20.Kidney

• Kidneys


  • Level of T12 - L3
  • Closely in contact with Psoas major
• Coverings of the kidneys

  • Perirenal fat
  • Renal fascia / Gerota
  • Pararenal fat
• Structures that enter/leave at renal hilum

  • Renal vein - anterior
  • Renal artery
  • Renal pelvis - posterior
• Right Kidney


  • Anterior structures: Suprarenal gland, Liver, Duodenum 2nd part, Right colic flexure
  • Posterior structures: Diaphragm, 12th rib, costodiapragmatic recess of the pleura, psoas muscle, quadratus lumborum muscle, transversus abdominis muscle, subcostal (T12) nerve, iliohypogastric nerve, ilioinguinal nerve
• Left Kidney


  • Anterior structures: Suprarenal gland, Spleen, Pancreas, Stomach, Left colic flexure, Jejunum
  • Posterior structures: Diaphragm, 11th and 12th ribs, costodiaphragmatic recess of the pleura; psoas, quadratus lumborum and transversus abdominis muscles; subcostal (T12), iliohypogastric and ilioinguinal nerves
• Kidneys


  • Retroperitoneal location
• Left Kidney


  • Hilum at level L1
  • Related to ribs 11 and 12 posteriorly
  • Normal weight - 150 gms on the average
• Right Kidney


  • Hilum at level between L1 and L2
  • Related to rib 12 posteriorly
  • Normal weight - 140 gms on the average
• Fibrous capsule


  True capsule
• Perirenal fat


  Fat covering fibrous capsule
• Renal Fascia


  "Gerotas fascia"; Areolar tissue outside of perirenal fat. Encloses kidney and suprarenal glands; continuous laterally with the fascia transversalis
• Pararenal fat


  External to renal fascia; forms part of the retroperitoneal fat
• Outer cortex


  • Forms the outer part of the kidney and projects into the medullary region between the renal pyramids as Renal Columns
  • Contains RENAL CORPUSCLES (Glomerulus surrounded by Bowman's capsule), PCT and DCT
  • Extends into medulla between adjacent pyramids (Renal columns)
• Inner medulla


  • Forms the inner part, consists of 8 to 12 RENAL PYRAMIDS (Malpighi) which contain straight tubules (Henle's loops) and Collecting tubules
  • Apex of the Renal pyramid called as Renal Papilla fits into the Minor Calyx on which the collecting tubules open
  • 12 renal pyramids (base toward cortex; apex – renal papilla oriented medially)
• Medullary rays


  Striations from bases of pyramids to cortex
• Renal Pelvis


  • Upper expanded end of ureter
  • Divided into 2 or 3 major calyces
  • Subsequently divided into 2 or 3 minor calyces
  • Each minor calyx indented by apex of renal pyramid (renal papilla)
• Renal artery


  From aorta at level L2
• Renal vein


  To IVC
• Lymph drainage


  Lateral aortic lymph nodes
• Nerve supply


  • Renal sympathetic plexus
  • Afferent fibers enter the SC in the 10th, 11th and 12th thoracic vertebras
• Renal artery


  1. Segmental arteries

  2. Interlobar arteries that communicate with one another via arcuate arteries

  3. Arcuate arteries give off branches called interlobular arteries that extend into the cortex
• Venous return


  Via similarly named veins
• PREAORTIC lymph nodes


  • Referred to as Celiac, Superior mesenteric and Inferior mesenteric lymph nodes
• Lateral aortic / Para-aortic / Lumbar lymph nodes

  • Located on the Posterior abdominal wall - kidneys, suprarenal
• Arterial Supply to the Kidney

  Abdominal aorta → renal artery → segmental artery → interlobar arteries → arcuate arteries → interlobular arteries
• Venous Drainage from the Kidney


  Vasa recta → interlobular veins → arcuate veins → interlobar veins → renal vein → IVC
• Renal transplantation


  • Iliac fossa on the posterior abdominal wall is the usual site
  • Incision in the anterior abdominal wall just above the inguinal ligament; iliac fossa in front of iliacus muscle is approached retroperitoneally
• Renal transplantation procedure


  1. Renal artery is anastomosed to the Internal iliac artery

  2. Renal vein to External Iliac vein

  3. Ureterocystostomy is performed
• Right renal artery


  • Longer
  • Passes posterior to the IVC
• Left renal artery


  • Courses posterior to left renal vein
• Left renal vein


  • Longer
  • Passes in between superior mesenteric artery and abdominal aorta