|Henry Gray (18251861). Anatomy of the Human Body. 1918.|
| The right common iliac artery (Fig. 539) is somewhat longer than the left, and passes more obliquely across the body of the last lumbar vertebra. In front of it are the peritoneum, the small intestines, branches of the sympathetic nerves, and, at its point of division, the ureter. Behind, it is separated from the bodies of the fourth and fifth lumbar vertebræ, and the intervening fibrocartilage, by the terminations of the two common iliac veins and the commencement of the inferior vena cava. Laterally, it is in relation, above, with the inferior vena cava and the right common iliac vein; and, below, with the Psoas major. Medial to it, above, is the left common iliac vein.|
| The left common iliac artery is in relation, in front, with the peritoneum, the small intestines, branches of the sympathetic nerves, and the superior hemorrhoidal artery; and is crossed at its point of bifurcation by the ureter. It rests on the bodies of the fourth and fifth lumbar vertebræ, and the intervening fibrocartilage. The left common iliac vein lies partly medial to, and partly behind the artery; laterally, the artery is in relation with the Psoas major.|
Branches.The common iliac arteries give off small branches to the peritoneum, Psoas major, ureters, and the surrounding areolar tissue, and occasionally give origin to the iliolumbar, or accessory renal arteries.
Peculiarities.The point of origin varies according to the bifurcation of the aorta. In three-fourths of a large number of cases, the aorta bifurcated either upon the fourth lumbar vertebra, or upon the fibrocartilage between it and the fifth; the bifurcation being, in one case out of nine, below, and in one out of eleven, above this point. In about 80 per cent. of the cases the aorta bifurcated within 1.25 cm. above or below the level of the crest of the ilium; more frequently below than above.
| The point of division is subject to great variety. In two-thirds of a large number of cases it was between the last lumbar vertebra and the upper border of the sacrum; being above that point in one case out of eight, and below it in one case out of six. The left common iliac artery divides lower down more frequently than the right.|
| The relative lengths, also, of the two common iliac arteries vary. The right common iliac was the longer in sixty-three cases; the left in fifty-two; while they were equal in fifty-three. The length of the arteries varied, in five-sevenths of the cases examined, from 3.5 to 7.5 cm.; in about half of the remaining cases the artery was longer, and in the other half, shorter; the minimum length being less than 1.25 cm., the maximum, 11 cm. In rare instances, the right common iliac has been found wanting, the external iliac and hypogastric arising directly from the aorta.|
Collateral Circulation.The principal agents in carrying on the collateral circulation after the application of a ligature to the common iliac are: the anastomoses of the hemorrhoidal branches of the hypogastric with the superior hemorrhoidal from the inferior mesenteric; of the uterine, ovarian, and vesical arteries of the opposite sides; of the lateral sacral with the middle sacral artery; of the inferior epigastric with the internal mammary, inferior intercostal, and lumbar arteries; of the deep iliac circumflex with the lumbar arteries; of the iliolumbar with the last lumbar artery; of the obturator artery, by means of its pubic branch, with the vessel of the opposite side and with the inferior epigastric.
1. The Hypogastric Artery
(A. Hypogastrica; Internal Iliac Artery)
The hypogastric artery (Fig. 539) supplies the walls and viscera of the pelvis, the buttock, the generative organs, and the medial side of the thigh. It is a short, thick vessel, smaller than the external iliac, and about 4 cm. in length. It arises at the bifurcation of the common iliac, opposite the lumbosacral articulation, and, passing downward to the upper margin of the greater sciatic foramen, divides into two large trunks, an anterior and a posterior.
Relations.It is in relation in front with the ureter; behind, with the internal iliac vein, the lumbosacral trunk, and the Piriformis muscle; laterally, near its origin, with the external iliac vein, which lies between it and the Psoas major muscle; lower down, with the obturator nerve.
| In the fetus, the hypogastric artery is twice as large as the external iliac, and is the direct continuation of the common iliac. It ascends along the side of the bladder, and runs upward on the back of the anterior wall of the abdomen to the umbilicus, converging toward its fellow of the opposite side. Having passed through