THE HYPOGASTRIC ARTERY 605 



The Right Common Iliac Artery 



The right common iliac measures about 5 cm. (2 in.) in length, and is rather 

 longer than the left, in consequence of the aorta bifurcating a little to the left of 

 the median line. 



Relations. — In front it is covered by the peritoneum, and is crossed by the right ureter a 

 little before its bifurcation, by the ovarian artery in the female, by the termination of the ileum, 

 by the terminal branches of the superior mesenteric artery, and by branches of the sympathetic 

 nerve descending to the hypogastric plexus. 



Behind, it hes on the right common iliac vein, the end of the left common iliac vein, and the 

 commencement of the inferior vena cava, which separate it from the fourth and fifth lumbar 

 vertebrae and their intervening disc, the psoas muscle, and the sympathetic nerve; whilst still 

 deeper in the groove between the fifth vertebra and the psoas are the lumbo-sacral trunk, 

 the obturator nerve, and the ilio--lumbar artery. 



To the right side are the beginning of the inferior vena cava, the end of the right common 

 iliac vein, and the psoas muscle, which, however, is separated from the artery by the vena cava 

 inferior at its upper part. 



To the left side are the right common ihac vein, the termination of the left common iliac vein, 

 and the hypogastric plexus. 



The Left Common Iliac Artery 



The left common iliac artery, 4 cm. (14 in.) in length, is a little shorter and 

 thicker than the right. 



Relations, — In front it is covered by the peritoneum, which separates it from the intestines, 

 and is crossed by the ureter, the ovarian artery in the female, branches of the sympathetic nerve 

 descending to the hypogastric plexus, the termination of the inferior mesenteric artery, the 

 sigmoid colon, and the sigmoid mesocolon. 



Behind are the lower border of the body of the fourth lumbar vertebra, the disc between the 

 fourth and fifth lumbar vertebra, the body of the fifth lumbar vertebra, and the disc between it 

 and the sacrum. Crossing deeply behind the artery between the fifth lumbar vertebra and the 

 psoas, is the obturator nerve, the lumbo-sacral trunk, and the ilio-lumbar artery. 



To the left side is the psoas muscle. 



To the right side are the left common iliac vein, the hypogastric plexus, and the middle 

 sacral artery. 



Collateral Circulation 



The collateral circulation after obstruction or ligature of the common iliac artery is carried 

 on chiefly (fig. 497) by the anastomosis of the middle sacral with the lateral sacral; the internal 

 mammary with the epigastric; the lumbar arteries of the aorta with the ilio-lumbar and deep 

 circumflex iliac; the pubic branch of the epigastric with the pubic branch of the obturator; the 

 posterior branches of the sacral arteries with the superior gluteal (gluteal) ; the superior haem- 

 orrhoidal from the inferior mesenteric, with the hsemorrhoidal branches of the hypogastric (in- 

 ternal iliac) and pudic; the ovarian arteries from the aorta with the uterine branches of the hy- 

 pogastric (internal iliac) ; and by the anastomosis across the middle line of the pubic branch of 

 the obturator with the like vessel of the opposite side; the lateral sacral with the opposite 

 lateral sacral; and the vesical, haemorrhoidal, uterine, and vaginal branches of the hypogastric 

 with the corresponding branches of the opposite hypogastric (internal iliac). 



Branches of the Common Iliac Artery 



The branches of the common iliac artery are:— (1) The hypogastric (internal 

 ihac) ; and (2) external ihac. 



There are a few small, unimportant branches distributed to the peritoneum and subperi- 

 toneal fat. They anastomose with vessels given off from the lumbar, inferior phrenic, and renal 

 arteries, forming a subperitoneal arterial anastomosis. The ureter receives small insignificant 

 twigs as it crosses the artery. They anastomose with the ureteral arteries given off from the 

 internal spermatic above, and with those derived from the vesical arteries below. 



THE HYPOGASTRIC ARTERY 



The hypogastric or internal iliac artery [a. hypogastrica], arises at the bifur- 

 cation of the common iliac opposite the lumbo-sacral articulation. It descends 

 into the pelvis for about 3 cm. (1| in.) and then divides, opposite the upper 

 margin of the great sciatic foramen, into an anterior and a posterior division. 

 The anterior division commonly gives off the obturator, inferior gluteal, umbilical, 



