230 CIRCULATORY SYSTEM. 



SECT. VI. OF THE PRIMITIVE ILIAC ARTERIES, AND THEIR BRANCHES. 



The Primitive Iliac Arteries, (Art. lliacce Primitive, com- 

 munes,) one on each side, are, as mentioned, the terminating 

 trunks of the abdominal aorta. They extend from the lower 

 part of the fourth lumbar vertebra to the sacro-iliac junction, or 

 near it, where they divide*into two trunks, the Internal and the 

 External Iliac. 



The primitive iliac is bounded on the outer side by the psoas 

 magnus muscle, and behind by the primitive iliac vein; it is 

 crossed at its lower part by the ureter. No branches deserving 

 of especial notice are sent from it before it bifurcates ; such as 

 exist are very small, and go simply to the parts immediately 

 contiguous. The right artery crosses in front of the root of the 

 left iliac vein. 



SECT. VII. OF THE INTERNAL ILIAC, OR HYPOGASTRIC ARTERY. 



The Internal Iliac Artery (Art. lliaca Internet, Hypogastrica) 

 descends from the front upper part of the sacro-iliac junction, 

 to the lower part of the same articulation. In this descent, it 

 is bounded behind by the sacral plexus of nerves, and gives off 

 several arterial trunks; but the manner by which the last is ac- 

 complished is much varied in different subjects. For the most 

 part, it is an inch or more long before any important branches 

 leave it; it is then frequently divided into two principal trunks, 

 an anterior and a posterior, from which proceed the several 

 branches that supply the internal and the external parts of the 

 pelvis. The rule of origin of the secondary trunks from these 

 two principal ones, even when the latter exist, is not fixed ; for 

 sometimes they arise from one, sometimes from the other, and 

 then again from the trunk of the hypogastric itself. 



The Ilio-Lumbar Artery (Art. Ilia Lumbaris) is commonly the 

 first branch of the hypogastric, or of its posterior trunk. It as- 

 cends outwards and backwards behind the psoas magnus mus- 

 cle, and there divides into two branches, a superior and an in- 

 ferior. The former continues to ascend between the psoas 

 magnus and the iliacus intjrnus muscle, to which, and to the 



