672 



BLOOD-VASCULAH SYSTEil 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. 



(3) 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 

 ischii, under cover of the biceps femoris (Fig. 580). It gives branches to that 



Common 

 iliac veins 



Internal iliac artery 



External iliac artery 

 Circumflex iliac artery 

 Tubn eoiee 



Remnant of 



inguinal ligamint 



Sartot I n s 



Femoral ni ne 



Deep femoial 



visstU 



Trochanter tottii 



Ohtunitoi I 



Diet ps /( /rtfi/d 



Setnitemhnosui 



Semimtnihranosus 



Fig. 581. — Deep Dissection of Ventral Wall of Pelvis of Horse (Male). 

 1, External pudic artery and small satellite vein; 2, anastomosis between external pudic and deep femoral veins; 

 3, accessory ligament: J^, round ligament; 5, transverse ligament; 6, head of femur; 7, obturator externus (stumps); 

 5, medial margin of obturator foramen; 5, origin of gracilis; iO, origin of adductor; ^i, bulbocavernosus; i;?, retractor 

 penis; 13, suspensory ligament of penis. (After Schmaltz, Atlas d. Anat. d. Pferdes.) 



muscle, the semitendinosus, semimembranosus, superficial gluteus, and coccygeus, 

 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 coxee, and ends in the gluteus medius and tensor fasciae latee (Fig. 580) . 



5. The anterior gluteal artery (A. glutea craniahs) is the largest branch of the 

 internal iliac. It arises usually opposite to the preceding vessel, and passes outward 



' Also termed the ischiatio artery. 



