Genitourinary Radiology > Anatomy > Kidneys


Retroperitoneal against posterior abdominal wall at level of T12-L3 vertebrae, the right kidney slightly lower than the left due to displacement by the right lobe of liver. The right kidney is posterior to the liver, duodenum and ascending colon; the left kidney is related to the spleen, stomach, pancreas, jejunum, and descending colon.

There are many variations of the renal vasculature—the following is the most common configuration. The renal arteries branch from the abdominal aorta between L1 and L2, the right renal artery passing posterior to the IVC. There may be more than one renal artery (on one or both sides) in 20-30% of the time. The renal veins lie anterior to the arteries; the longer left renal vein passes anterior to the aorta before draining into the inferior vena cava. This anatomy makes the left kidney more desireable for transplant giving the surgeon some extra vessel to work with for creating the vascular anastomoses in the recipient. Common variants include retroaortic and circumaortic left renal veins.

Superior and inferior poles, anterior and posterior surfaces, medial and lateral margins. The renal hilum, located at the medial margin, is a cleft that provides access for the vasculature and an exit for the ureters. A tough, fibrous capsule surrounds the kidney.

The renal hilum opens up into the renal sinus, a space in which the renal pelvis, calices, vessels, and nerves lie surrounded by fat. The renal pelvis is the superior end of the ureter, formed from two to three major calices. Each major calyx is formed from two or three minor calices, into which protrude a renal papilla, the apex of pyramid-shaped clusters of collecting ducts that form the renal medulla. Surrounding the medulla is the renal cortex, the excretory system of the kidney that contains the Bowman’s capsule, the proximal and distal convoluted tubules, the loop of Henle, and supporting parenchymal tissue and vasculature. Each minor calyx with its associated pyramid and cortex comprises one lobule of the kidney, these lobules having formed from distinct embryologic structures (mesonephros) that coalesce during renal development.

Normal excretory phase of an IVU (intravenous urogram).  This film was taken approximately 10 minutes following IV injection of iodinated contrast material.  The kidneys are excreting contrast into non dilated calyces (arrows), renal pelvis (p), ureters (*) and bladder (B).

Contrast enhanced CT scan through the kidneys in nephrogram phase (showing corticomedullary differentiation).  This is approximately 100 seconds following contrast administration and would show renal lesions well.

Contrast enhanced CT scan through the kidneys in pyelogram phase (showing excretion of contrast into the collecting system).  This is approximately 8 minutes following contrast administration and would show urothelial lesions well, such as transitional cell carcinoma, stones, blood clots.

Renal Ultrasound. Sagittal view of normal left kidney showing normal cortex (C) and echogenic (bright) renal sinus fat (F).

Color Doppler Renal Ultrasound. View of normal right renal artery (red) and vein (blue) with spectral analysis (bottom of image) showing normal low resisitence wave form in the artery.

T2 weighted images through the kidneys (K) in the coronal plane.

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