EXTERNAL ILIAC ARTERIES. 411 



pudic artery furnishes branches to the rectum, vulva, and vaginal 

 bulb, together with the analogue of the vesico-prostatic in the 

 male — the vaginal artery, which anastomoses with the uterine, 

 supplying also the bladder. The perineal artery in the female 

 supplies the vulva. 



The Ilio-luivibar artery is given off at a right angle, passing 

 between the iliacus muscle and the venter surface of the ilium. 

 It supplies the sacro-iliac articulation, the sublumbar muscles, and 

 surmounting the iliac crest, becomes buried in the gluteus maximus. 



The Iliaco-femoral artery, large in the horse, passes down- 

 wards and outwards, crossing the iliacus, .to supply the crural 

 triceps and tensor fasciae latae from the outside. 



The Obturator artery is sometimes regarded as having a 

 common origin with the iliaco-femoral, sometimes, and more 

 correctly as being given off by the latter. It is a long vessel 

 passing back^'ards and downwards, along the lower edge of the 

 pyriformis muscle, and through the obturator foramen, when it 

 divides into cavernous and crural branches, the first going to 

 the dorsum, the other to the bulb and crus of the penis. It 

 gives en route an inferior braoch to the ischio-tibial muscles. 



The Gluteal artery is the largest branch of the group, and 

 passes along the pelviq roof downwards, and through the great 

 sciatic notch, along with the great sciatic nerve. It supplies the 

 gluteal muscles, anastomosing with the ilio-lumbar. 



The Lateral sacral artery runs straight backwards along 

 the side of the sacrum near its inferior foramina, through which 

 it sends in the sacrospinal branches to supply the spinal cord. 

 It finally divides into ischiatic and lateral coccygeal; the former 

 winds outwards behind the sacro-sciatic ligament, and breaks up 

 in the ischio-tibial muscles, anastomosing with ascending twigs 

 of the femoro-popliteal, deep femoral, and obturator arteries. 

 The lateral coccygeal branch is continued backwards, supplying 

 the tail : a x^iiddle coccygeal branch is given off usually from the 

 light or left lateral sacral artery, perhaps cftener from the left. 



external iliac arteries. 



(Fig. 157. b.) 



These, the anterior or external branches of the aortic quadri- 

 furcation, are essentially the arteries of the pelvic limb. Each of 

 them arises below the last lumbar vertebra, curving obli(juely 



