INTERNAL ILIAC ARTERY, AND ITS BRANCHES. 231 



quadratus lumborum, it distributes branches: it also sends rami- 

 fications into the spinal cavity, and anastomoses with the lower 

 lumbar arteries; sometimes it supplies the place of the last lU-m- 

 bar entirely. The inferior branch, going outwardly, is divided 

 into two orders of ramifications which supply the iliacus inter- 

 nus muscle, on its surface and more deeply; also the os ilium by 

 a ramuscle which penetrates the nutritious foramen of the latter. 

 The inferior branch anastomoses with the circumflexa ilii of the 

 external iliac. 



The Lateral Sacral Arteries (Arteries Sacrce Lateraks) arise 

 next, either from the hypogaslric or from its posterior trunk: 

 their number is commonly equal to that of the foramina on the 

 side of the sacrum in front, though they come from only one or 

 two roots. They cross the front of the sacrum, and divide into 

 branches, some of which anastomose with the middle sacrat 

 artery, while others enter the foramina of the sacrum, to be 

 spent on the lower part of the cauda equina. 



The Obturator Artery (Arterla Obturatoria) comes common- 

 ly from the hypogastric or from one of its principal trunks; in 

 some cases it arises from the epigastric or from the external 

 iliac, near Poupart's ligament. In the first cases it passes for- 

 wards parallel with the brim of the pelvis, and in the latter 

 cases it descends behind the superior ramus of the pubes. 

 Whatever may be the condition of its origin, it gets from the 

 pelvis through the upper part of the thyroid foramen over the 

 superior margin of the obturator internus muscle, having pre- 

 viously sent off some inconsiderable ramifications to the peri- 

 osteum and the contiguous muscles. 



It emerges from the pelvis on the upper margin of the obtu- 

 rator externus muscle, and then divides into two principal 

 trunks. The posterior descends along the external margin of 

 the obturator externus muscle, to which it gives ramifications; 

 it likewise sends some branches to the heads of the muscles 

 coming from the tuber of the ischium, and thereby anastomoses 

 with the sciatic artery; other branches are spent upon the hip 

 joint, one of which gets into the cavity of the latter through 

 the notch at the lower part of the aeetabulum, and is spent 

 upon the adipose matter in its bottom. The anterior branch 



