264 Anatomy Applied to Medicine and Surgery. 



would fall away from the bloodvessel and the pulsations 

 would cease, whereas, in the case of an aneurism, pulsa- 

 tion would still continue. The mobility of an aneurism 

 involving the superior or inferior mesenteric arteries, 

 will assist in distinguishing it from one affecting the 

 aorta itself. The superior mesenteric artery may be plug- 

 ged by an embolus a condition which generally ends 

 fatally. This vessel supplies the whole length of the small 

 intestine with the exception of the upper part of the duode- 

 num, which is supplied by the pancreatico-duodenalis supe- 

 rior. The superior mesenteric is, therefore, distributed to 

 the caecum, ascending and transverse portions of the colon, 

 and the small intestine, and is, to all intents, a "terminal" 

 artery, since the territory supplied by it is so great, and the 

 anastomosis, that takes place between it and the branches 

 of the hepatic, inferior mesenteric, lumbar, ilio-lumbar, 

 etc., is so insignificant, that, when an embolus does 

 lodge in the vessel, it shuts off the circulation from nearly 

 the whole of the intestines, with the result that, among 

 other symptoms, there is intense pain. This pain, like 

 that of intestinal obstruction, is referred to the region of 

 the umbilicus. Static or moist gangrene may take place 

 in the territory from which the arterial blood supply is 

 shut off by the embolus. This is dependent on the back- 

 flow from the veins. When an embolus lodges in the 

 inferior mesenteric vessel, conditions similar to the above 

 may result. 



Ligation of the abdominal aorta. The aorta may 

 be ligated from in front by means of a median incision, 

 half above, and half below the umbilicus, or, it may be 

 approached from behind, through a curved incision reach- 

 ing from the tenth rib to a point one inch internal to the 

 anterior iliac spine. When the latter incision is em- 

 ployed, the abdominal muscles and the transversalis fascia 



