456 ABDOMEN 



Arteria Hsemorrhoidalis Media. The middle hsemor- 

 rhoidal artery may arise independently or in common with the 

 inferior vesical, and it may pass in front of the lower part of the 

 ureter or behind it. It is distributed mainly to the muscular 

 coat of the rectum, where it anastomoses with the superior and 

 inferior haemorrhoidal vessels. It supplies twigs also to the pro- 

 state, the deferent ducts, the seminal vesicles, and the bladder. 



Arteria Obturatoria. The obturator artery runs forwards 

 on the inner aspect of the pelvic wall to the upper margin 

 of the obturator foramen, where it enters the obturator 

 canal. In the pelvis it lies in the extraperitoneal fat below 

 the obturator nerve and above the vein. It gives some small 

 iliac branches to the iliac fossa, and a pubic branch, which 

 ascends on the pelvic surface of the pubis to anastomose 

 with the pubic branch of the inferior epigastric artery. The 

 anastomosis, if formed, may become converted into either the 

 commencement of the obturator, which then arises from the 

 inferior epigastric, or the commencement of the inferior epi- 

 gastric, which then arises from the obturator, and, in either 

 case, it may pass to the medial side or to the lateral side of 

 the femoral ring ; thus it attains a close relationship with a 

 femoral hernia. (See p. 260.) 



Arteria Pudenda Interna (O.T. Internal Pudic Artery). 

 In the pelvis minor the internal pudendal artery proceeds 

 downwards in front of the piriformis muscle and the sacral 

 nerves. As it leaves the pelvis minor it passes between the 

 piriformis and the coccygeus muscles, and through the lower 

 part of the greater sciatic foramen. 



Arteria Grlutsea Inferior (O.T. Sciatic Artery). The 

 inferior gluteal artery is usually the largest branch given of 

 by the anterior division of the hypogastric artery, and, as a 

 rule, it lies behind the internal pudendal. It passes down in 

 front of the piriformis muscle and the sacral plexus, and 

 frequently through one of the loops of the plexus. It leaves 

 the pelvis by passing between the piriformis and coccygeus 

 muscles, and through the lower part of the greater sciatic 

 foramen (Fig. 216). 



Arteria Ilio-lumbalis. The ilio-lumbar artery springs 

 from the posterior division of the hypogastric artery and 

 passes upwards, laterally, and backwards, behind the obturator 

 nerve, the external iliac vessels, and the psoas major muscle, 

 into the iliac fossa, where it divides into lumbar and ilij 



