vein joins the right antero-lateral side of the IVC in a 70 degree downward angle, with an extraparenchimal portion which is about 1 cm long in 50-60% of cases. In 90% of cases a common hepatic vein formed by the median hepatic vein and the left hepatic vein is present and it joins the IVC in an almost horizontal direction.

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