430 ARTERIES. 



of secondary hemorrhage after amputation of the thigh high up. It has been seen, that the 

 origin of this vessel corresponds to the left side of the umbilicus on a level with a line drawn 

 from the highest point of one iliac crest to the opposite one. and its course to a line extending 

 from the left side of the umbilicus downwards towards the middle of Poupart's ligament. The 

 line of incision required in the first steps of an operation for securing this vessel, would materially 

 depend upon the nature of the disease. If the surgeon select the iliac region, a curved incision, 

 about five inches in length, may be made, commencing on the left side of the umbilicus, carried 

 outwards towards the anterior superior iliac spine, and then along the upper border of Poupart's 

 ligament, as far as its middle. But if the aneurismal tumor should extend high up in the abdo- 

 men, along the external iliac, it is better to select the side of the abdomen, approaching the artery 

 from above, by making an incision from four to five inches in length, from about two inches above 

 and to the left of the umbilicus, carried outwards in a curved direction towards the lumbar region, 

 and terminating a little below the anterior superior iliac spine. The abdominal muscles (in either 

 case) having been cautiously divided in succession, the transversalis fascia must be carefully cut 

 through, and the peritoneum, together with the ureter, separated from the artery, and pushed 

 aside : the sacro-iliac articulation must then be felt for, and upon it the vessel will be felt pulsat- 

 ing, and may be fully exposed in close connection with its accompanying vein. On the right 

 side, both common iliac veins, as well as the inferior vena cava, are in close connection with the 

 artery, and must be carefully avoided. On the left side, the vein usually lies on the inner side, 

 and behind the artery ; but it occasionally happens, that the two common iliac veins are joined 

 on the left instead of the right side, which would add much to the difficulty of an operation in 

 such a case. If the common iliac artery is so short that danger is to be apprehended from 

 secondary hemorrhage if a ligature is applied to it, it would be preferable, in such a case, to tie 

 both the external and internal iliacs near their origin. This operation has been performed in 17 

 cases, 9 of which were cured, and 8 died. 



Collateral Circulation. The principal agents in carrying on the collateral circulation after 

 the application of a ligature to the common iliac, are, the anastomoses of the hemorrhoidal 

 branches of the internal iliac with the superior hemorrhoidal from the inferior mesenteric ; and 

 by the anastomoses of the uterine and ovarian arteries, and of the vesical arteries of opposite 

 sides; of the lateral sacral with the middle sacral artery; of the epigastric with the internal 

 mammary, inferior intercostal and lumbar arteries ; of the ilio-lumbar with the last lumbar artery ; 

 of the obturator artery, by means of its pubic branch, with the vessel of the opposite side, and 

 with the internal epigastric ; and of the gluteal with the posterior branches of the sacral arteries. 



INTERNAL ILIAC ARTERY. 



The Internal Iliac Artery supplies the walls and viscera of the pelvis, the gene- 

 rative organs, and inner side of the thigh. It is a short, thick vessel, smaller than 

 the external iliac, and about an inch and a-half in length, which arises at the point 

 of bifurcation of the common iliac ; and, passing downwards to the upper margin 

 of the great sacro-sciatic foramen, divides into two large trunks, an anterior and 

 posterior ; a partially obliterated cord, the hypogastric artery, extending from the 

 extremity of the vessel forwards to the bladder. 



Relations. In front, with the ureter, which separates it from the peritoneum. 

 Behind, with the internal iliac vein, the lumbo-sacral nerve, and Pyriformis 

 muscle. By its outer side, near its origin, with the Psoas magnus muscle. 



PLAN OF THE EELATIONS OF THE INTERNAL ILIAC ARTERY. 



In front. 

 Peritoneum. 

 Ureter. 



Outer side. 

 Psoas magnus. 



Behind. 



Internal iliac vein. 

 Lumbo-sacral nerve. 

 Pyriformis muscle. 



In the foetus, the internal iliac artery (hypogastric) is twice as large as the 

 external iliac, and appears the continuation of the common iliac. Passing forwards 



