THE INTERNAL ILIAC ARTERY 



577 



through the upper part of the sacro-sciatic Hsanient and runs jjackward and down- 

 ward on the latter under cover of the l)i('eps femoris (P'ig. 455). It gives 

 branches to that muscle and to the seniitendinosus and semimembranosus, 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 depressor and intertransversales muscles of the tail and 

 divides into two l)ranches which supi)l\' 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 nmscle. It gives branches to the ilio- 

 psoas and longissimus, and terminates by turning around the external border of the 



Common 

 ilioc irins 



Itilcrmil ilidc artcnj 

 ExUrnnl ilinc nrliry 

 Circumflex iliac arlcrij 

 External angle uf ilium 



Inguinal ligament 



Sartorius 



Femoral nerve 



Femoral vessels 



Internal circumflc 

 vessels 

 Trochanter tertius 



Obturator vessels 



Biceps femoris 

 Semitendinosus 

 Semimembranos us 



Fig. 456. — Deep Dissection of Ventral Wall of Pelvis of Horse (Male). 

 /, External pudic artery and small satellite vein; 2, anastomosis between external pudic and internal cir- 

 cumflex veins; 3, acce.s.sory ligament; 4< round ligament; 5, tran.sverse ligament; ff, head of femur; 7, obturator 

 externus (stumps); 5, inner margin of obturator foramen; 9, origin of gracilis; iO, origin of adductor; 11, hulho- 

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



ilium a little behind the external angle, giving branches to the gluteus medius 

 and tensor fasciae latse (Fig. 455). 



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 

 through the great sacro-sciatic foramen, dividing into several branches as it 

 emerges; these enter the gluteal muscles (Fig. 455). 



6. The iliaco-femoral or external circumflex artery (A. circumflexa femoris 

 lateralis) passes downward and outward across and beneath the shaft of the ilium, 

 under cover of the iliacus muscle, and dips in between the rectus femoris and 

 vastus externus. It is accompanied b}- two satellite veins. It gives collateral 

 branches to the iliopsoas, the glutei, and the tensor fasciae latse, supplies the 

 nutrient artery of the ilium, and terminates in the quadriceps femoris (Fig. 455). 



7. The obturator artery (A. obturatoria), the inner terminal branch of the 

 internal iliac, passes downward and backward on the pelvic surface of the shaft of 



37 



