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THE INTERNAL ILIAC ARTERY 669 
and obliquus internus abdominis, gives branches to these muscles, and ends in the 
obliquus externus, the cutaneus, and the skin of the flank. 
THE INTERNAL ILIAC ARTERY 
The internal iliac or hypogastric arteries (Aa. hypogastrice) result from the 
bifurcation of the aorta under the fifth or sixth lumbar vertebra. They diverge 
at an angle of about 60 degrees, and each passes backward under the wing of the 
sacrum, then inclines downward on the pelvic surface of the shaft of the ilium, 
along the ventral border of the iliac head of the obturator internus, and divides a 
Coccygeus muscle 
Anal lymph glands 
Branch of posterior gluteal 
artery 
Posterior hemorrhoidal 
nerve 
Vulvar branch of 
pudic nerve 
Internal pudic 
artery 
Branch of pu- 
dic nerve to 
clitoris 
Obturator artery 
Fic. 578.—Dtssection oF PERINEUM OF MARE. 
1, Sacro-coceygeus dorsalis; 2, sacro-coccygeus lateralis; 3, intertransversales: 4 
recto-coccygeus; 6, 
, Sacro-coccygeus V’ 
hincter ani externus; 6’, branch connecting sphincter ani with constrictor vulvz; 7, 
bulb; 8, tuber ischii; 9, sacro-sciatic ligament. (After Schmaltz, Atlas d. Anat. d. Pferdes. 
little (ca. 2 em.) above the psoas tubercle into iliaco-femoral and obturator arteries. 
The chief branches are as follows: 
1. The last pair of lumbar arteries pass up through the foramina at the junc- 
tion of the last lumbar vertebra and the sacrum and are distributed as already 
described. 
2. The internal pudic artery (A. pudenda interna) arises near the origin of the 
internal iliac. It passes backward and somewhat downward, at first along the 
ventral border of the iliac head of the obturator internus, then above the superior 
ischiatic spine on the deep surface of the sacro-sciatic ligament, perforates the latter 
and runs for a variable distance in its substance or on its lateral face. It then re- 
enters the pelvic cavity, passes backward on the retractor ani to the ischial arch, 
and divides into the perineal artery and the artery of the bulb in the male, perineal 
and artery of the clitoris in the female. It is accompanied posteriorly by the 
pudic nerve. Its chief branches are as follows: 
