SPLEEX. 751 



for the entrance and exit of vessels and nerves. At the margins of the hilum, 

 the two layers of peritoneum are reflected from the surface of the spleen on to 

 the cardiac end of the stomach, forming the gastro-splenic omentum, which con- 

 tains between its layers the splenic vessels and nerves, and the vasa brevia. 

 The internal surface is in relation, in front, with the great end of the stomach ; 

 below, with the tail of the pancreas ; and behind, with the left crus of the Dia- 

 phragm and corresponding suprarenal capsule. The upper end, thick and 

 rounded, is in relation with the Diaphragm, to which it is connected by a fold 

 of peritoneum, the suspensory ligament. The lower end is pointed ; it is in re- 

 lation with the left extremity of the transverse arch of the colon. The anterior 

 margin is free, rounded, and often notched, especially below. The posterior 

 margin is rounded, and lies in relation with the left kidney, to which it is con- 

 nected by loose areolar tissue. 



The spleen is held in its position by two folds of peritoneum ; one, the gastro- 

 splenic omentum, connects it with the stomach ; and the other, the suspensory liga- 

 ment, with the under surface of the Diaphragm. 



Fig. 414. Transverse Section of the Spleen, showing the Trabecular Tissue and the Splenic 



Vein and its Branches. 



The size and weight of the spleen are liable to very extreme variations at 

 different periods of life, in different individuals, and in the same individual 

 under different conditions. In the adult, in whom it attains its greatest size, it 

 is usually about five inches in length, three or four inches in breadth, and an 

 inch or an inch and a half in thickness, and weighs about seven ounces. At 

 birth, its weight, in proportion to the entire body, is almost equal to what is 

 observed in the adult, being as 1 to 350 ; whilst in the adult it varies from 1 to 

 320 and 400. In old age, the organ not only decreases in weight, but decreases 

 considerably in proportion to the entire body, being as 1 to 700. The size of 

 the spleen is increased during and after digestion, and varies considerably, 

 according to the state of nutrition of the body, being large in highly-fed, and 

 small in starved animals. In intermittent and other fevers, it becomes much 

 enlarged, weighing occasionally from 18 to 20 pounds. 



Structure. The spleen is invested by two coats ; an external serous, and an 

 internal fibrous elastic coat. 



The external, or serous coat, is derived from the peritoneum ; it is thin, smooth, 

 and in the human subject intimately adherent to the fibrous elastic coat. It 

 invests almost the entire organ ; being reflected from it, at the hilum, on to the 



