624 THE ARTERIES. 



Extending from the body of the last lumbar vertebra, to near the terminal 

 insertion of the small psoas muscle, in an oblique direction downwards, outwards, 

 and backwards, the arteries are related : in front, with the trunks of the common, 

 iliac veins, which separate them from the external iliacs ; inwards, to the peri- 

 toneum ; above and outwards, to the sacro-iliac articulation and to the ilium. 



In its course, the internal iliac artery emits the following branches : the 

 umbilical artery, artery of the bull), ileo-lumbar gluteal, and subsacral arteries. At 

 its terminal extremity, it is divided into two branches which ride on the superior 

 border of the tendon belonging to the small psoas muscle — the one within, the 

 other without that tendon. The first is the obturator artery, the second the 

 ileo-femoral artery. All these branches will be studied in the order of their 

 enumeration. 



Preparation of the internal iliac artery. — Place the subject in the first position ; remove one 

 of tlie posterior limbs, leaving the rectum and bladder in the pelvis, and slightly inflating the 

 latter organ. Dissect, on the side from wliich the limb lias been removed, the origin and 

 visceial ramifications of the branches furnished by the trunk of the artery. Follow, on the 

 opposite side, the ramifications given off by these branches to the muscles. To conveniently 

 prepare the coccygeal arteries, it is necessary, after removinir the great sciatic ligament and 

 dissecting the internal artery of the bulb along with the subsacral trunk, to raise up the 

 rectum and bladder by means of the chain-hooks. 



1. Umbilical Aetery (Figs. 368, 5 ; 370, 3). 



This artery forms a considerable vessel during foetal life, and carries the blood 

 of the foetus to the placenta ; it will be described in detail in the anatomy of the 

 foetus. 



In the adult it is almost entirely obliterated, appearing only as a fibrous cord 

 extending from the internal iliac artery uo the fundus of the bladder, and placed ■ 

 at the free margin of the lateral serous fold detached from the fundus of that 

 organ. This cord throws off on its track one or more vesical branches, beyond 

 which its canal altogether disappears. These vesical branches also — though very 

 rarely— come from the internal pudic artery ; in which case the obliteration of the 

 umbilical artery is complete. 



2. Internal Pudic Artery, or Artery of the Bulb (Figs. 368, 16 ; 370, 4) 



This vessel differs in its distribution in the male and female. 

 Internal Pudic Artery in the Male. — It proceeds from the internal iliac, 

 near the origin of that vessel, by a trunk common to it and the umbilical artery ; 

 it is then directed backwards, following the superior border of the pyriformis 

 muscle, and placed either without or within the texture of the sacro-sciatic liga- 

 ment. Arrived at the neck of the bladder, it enters the pelvic cavity, lying beside 

 the prostate and Cowper's glands, and is finally inflected downwards, passing 

 round the ischial arch to reach the bulb of the urethra. 

 In its progress it furnishes : 



1. Insignificant ramuscules to the muscle adjoining the sacro-sciatic ligament, 



2. The vesico-prostatic artery (Figs. 338, 8 ; 368, 17). This is a branch con- 

 stant in its distribution, but variable in its origin. Destined to supply the pros- 

 tate gland, vesiculae seminales, the pelvic dilatation of the vas deferens and the 

 canal itself, as well as the bladder, it usually commences near the prostate gland, 

 and passes backwards, in a flexuous manner, on the vesiculae seminales and the 

 vas deferens. 



