The Kidneys

• Lumbar regions, in the superior of paravertebral gutters.
  
  
• From T12 – L3. The right kidney being a little lower (due to liver)
  
  
• Lie against psoas major muscle.
  
  
• Superior poles are protected by 11 th and 12 th ribs.
  
  
• The hila lie along the transpyloric plane.

The posterior relations are common

Muscles:

• psoas major
• Transversus abdominis
• quadratus lumborum
• diaphragm

Nerves

• subcostal nerve
• iliohypogastric nerve
• ilioinguinal nerve

Vessels:

• subcostal

Anterior relations vary from left to right

On the left

• left suprarenal
• stomach
• spleen
• pancreas
• jejunum
• descenbding colon

On the right

• liver (from which it is separated by the hepatorenal recess).
• right supra renal
• duodenum
• right colic flexure
• small intestine

• Fibrous renal capsule
  
  
• Perirenal fat (fatty renal capsule) – relatively less anteriorly.
  
  
• Fibro areolar tissue called renal fascia. This also encloses the suprarenal
  
  
• Pararenal fat – outside the renal fascia.
  
• The fat supports the kidney, but allows considerable mobility

Arterial supply

The renal arteries, branches of the aorta.

Note that the kidney develops in the pelvis, and “ascends” to lumbar region. The original blood supply is in the pelvis, the caudal vessels degenerates as it acquires vessels from the higher regions. This is the basis for some “polar” vessels which may originate from the:

• Internal iliac:
  
  
• Common iliac
  
  

These polar vessels are important as they must be ligated and cut during nephrectomy, and if they are damaged, may cause infarction of the area they supply.

Note: the artery may divide before the hilum and there may be multiple renal arteries.

Venous Drainage

• The renal veins carry the venous blood.
• The left renal vein is longer since the IVC is more to the right.
• It frequently receives the left gonadal vein.
• The left renal vein may also anastomose with the splenic vein (porto-systemic anastomosis).

• Lateral aortic nodes.

• From the renal plexus – lesser and lowest splanchnic and the vagus.