Kidney Anatomy| Relation-kidney| Boundaries- kidney| Blood supply

ANATOMY OF KIDNEY

ANATOMY OF KIDNEY;

The kidneys are large, reddish bean shaped structures present at vertebral level T12-L3 vertebra in retroperitoneal space of abdominal cavity. Superior part of kidney lies deep to 11th and 12th ribs. Inferior pole of right kidney lies one finger breadth superior to iliac crest. Each kidney move 2-3 cm in vertical direction during respiration. It is Measure about 10*5*2.5 in length breadth and width respectively. On the upper pole of each kidney, embedded within the renal fascia and a thick protective layer of peritoneal adipose tissue, lies an adrenal gland. The medial border is concave and has a deep fissure called the hilum. A section through the kidney shows relationship of different structures that lie within the hilum in a space called renal sinus.

Relation of kidney 

• Postero-superiorly:-diaphragm
• Postero-inferiorly:-psoas major and quadratus lumborum muscle
• Anteriorly(right kidney):-liver, duodenum and ascending colon
• Anterior(left kidney):-stomach, spleen, pancreas, jejunum and descending colon

Note:-subcostal nerve and vessel, iliohypogastric and ilioinguinal nerves descend diagonally across posterior border of kidney.

Boundaries of  kidney

 

• Two poles i.e. superior pole and inferior pole
• Two surfaces i.e. anterior and posterior
• Two margins i.e. medial and lateral
• Lateral margin of kidneys is convex while medial margin is concave. The concave medial margin contains renal sinus and renal pelvis.

Blood supply

• Kidney is supplied by renal arteries which at renal hilum divides into segmental arteries which are end arteries.
• The branches are apical, antero-superior, antero-inferior, inferior and posterior segmental arteries.
• kidney is drained by renal veins and its formation are variable.

Nerves Supply

• Innervated by renal nerve plexus formed by fibers from abdominopelvic plexus.

Lymphatic drainage

• Renal lymphatic vessels follow renal vein and drains into the right and left lumbar(caval and aortic) lymph nodes.

Histology of kidney

Cut section of kidney shows it has 2 part

• Outer:-Cortex
• Inner:-Medulla

Cortex

• It is covered by capsule, thin layer of connective tissue, which consists of two distinct
  layers, outer fibroblasts and collagen fiber and inner layer of with cellular
  components of myofibroblasts.
• Tissue lying between the bases of the pyramids(triangular areas of renal tissue) and the surface of the kidney, forming the cortical arches or cortical lobules. This part of the cortex shows light and dark striations. The light lines are called medullary rays.

Medulla

• The renal medulla appears striped, as it contains vertical nephron structures (tubules, collecting ducts).
• It consists of renal (medullary) pyramids separated by projections of the renal cortex (renal columns). 
• The apices of the pyramids project towards the renal pelvis and open into the minor calyces via perforated plates on their surfaces (area cribrosa). 
• Each renal pyramid, with its surrounding cortical tissue, forms a renal lobe. Renal lobes are further divided into renal lobules.

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