Renal vein

Anatomy and course

In the kidney, the blood drainage starts with the peritubular plexuses that give off fine venules that form the interlobular veins. The interlobular veins anastomose with each other and drain into the arcuate veins. Further, the arcuate veins drain into the interlobar veins that merge to form a single renal vein.

The right renal vein is a short vein (about 2-3 cm long) that runs anterior to its corresponding artery. It courses retroperitoneally, passing posterior to the descending segment of the duodenum. It terminates by draining into the inferior vena cava at a right angle.

The left renal vein is more than three times longer than its right counterpart (about 7 cm). It courses posterior to the splenic vein and pancreas. Then, the vein crosses the aorta anteriorly, immediately below the origin of the superior mesenteric artery (mesoaortic angle). This is a clinically significant relation since this is a common point of renal vein compression (nutcracker syndrome). Due to its relatively long course across the abdomen, the left vein receives several tributaries from other organs including the left ovary/testicle, left suprarenal gland and left portion of the diaphragm. The tributaries of the left vein include:

• left gonadal vein
• left inferior phrenic vein
• left adrenal vein
• capsular veins of the left kidney

Similar to the right, the left vein is accompanied by its corresponding artery and empties into the inferior vena cava. Occasionally, there can be two left renal veins present. When this happens, one runs anterior and the other posterior to the aorta forming the ‘renal collar’. The vein that runs posterior to the aorta is also referred to as the circumaortic left renal vein.