Formed at L5 by the common iliac veins, receiving lumbar, gonadal, renal, adrenal, phrenic and hepatic veins
Mnemonic
“I Like To Rise So High”, from below upwards:
- I - Iliac veins, common, which form it at L5
- L - Lumbar veins
- T - Testicular or ovarian, right only
- R - Renal veins
- S - Suprarenal, right only
- H - Hepatic veins, and the inferior phrenic
It pierces the diaphragm at T8 and enters the right atrium.
The left gonadal and left suprarenal veins drain into the left renal vein, not the cava, which is why a left varicocele is commoner and why a new one raises the possibility of a left renal tumour obstructing that vein.
The IVC is on the right and the aorta on the left, so the right renal artery passes behind the cava and the left renal vein passes in front of the aorta, under the superior mesenteric artery, where it can be compressed in the nutcracker syndrome.
Expansion
- Formed at L5 by the union of the two common iliac veins, to the right of the midline
- Leaves through the caval opening of the diaphragm at T8
Tributaries, ascending:
- Lumbar veins
- Right gonadal vein (the left drains into the left renal vein)
- Renal veins
- Right adrenal vein (the left drains into the left renal vein)
- Right inferior phrenic vein
- Hepatic veins - the last tributaries, just below the diaphragm
The asymmetry is the point worth memorising: left gonadal and left adrenal veins take the indirect route through the left renal vein, while their right counterparts join the cava directly.
The inferior vena cava also lies posterior to the epiploic foramen, the duodenum and the head of the pancreas, so it can be involved by tumours of those structures.