Some structures contact the kidneys directly, while others are separated from them by the peritoneum.

The anterior surface of the right kidney is related to several structures:

• Right suprarenal gland (adrenal gland) - covers a small part of the superior pole of the right kidney;
• Liver - connected with a large part of the rest of the superior portion of the right kidney, separated by a layer of peritoneum;
• Descending part of the duodenum - lies retroperitoneally and contacts the right kidney medially;
• Right colic flexure - directly contacts the inferior pole of the right kidney, on the lateral side;
• Segment of the intraperitoneal small intestine - contacts the inferior pole on its medial side.
   

The anterior surface of the left kidney also is related to several structures, including:

• Left suprarenal gland (adrenal gland) - covers a small part of the superior pole, on its medial side;
• Stomach (removed for better visualisation of other organs) and spleen - intraperitoneal organs contacting the rest of the anterior aspect of the superior pole of the left kidney;
• Pancreas - retroperitoneal organ that covers the middle part of the left kidney;
• Left colic flexure and the beginning of the descending colon - contacts the lower half of the left kidney on its lateral side;
• Parts of the intraperitoneal jejunum - covers the inferior pole of the left kidney on the medial side.

Posteriorly, the right and left kidneys are related to similar structures on both sides: superiorly, they contact the diaphragm (removed), and inferiorly they are connected with the following muscles (from medial to lateral side): psoas major, quadratus lumborum, and transversus abdominis.

The superior pole of the right kidney is located anterior to the 12th rib, while the superior pole of the left kidney is anterior to the 11th and 12th ribs.

The pleural sacs and, specifically, the costodiaphragmatic recesses extend posterior to the kidneys. Also posterior to the kidneys, the subcostal blood vessels pass, as well as the iliohypogastric and ilioinguinal nerves.