Belonging to the ilia. The iliac arteries are formed by the bifurcation of the aorta, at about the fourth vertebra of the loins. They descend nearly three fingers breadth from their origin; and when they arrive at the psoas muscle, on each side, or are upon it, each divides into two, an external and an internal: the external hath no particular name; the internal is called hy/iogastrica. See Hypogastricae Arteriae.

The external iliac, on each side, runs down to the ligamentum Fallopii, under which it goes out of the abdomen. In this course, it gives off a few small arteries to the peritonaeum, and parts near it; but, as it passes out of the belly, under the ligament, it detaches two considerable branches, one internal, the other external: the inner is called Epigastrica, q. v.; the external, Innominata, q. v. The external iliaca also gives off a small branch internally, under the ligament, which runs to the vagina or the spermatic chord, and sometimes another from the outside of the os ilium.

For the internal iliac artery, see Hypogastricae arteiae.

Iliacae venae, (from the same). Iliac veins, titillares vena, are formed by the bifurcation of the vena cava, about the last vertebra of the loins. After their leaving the vena cava, each divides into two principal branches; the iliaca externa, or anterior; and the iliaca interna, or posterior: the external, which seems the true continuation of the trunk, is sometimes simply named iliaca; the internal hypogastrica: each follows the course of the respective arteries. The external iliac veins lie a little on the inside of the arteries, and, before they leave the abdomen, they accompany their corresponding arteries, both in their course and in their divisions into branches.