THE SPLEEN 



1307 



organ in the body. Not only does the size differ in different individuals but it 

 changes greatly with the blood content in the same individual. There is a dis- 

 tinct expansion for a time after each meal and the spleen contracts and expands 

 rythmicall}'. 



Fig. 1062. — Wedge-shaped Spleen, Visceral Surface. 



Diaphragmatic surface Margo anterior 



f 



Extremitas superior 



Margo posterior 



Splenic art. 

 Splenic vein 



Margo posterior 



Lower end of renal surface 



Gastric surface 



Hilus lienis 



Extremitas inferior 



In the adult it usually measures 10 to 15 cm. in length, 7.5 to 10 cm. in breadth, and 2.5 to 

 4 cm. in thickness. The weight usually ranges from 150 to 225 gm. At birth it represerits 

 from 3+0" to 400 of the total body weight and this porportion is maintained without much varia- 

 tion until the age of fifty years, when (like the Ij'mphoid organs in general) it begins to diminish 



Fig. 1063. — Tetrahedral-shaped Spleen, Visceral Surface. 



Extremitas superior 



Renal surface 

 Margo posterior 



Splenic art. 

 Splenic vein 



Intermediate angle 



Posterior extremity 



Gastric surface 



Hilus lienis 

 Margo anterior 



Anterior extremity 



Basal or colic surface 



in size. This diminution continues imtil in the very old it represents but yj y, of^the body weight- 

 There is no great difference in relative size in the two sexes. 



The spleen is somewhat soft and very friable. It is elastic, extensible, contractile, and 

 extremely vascular. 



Shape. — In form the spleen varies greatly. This is due largely to its softness 

 which permits considerable modifications by the pressure of the distended or con- 



