THE COMMOX ILIAC ARTERIES. 



619 



point in one case out of eight ; and below it in one ease out of six. The left common iliac 

 artery divides lower down more frequently than the right. 



The rilntir, /myth. also, of the two common iliac arteries varies. The right common iliac 

 was the lonirer in sixty-three cases, the left in fifty-two, whilst they were both equal in fifty- 

 three. The length of the arteries varied in five-sevenths of the cases examined from an inch 

 and a half to three inches : in about half of the remaining cases the artery was longer and in 

 the other half shorter, the minimum length being less than half an inch, the maximum four 

 and a half inches. In two instances the right common iliac has been found wanting, the 

 external and internal iliacs arising directly from the aorta. 



Surface Marking. Draw a zone round the body opposite the highest part of the crest 

 of the ilium : in this line take a point half an inch to the left of the middle line. From this 



Heo-lttmbar. 



Gluteal. 



FIG. 372. Arteries of the pelvis. 



draw two lines to points midway between the anterior superior spines of the ilium and the 

 symphysis pubis. These two diverging lines will represent the course of the common and 

 external iliac arteries. Draw a second zone round the body corresponding to the level of the 

 anterior superior spines of the ilium : the portion of the diverging lines between the two zones 

 will represent the course of the common iliac artery : the portion below the lower zone, that of 

 the external iliac artery. 



Surgical Anatomy. The application of a ligature to the common iliac artery may be 

 required on account of aneurism or haemorrhage implicating the external or internal iliacs. 

 The artery may be tied by one or two incisions : 1 . an anterior or iliac incision, by which the vessel 

 is approached more directly from the front : and 2. a posterior abdominal or lumbar incision, by 

 which the vessel is reached from behind. If the surgeon select the iliac region, a curved incis- 

 ion, from five to eight inches in length according to the amount of fat. is made, commencing just 

 outside the middle of Poupart's ligament and a finger's breadth above it. and carried outward 

 toward the anterior superior iliac spine, then upward toward the ribs, and finally curving inward 



