EXTERNAL ILIAC. 431 



femoral artery. The course of this vessel would be indicated by a line drawn 

 from the left side of the umbilicus to a point midway between the anterior supe- 

 rior spinous process of the ilium and the symphysis pubis. 



Relations. In front, with the peritoneum, sub-peritoneal areolar tissue, the 

 intestines, and a thin layer of fascia, derived from the iliac fascia, which surrounds 

 the artery and vein. At its origin it is occasionally crossed by the ureter. The 

 spermatic vessels descend for some distance upon it near its termination, and it is 

 crossed in this situation by a branch of the genito-crural nerve and the circumflex 

 iliac vein ; the vas deferens curves down along its inner side. Behind, it is in rela- 

 tion with the external iliac vein, which, at the femoral arch, lies at its inner side ; 

 on the left side the vein is altogether internal to the artery. Externally, it rests 

 against the Psoas muscle, from which it is separated by the iliac fascia. The 

 artery rests upon this muscle near Poupart's ligament. Numerous lymphatic 

 vessels and glands are found lying on the front and inner side of the vessel. 



PLAN OF THE KELATIONS OF THE EXTERNAL ARTERY. 



In front. 



Peritoneum, intestines, and iliac fascia. 

 Near f Spermatic vessels. 

 Poupart's ) Genito-crural nerve. 

 Ligament. 1 Circumflex iliac vein. 



[ Lymphatic vessels and glands. 



Outer side. / \ Inner side. 



Psoas magnus. [ External | External iliac vein and vas deferens 



Iliac fascia. I Ihac - / at femoral arch. 



Behind. 

 External iliac vein. 



Surgical Anatomy. The application of a ligature to the external iliac maybe required in 

 cases of aneurism of the femoral artery, or in cases of secondary hemorrhage, after the latter 

 vessel has been tied for popliteal aneurism. This vessel may be secured in any part of its course, 

 excepting near its upper end, on account of the circulation through the internal iliac, and near 

 its lower end, on account of the origin of the epigastric and circumflex iliac vessels. One of 

 the chief points in the performance of the operation is to secure the vessel without injury to the 

 peritoneum. The patient having been placed in the recumbent position, an incision should be 

 made, commencing about an inch above and to the inner side of the anterior superior spinous 

 process of the ilium, and running downwards and outwards to the outer end of Poupart's liga- 

 ment, and parallel with its outer half, to a little above its middle. The abdominal muscles and 

 transversalis fascia having been cautiously divided, the peritoneum should be separated from the 

 iliac fossa and pushed towards the pelvis ; and on introducing the finger to the bottom of the 

 wound the artery may be felt pulsating along the inner border of the Psoas muscle. The external 

 iliac vein is situated along the inner side of the artery, and must be cautiously separated from it 

 by the finger-nail, or handle of the knife, and the aneurism needle should be introduced on the 

 inner side, between the artery and vein. 



Collateral Circulation. The principal anastomoses in carrying on the collateral circulation, 

 after the application of a ligature to the external iliac, are, the ilio-lumbar with the circumflex 

 iliac ; the gluteal with the external circumflex ; the obturator with the internal circumflex ; the 

 sciatic with the profunda artery; the internal pudic with the external pudic, and with the internal 

 circumflex. When the obturator arises from the epigastric, it is supplied with blood by branches, 

 either from the internal iliac, the lateral sacral, or from the internal pudic. The epigastric 

 receives its supply from the internal mammary and inferior intercostal arteries, and from the 

 internal iliac, by the anastomoses of its branches with the obturator. 



Branches. Besides several small branches to the Psoas muscle and the neigh- 

 boring lymphatic glands, the external iliac gives off two branches of considerable 

 size : 



Epigastric. Circumflex iliac. 



The epigastric artery arises from the external iliac, a few lines above Poupart's 

 ligament. It at first descends to reach this ligament, and then ascends obliquely 

 upwards and inwards between the peritoneum and transversalis fascia, to the 



