THE ABDOMEN 843 



the inferior vesical. It is distributed to the rectum, and gives 

 branches to the vesicula seminalis, ampulla of the vas deferens, 

 and prostate gland. The anastomoses which it establishes are with 

 the superior hemorrhoidal of the inferior mesenteric, the inferior 

 hemorrhoidal of the internal pudic, the inferior vesical of its own 

 side, and its fellow of the opposite side. 



The obturator artery (P) passes along the outer wall of the pelvic 

 cavity on its way to the obturator canal, lying between the 

 parietal pelvic fascia and the peritoneum. It has the obturator 

 nerve above it, and its o\^ti vein below it. In entering the 

 obturator canal, by which it emerges from the pelvis, the artery 

 does not pierce the parietal pelvic fascia, but passes over its 

 upper border, where that joins the upper part of the obturator 

 membrane. As the artery passes along the pelvic wall it furnishes 

 the following branches : muscular to the obturator internus ; 

 iliac to the iliac fossa, which supply the bone, psoas magnus, and 

 iliacus, and anastomose with the iliac branch of the ilio-lumbar ; 

 vesical, which reaches the side of the bladder within the lateral 

 false ligament ; and fuhic to the back of the body of the os pubis, 

 where it anastomoses with the pubic branch of the deep epigastric 

 from the external iliac, and its fellow of the opposite side. 



For the distribution of the obturator artery outside the pelvis, 

 see p. 488. 



The obturator artery sometimes arises from the deep epigastric ; 

 see p. 426. 



The internal pudic artery (P) is one of the terminal branches of 

 the anterior division. It descends with the sciatic artery upon the 

 pyriformis and sacral nerves, and emerges from the pelvis through 

 the lower compartment of the great sacro-sciatic foramen, having 

 previously pierced the parietal pelvic fascia. The intrapelvic 

 branches of the vessel are unimportant, and are distributed to the 

 pyriformis, coccygeus, obturator internus, and pelvic fascia. For 

 the further course and distribution of the artery, see the gluteal 

 region and the perineum, pp. 433 and 622. 



The sciatic artery (P) is the other and larger terminal branch of 

 the anterior division. It descends, usually behind the internal 

 pudic, upon the pyriformis and sacral nerves, and emerges from 

 the pelvis through the lower compartment of the great sacro- 

 sciatic foramen, having previously pierced the parietal pelvic 

 fascia. Within the pelvis the artery gives off branches to the 

 pjrriformis, levator ani, coccygeus, rectum, bladder, vesicula 

 seminalis, and prostate gland. 



For the extrapelvic course and distribution of the vessel, see 



P- 432. 



Posterior Division. — The ilio-lumbar artery (P) passes upwards and 

 outwards in front of the sacro-iliac articulation, between the lumbo- 

 sacral cord and obturator nerve. In its course it passes behind the 

 external iliac, or, it may be, the common iliac, vessels, and also 

 behind the psoas magnus and iliacus. On reaching the back part 



