8io 



HUMAN ANATOMY. 



The variations of the smaller branches, which are quite numerous, will be considered in 

 connection with their description. It may be pointed out, however, that, since the superior 

 vesical artery is the persistent portion of the original hypogastric artery and primarily the 

 direct continuation of the hypogastric axis, some of the visceral branches which normally 

 arise from the axis may take their origin from the superior vesical. Furthermore, vessels which 

 embrj'ologically arise from one or other of the great branches of the hypogastric may, on account 

 of the variations in the origin of these, come to arise from the hypogastric axis. 



Practical Considerations. — The internal iliac artery is almost never the seat 

 of aneurism. It has been ligated for hemorrhage, for gluteal and sciatic aneurism, 

 and in the treatment of inoperable pelvic growths. It may be approached intraperi- 

 to7ieally by the same incision and the same general procedure as employed in 

 ligation of the common iliac {q.v.). The vein lies behind and to the inner side, and 



Fig. 725. 



Diagram illustrating four types of arrangement of branches from hypogastric (internal iliac) artery : ci. ei, 

 it, common, external and internal iliac artery; il, ilio-lumbar; /j, lateral sacral; ^.gluteal; s, sciatic; ip, 

 internal pudic ; ha, hypogastric axis. 



by reason of its size and its close proximity to the vessel must be very carefully dealt 

 with. The needle should be passed from within outward. The relation of the ureter, 

 which crosses the vessel obliquely from without inward and downward, and of the 

 hypogastric plexus should be borne in mind. 



In the extraperitoneal method the incision and procedure are just as in extra- 

 peritoneal ligation of the external iliac (page 819), except that the separation of the 

 peritoneum from the iliac fascia must be carried to a higher level. 



The collateral circtilation is carried on chiefly through («) the inferior mesen- 

 teric ; ((5) the circumflex iliac ; (r) the middle sacral ; (^) the deep femoral ; (<?) the 

 obturator and internal pudic of the opposite side, all of which carry blood from above 

 the ligature into (a) the hemorrhoidal branches of the internal iliac ; (^) the ilio- 

 lumbar ; (r) the lateral sacral ; (^ ) the sciatic and gluteal ; and (<?) the corresponding 

 vessels of the other side (z. e., the side of the ligature). 



I. The Ilio-Lumbar Artery. — The ilio-lumbar artery (a. ilio-lunibalis) 

 (Fig. 724) is most frequently given off from the main stem of the internal iliac, 

 shortly above its separation into the anterior and posterior divisions. Not infre- 

 quently, however, it is a branch of the posterior division. It passes upward and 

 outward towards the brim of the pelvis, crossing in front of the lumbo-sacral nep/e 

 and behind the external iliac artery, beyond which it passes beneath the psoas 

 muscle. On reaching the crest of the ilium it divides into two 



Branches. — [a) The lumbar branch (ramus lumbalis) is directed upward and backward be- 

 neath the psoas and supplies that muscle and the quadratus lumborum. It sends a spinal branch 

 {ramus spinalis) through the intervertebral foramen between the last lumbar and first sacral 

 vertebrae, and anastomoses with branches of the last lumbar artery. 



{b) The iliac branch (ramus ih'acus) passes outward beneath the psoas and ramifies upon 

 the surface of the iliacus muscle, supplying it and usually giving of? a nutrient branch to the 

 ilium. 



2. The Lateral Sacral Arteries. — The lateral sacral arteries (aa. sacrales 

 laterales) (Fig. 724) are usually two in number, and arise from the posterior division of 

 the internal iliac. The superior one passes downward and inward to the first anterior 

 sacral foramen, and passes through it to supply the spinal membranes and anastomose 



