(NGIOLOGY 



The superior gluteal artery (a. glutcpa superior; gluteal artery) (Fig. 544) is the 

 largest branch of the hypogastric, and appears to be the continuation of the pos- 

 terior division of that vessel. It is a short artery which runs backward between 

 the lumbosacral trunk and the first sacral nerve, and, passing out of the pelvis 

 above the upper border of the Piriformis, immediately divides into a superficial 

 and a deep branch. Within the pelvis it gives off a few branches to the Iliacus, 

 Piriformis, and Obturator internus, and just previous to quitting that cavity, a 

 nutrient artery which enters the ilium. 



The superficial branch enters the deep surface of the Glutteus maximus, and 

 divides into numerous branches, some of which supply the muscle and anastomose 

 with the inferior gluteal, while others perforate its tendinous origin, and supply 

 the integument covering the posterior surface of the sacrum, anastomosing with 

 the posterior branches of the lateral sacral arteries. 



The deep branch lies under the Glutseus medius and almost immediately sub- 

 divides into two. Of these, the superior division, continuing the original course 

 of the vessel, passes along the upper border of the Glutaeus minimus to the anterior 

 superior spine of the ilium, anastomosing with the deep iliac circumflex artery and 

 the ascending branch of the lateral femoral circumflex artery. The inferior division 

 crosses the Glutseus minimus obliquely to the greater trochanter, distributing 

 branches to the Glutsei and anastomoses with the lateral femoral circumflex artery. 

 Some branches pierce the Glutseus minimus and supply the hip-joint. 



The External Hiac Artery (A. Iliaca Externa) (Fig. 539). 



The external iliac artery is larger than the hypogastric, and passes obliquely 

 downward and lateralward along the medial border of the Psoas major, from the 

 bifurcation of the common iliac to a point beneath the inguinal ligament, midway 

 between the anterior superior spine of the ilium and the symphysis pubis, where 

 it enters the thigh and becomes the femoral artery. 



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

 areolar tissue, the termination of the ileum and frequently the vermiform process on the right 

 side, and the sigmoid colon 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 vessels in the 

 female, and occasionally by the ureter. The internal spermatic vessels lie for some distance 

 upon it near its termination, and it is crossed in this situation by the external spermatic branch 

 of the genitofemoral nerve and the deep iliac circumflex vein; the duct us deferens in the male, 

 and the round ligament of the uterus in the female, curve down across its medial side. Behind, 

 it is in relation with the medial border of the Psoas major, 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 medial side. Laterally, it rests against the Psoas major, from which it 

 is separated by the iliac fascia. Numerous lymphatic vessels and lymph glands lie on the front 

 and on the medial side of the vessel. 



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

 after the application of a ligature to the external iliac, are: the iliolumbar with the iliac circum- 

 flex; the superior gluteal with the lateral femoral circumflex; the obturator with the medial femoral 

 circumflex; the inferior gluteal with the first perforating and circumflex branches of the profunda 

 artery; and the internal pudendal with the external pudendal. When the obturator arises from 

 the inferior epigastric, it is supplied with blood by branches, from either the hypogastric, the 

 lateral sacral, or the internal pudendal. The inferior epigastric receives its supply from the 

 internal mammary and lower intercostal arteries, and from the hypogastric by the anastomoses 

 of its branches with the obturator. 1 



Branches. Besides several small branches to the Psoas major and the neighbor- 

 ing lymph glands, the external iliac gives off two branches of considerable size: 



Inferior Epigastric. Deep Iliac Circumflex. 



1 Sir Astley Cooper describes in Ouy'.s Hospital Reports, vol. i, the dissection of a limb eighteen years after successful 

 ligature of the external iliac artery. 



