672 BLOOD-VASCULAR SYSTEM OF THE HORSE 
ventral sacral foramina. They give off branches to the spinal cord and its mem- 
branes, which reinforce the ventral spinal artery, and others which emerge through 
the dorsal sacral foramina and supply the muscles and skin of the croup. 
(2) The middle coccygeal artery (A. coccygea) is an unpaired vessel which 
arises from the right or left lateral sacral or from a lateral coccygeal artery. It 
passes backward on the pelvic surface of the sacrum to the median line and con- 
tinues in that position along the tail between the ventral muscles, supplying 
these and the skin. 
(83) The posterior gluteal artery (A. glutea caudalis)! emerges through the 
upper part of the sacro-sciatic ligament and runs on the latter toward the tuber 
ischu, under cover of the biceps femoris (Fig. 580). It gives branches to that 
Common 
iliac veins 
Internal iliac artery sae 
External iliac artery So 
Circumflex iliac artery 
Tuber core 
Femoral vessels 
Remnant of 
inguinal ligament 
Sartorius 
Femoral nerve - 
Deep femoral 
vessels 
Trochanter terlius - 
Biceps femoris 
Semitendinosus 
Semimembranosus 
Fig, 581.—Deep Dissection oF VENTRAL WALL OF PELVIs OF Horse (MALE) 
1, External pudie artery and small satellite vein; 2, anastomosis between external pudic vein and deep femoral 
veins; 3, accessory ligament; 4, round ligament; 4, transverse hgament; 6, head of femur; 7, obturator externus 
(stumps); 4. medial margin of obturator foramen; 9, origin of gracilis; 70, origin of adductor; 11, bulbocavernosus; 
12, retractor penis; 13, suspensory ligament of penis. (After Schmaltz, Atlas d. Anat. d. Pferdes.) 
muscle, the semitendinosus, semimembranosus, superficial gluteus, and coceygeus, 
and anastomoses with the obturator, deep femoral, and posterior femoral arteries. 
(4) The lateral coccygeal artery (A. caudalis lateralis ventralis) continues the 
direction of the lateral sacral, but is much smaller than the preceding vessel. It 
passes back between the ventral and intertransversales muscles of the tail and 
divides into dorsal and ventral branches which supply twigs to the muscles and 
skin. 
4. The ilio-lumbar artery (A. iliolumbalis) arises at a right angle from the 
internal iliac and runs outward behind the sacro-iliac joint, crossing the ventral 
surface of the ilium under cover of the iliacus muscle. It gives branches to the ilio- 
psoas and longissimus, turns around the lateral border of the ilium a little behind 
the tuber coxe, and ends in the gluteus medius and tensor fascie late (Fig. 580). 
5. The anterior gluteal artery (A. glutea cranialis) is the largest branch of the 
internal iliac. It arises usually opposite to the preceding vessel, and passes outward 
1 Also termed the ischiatic artery. 
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