Liver, duodenum and colon in front of the right; stomach, pancreas, spleen and colon in front of the left
Mnemonic
“The right is lower, the left is higher”, because the liver displaces the right kidney:
- Right kidney - T12 to L3
- Left kidney - T11 to L2
Posterior relations are the same for both and explain the loin approach: diaphragm, psoas, quadratus lumborum, transversus abdominis, and the subcostal, iliohypogastric and ilioinguinal nerves, with the 12th rib crossing behind, and the pleura reaching down to it.
“The pleura reaches the 12th rib”, which is why a posterior nephrectomy or a percutaneous nephrostomy risks a pneumothorax.
Anterior relations differ: the right is related to the liver, duodenum and hepatic flexure; the left to the stomach, spleen, pancreas, splenic flexure and jejunum.
Hilar structures run “vein, artery, ureter” from front to back, remembered as VAU, 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
Right kidney, anterior relations
- Right lobe of the liver
- Second part of the duodenum, over the hilum
- Hepatic flexure of the colon
- Right adrenal gland, at the upper pole
Left kidney, anterior relations
- Stomach and spleen
- Pancreas (body and tail)
- Splenic flexure and descending colon
- Jejunum
- Left adrenal gland
Posteriorly, both rest on the diaphragm, psoas major, quadratus lumborum and transversus abdominis, with the twelfth rib crossing behind.
These relations explain the injuries seen in renal surgery and trauma: duodenal injury on the right, and pancreatic tail or splenic injury on the left. They also explain why a renal mass can present with gastrointestinal symptoms.