254 Anatomy Applied to Medicine and Swgery. 



H fsmorrhagic infarction of the spleen is due 

 to a plugging of one of the branches of the splenic artery 

 by an embolus. These branches are terminal, i.e., they -do 

 not anastomose with one another, but end in the splenic 

 pulp there being no capillaries in the spleen and from 

 this pulp, the radicles of the splenic vein arise. An em- 

 bolus being carried to the spleen and lodging in one of the 

 arterioles, shuts off the circulation from the area sup- 

 plied by that vessel with the production of a wedge- 

 shaped infarction. The connection of the venous radicle 

 with the other end of the anaemic area allows a back flow 

 of blood from the valveless splenic vein, thus forming 

 what is known as a "hsemorrhagic infarction." The 

 base of the wedge-shaped infarction does not quite touch 

 the surface of the spleen, since there is a very thin layer of 

 healthy tissue overlying it beneath the capsule. This area 

 of healthy tissue is nourished by small twigs from sources 

 other than the intra-splenic vessels, viz., from the supra- 

 renal, the phrenic, etc., and is, therefore, not affected by the 

 infarction. Movable or wandering spleen may be a part 

 of the general condition of prolapse of the viscera vis- 

 ceroptosis, or it may be due to a local relaxation or 

 lengthening of the ligaments sustaining the spleen, espe- 

 cially the phreno-colic and the suspensory ligaments. 

 When movable, the organ becomes more or less enlarged, 

 and may present symptoms of dragging, or of uneasy sen- 

 sations in the left hypochondriac region, or there may re- 

 sult the more severe and generally fatal train of shock, 

 fever and gangrene from a twisting or torsion of the ped- 

 icle which contains the splenic vessels and nerves. 



Congestion of the Spleen. In health there is always 

 more or less congestion of the spleen during or at the com- 

 pletion of the act of digestion, but, in disease, the organ 

 may be acutely congested in fevers, etc., or, chronically, 



