THE EXTERNAL ILIAC ARTERY. 819 



line from the common iliac to beneath Poupart's hgament, and in such cases it makes a more 

 or less pronounced bend which may dip below the brim of the pelvis. In the embryo it is a 

 comparatively small vessel, the main supply of the lower limb being through the sciatic, which 

 is continuous below with the popliteal (page S23). Occasionally this condition is retained, the 

 artery then terminating by becoming the deep instead of the common femoral. 



In addition to the usual branches it may give off the obturator (page 814), or an accessory 

 deep epigastric or deep circumflex iliac. Or branches usually arising from the common femoral, 

 such as the superficial e.xternal pudic or even the profunda femoris, may arise from it. 



Practical Considerations. — The external iliac artery is occasionally the seat 

 of aneurism, and such tumors have been mistaken for malignant growths or for 

 abscess. A swelling with expansile pulsation and bruit can usually be found in the 

 line of the vessel near the brim of the pelvis, and the patient will be unable to extend 

 freely the thigh or the trunk, and will lean forward in walking or standing to reheve 

 the ilio-psoas from pressure. There is apt to be pain in the groin and down the front 

 of the thigh from pressure on the anterior crural nerve, or on the crural branch 

 of the genito-crural. 



It may be imperfectly compressed just above its termination at the middle of 

 Poupart's ligament, but, as is the case with the common and internal iliacs, the 

 circulation through it is better controlled by pressure on the abdominal aorta. The 

 line of the vessel extends from a point half-way between the pubic symphysis and the 

 anterior superior spinous process to a point a litde below and to the left of the 

 umbilicus. The course of the external iliac corresponds to the lower third of this 

 line, the upper two-thirds representing the line of the common iliac. 



Ligation of the vessel has been done for aneurism of the common femoral, for 

 hemorrhage, and as a palliative in malignant growths or in elephantiasis of the 

 extremity. 



Like the other iliacs, it may be approached by either: (i) the intraperitoneal; 

 or (2) the extraperitoneal route. 



1. The incision should be made in the semilunar line, and will thus cross the 

 line of the vessel obliquely. Its lower end should reach Poupart's ligament. Its 

 length will vary (with the thickness of the abdominal wall) from three inches to four 

 inches. The superficial circumflex ilii qnd the deep epigastric arteries may require 

 ligation. The intestines are displaced upward. At the left side the sigmoid flexure, 

 and on the right the termination of the ileum, may be found in close relation to the 

 vessel. On both sides the spermatic vessels cross it, and their distention (analogous 

 to that of the mesenteric vessels spoken of in connection with ligation of the left 

 common iliac) (page 808), when deprived of their peritoneal support, has been noted 

 (Makins). 



The peritoneum over the vessel — on the left side possibly a part of the sigmoid 

 mesocolon — is divided parallel with the long axis of the artery, and the needle is 

 passed from the vein. 



2. Ligation by the extraperitoneal method — still preferred by many surgeons in 

 the case of this vessel — is done through an incision parallel with Poupart's ligament, 

 but slightly convex downward, beginning one inch above the anterior superior spinous 

 process of the ilium and ending at the outer pillar of the external abdominal ring. 

 After dividing the abdominal muscles and the transversalis fascia, the separation of 

 the peritoneum from the iliac fascia is begun near the outer extremity of the wound, 

 where the subperitoneal areolar tissue is more abundant and the connection .of the 

 peritoneum and the fascia less intimate. After the detachment has been effected 

 (chiefly by means of a finger), the vessel is exposed with the vein lying behind 

 it above and to the inner side near Poupart's ligament, and the anterior crural 

 nerve some distance to the outer side. The needle should be passed from within 

 outward. 



The collateral circulation is carried on from above the ligature oy (a) the lumbar; 

 (<5) the obturator; (c) the sciatic; (^) the gluteal; (<?) the internal pudic; and (/) 

 the internal mammary and lower intercostals anastomosing respectively with (a) the 

 deep circumflex iliac; {b) the internal circumflex; (c) the perforating (profunda); 

 id') the external circumflex; (^ ) the external pudic (femoral); and (/") the deep 

 epigastric from below. 



