THE EXTERNAL ILIAC ARTERY 681 



major, distributing branches to the Gluteus muscles, and anastomoses with the 

 external circumflex artery. Some branches pierce the Gluteus minimus to supply 

 the hip-joint. 



Surface Marking. The position of the three main branches of the internal iliac, the 

 sciatic, internal pudic, and gluteal, which may occasionally be the object of surgical interference, 

 is indicated on the surface in the following way: A line is to be drawn from the posterior supe- 

 rior iliac spine to the posterior superior angle of the great trochanter, with the limb slightly 

 flexed and rotated inward; the point of emergence of the gluteal artery from the upper part of 

 the sciatic notch will correspond with the junction of the upper with the middle third of this 

 line. A second line is to be drawn from the same point to the outer part of the tuberosity of 

 the ischium; the junction of the lower with the middle third marks the point of emergence of 

 the sciatic and pudic arteries from the great sciatic notch. 



Applied Anatomy. Any of these three vessels may require ligating for a wound or for 

 aneurism, which is generally traumatic. The gluteal artery is ligated by turning the patient 

 two-thirds oyer on his face and making an incision from thp-pQsteElQE-sifflfirJQr spi'np of the ilium 

 to the upper and posterior angle of the great trochanter. This must expose the Gluteus maxi- 

 mus muscle, and its fibres are to he separated through the whole thickness of the muscle and 

 pulled apart with retractors. The contiguous margins of the Gluteus medius and Pyriformis 

 are now to be separated from each other, and the artery will be exposed emerging from the 

 sciatic notch. In ligation of the sciatic artery, the incision should be made parallel with that 

 for ligation of the gluteal, but one inch and a half lower down. After the fibres of the Gluteus 

 maximus haye been separated, the yessel is to be sought for at the lower border of the Pyri- 

 formis; the preat sciatic nerve, which lies just above it, forms the chief guide to the artery. 

 The internal pudic can be reached through the incision used to reach the sciatic. 



The External Iliac Artery (A. Iliaca Externa) (Fig. 473). 



The external iliac artery is larger in the adult than is the internal iliac. It 

 passes obliquely downward and outward along the inner border of the Psoas 

 muscle, from the bifurcation of the common iliac to a point beneath Poupart's 

 ligament, midway between the anterior superior spine of the ilium and the sym- 

 physis pubis, where it enters the thigh and becomes the femoral artery. 



Relations. In front, the artery is in relation with the peritoneum, subperitoneal areolar 

 tissue, the termination of the ileum on the right side, and the sigmoid flexure on the left, and a 

 thin layer of fascia derived from the iliac fascia, which surrounds the artery and vein. At its 

 origin it is crossed by the ovarian artery in the female, and occasionally by the ureter. The 

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

 this situation by the genital branch of the genitofemoral nerve and the deep circumflex iliac 

 vein; the vas deferens in the male, and the round ligament in the female, curve down along its 

 inner side. Behind, it is in relation with the inner border of the Psoas muscle, from which it is 

 separated by the iliac fascia. At the upper part of its course, the external iliac vein lies partly 

 behind it, but lower down lies entirely to its inner side. Externally, it rests against the Psoas 

 muscle, from which it is separated by the iliac fascia. Numerous lymphatic vessels and nodes 

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



PLAN OF THE RELATIONS OF THE EXTERNAL ILIAC ARTERY. 



In front. 



Peritoneum, intestines, and fascia. 

 Near ( Lymphatic vessels and nodes. 

 Pouna t' < Spermatic vessels. 

 Ligament ) Genitofemoral nerve (genital branch). 

 v. Deep circumflex iliac vein. 



Outer side. / \ Inner side. 



Psoas magnus. iiiac. a External iliac vein and vas deferens 



Iliac fascia. / near Poupart's ligament. 



V ^/ 



Behind. 



External iliac vein. 

 Psoas magnus. 



