Spleen

• Spleen


  A haemo-lymph organ that belongs to the reticulo-endothelial system

  
• Spleen


  • 2nd lymphoid organ
  • Pleural cavity separates it from the diaphragm and ribs
• Functions of the spleen

  • Forms part of the reticuloendothelial system
  • Hematopoiesis in fetal life and reutilization of iron from hemoglobin of destroyed red blood cells in adults
  • Contains red and white pulp separated by the marginal sinus
  • Red pulp filters red blood cells and reserves monocytes
  • White pulp helps in active immune response

  
• Development of the spleen

  1. Develops from mesenchymal cells in the dorsal mesogastrium during the 5th week of gestation

  2. Number of nodules develop which soon fuse to form a lobulated spleen

  3. Notching of superior border is evidence of multiple origin

  4. Unfused nodules form accessory spleens

  
• Locations of accessory spleens

  • Derivatives of dorsal mesogastrium
  • Broad ligament of uterus
  • Spermatic cord

  
• Position of the spleen

  • Lies between fundus of stomach and diaphragm
  • In left hypochondrium and epigastrium
  • Extends from 9th to 11th ribs
  • Axis directed downwards, forwards and laterally along the 10th rib

  
• Measurements of the spleen

  • Length - 12 cm
  • Breadth - 7 cm
  • Thickness - 3 cm
  • Weight - 150 g

  
• Harris' dictum of odd numbers on the spleen: 1, 3, 5, 7, 9, 11

  
• Peritoneal covering of the spleen


  Covers the spleen except at the hilum

  
• External features of the spleen

  • Two ends
  • Three borders
  • Two surfaces
  • Two angles
  • Hilum

  
• Anterior/lateral end of the spleen

  Expanded, directed downwards and forwards to mid-axillary line

  
• Posterior/medial end of the spleen

  Rounded, directed upwards, backwards and medially, resting on upper pole of left kidney

  
• Superior border of the spleen


  Presents one or two notches near anterior end, indicating lobulated development

  
• Surfaces of the spleen

  • Diaphragmatic surface - convex and smooth, related to diaphragm, left lung, pleura, costodiaphragmatic recess, 9th-11th ribs
  • Visceral surface - concave and irregular, related to fundus of stomach, anterior surface of left kidney, splenic flexure of colon, tail of pancreas