326 SPECIAL ANATOMY. 



fifth lumbar vertebra, the sacrum coccyx, behind the rectum. Branches : pass off 

 laterally over the separate vertebrae to the bones and periosteum, and anas- 

 tomose with artt. sacra laterales ; on the basis of coccyx arched. 



575. C. Iliacce communes, the common Iliac arteries. 



Origin : before the fourth lumbar vertebra these two principal 

 trunks pass off from the anterior wall of aorta abdominalis, at an 

 acute angle (in the male=65, in the female=75). Course : 

 extending, downwards and outwards and rather backwards, about 

 two inches long ; between them a triangular space, the base of 

 which is situated at the inferior border of the fifth lumbar vertebra. 

 Position : behind the peritoneum and ureter (crossing with the 

 last), on the inner side of in. psoas, on the left side of Vv. iliacce 

 communes ; surrounded by lymphatic glands. The right passes 

 over V. iliac, commun. sinistra to the inner side of V. iliac, 

 commun. dextra. The left passes from the commencement on the 

 left (external) side of the vein, and is in front covered by Art. 

 hcemorrhoidalis interna. Branches : small to the Vv. iliacce, 

 communes and lymphatic glands, otherwise none. Each Art. 

 iliac, commun. divides rather above Symphysis sacro-iliaca 

 into two terminal branches : Art. hypogastrica and cruralis. 



576. I. Hypogastrica s. Iliaca interna, the internal Iliac artery, 



the internal branch rf iliaca cammun., passes at first rather down- 

 wards and forwards, then slightly curved, before symphysis sacro- 

 iliaca into the small pelvis, and divides, after a course of an inch 

 to an inch and a half, either into two (an anterior and a posterior) 

 or into eight (in the female ten) branches. Position : behind the 

 peritoneum, on the left side the Vv. hypogastr., A. hypog. sinistra 

 passes over V. iliaca com. sinistra, inwards. 



577. Anterior branches : 



1. Umbilicalis, the umbilical artery of the embryo. Vesicalis, the vesical 

 artery of adults. 



The umbilical arteries, very large in the embryo, the blood of which they 

 carry to the placenta, pass downwards, curved forwards and outwards, to the 

 sides of the urinary bladder, upwards and inwards to the umbilical ring, from 

 which they pass out into the umbilical cord and placenta, winding round the 

 Vena umbilicalis spirally. After birth the portion between the naval and 

 urinary bladder is closed, and froms the lig. laterale vesica. From which 

 piece, still open and with thick walls (art. vesicalis) arise: 



1. Artt. vesicales. a. Posterior on the posterior wall of the bladder from the 

 base to the vertex, b. Anterior on the anterior surface, often arises from 



