Kidneys

• Location: 

  • Located  in the posterior abdomen, paravertebraly in the retro peritoneum

  • They are situated at the level of the costo-veretebral angle

  • The right kidney is 2-8 cm lower than the left Kidney, because of the large liver which sits superior to it.

• Shape: 

  • Bean shaped

  • Hilum

    • Hilus leads into the renal sinus which contains renal artery, vein and renal pelvis. 

      • Renal vein anteriorly, Renal artery in middle and  Renal pelvis posteriorly

• Size:

  • Measures 9-11 cm in length x 6 cm in Width x 3 cm in AP   

    • US is the best modality to obtain the size of kidneys

• Contour

  • Smooth

• Axis

  • Long axis - directed outwards and laterally

  • Tilted, superior pole closer to mid line

• Relationship: 

  • Anteriorly the right kidney is related to the Liver, duodenum and hepatic flexure of ascending colon

  • Anteriorly the left kidney is related to Stomach, Jejunum, Pancreas, Spleen and descending Colon

  • Adrenal gland is superior and anterior to the Kidneys

  • The kidney is surrounded by a distinct layer of fascia (Perirenal fascia) that separates the fat surrounding the kidney into the perinephric and paranephric fat. Kidneys lie in a fatty cushion of perinephric fat

  • Right Kidney is related to the 12th rib posteriorly resting on diaphragm

  • The left kidney rises to as high as the 11th thoracic rib posteriorly, extending  from T11-L3, resting on diaphragm

• Renal Structure: 

  • Thin capsule

  • Renal cortex

    • Renal cortex consists of glomeruli and renal tubules

    • Normal thickness is 2.5 cms

  • Medulla

    • Consists of multiple renal pyramids which have their base to the periphery and their conical end directed towards the renal hilus. 

    • Their tips are called papillae. 

    • Each minor calyx receives 1-3 papillae, through which the collecting tubules empty.

    • Columns

• Embryology: 

  • The kidneys develop in the pelvis and ascend up. 

  • If arrested, they can be seen in various portion of their route. 

  • They may fuse to form a horseshoe kidney.

Applied Anatomy