The Right Common Iliac Artery descends obliquely to the right side, till it reaches the superior extremity of the sacroiliac symphysis. Its posterior surface in this course lies on the cartilage between the fourth and fifth lumbar vertebrae; on the body of the last-named vertebra, and on the anterior common ligament which is interposed between these parts and the artery: it then lies on the bifurcation, or, more properly speaking, on the commencement of the inferior vena cava, and consequently on both the left and right common iliac veins as they unite to form, by their conflux, the origin of this large vein. In fact, almost immediately after its origin the right common iliac artery is borne off the spine by the large veins which lie behind it. Its right or corresponding vein not only lies behind it, but projects above to its outside, whilst lower down, part of the vein appears on its inner side: the sympathetic nerve, and still more deeply seated the obturator nerve, descend behind it into the pelvis. We may observe a deep groove situated between the inner edge of the psoas magnus and the spine, and it is in this groove that we expose the obturator nerve : by continuing our dissection still deeper in this locality we come upon the lumbo-sacral nerve on its way into the pelvis, and upon the lumbar division of the ilio-lumbar branch of the internal iliac artery. Its anterior surface is covered by the peritoneum; it is crossed obliquely at its bifurcation into the internal and external iliac arteries, by the ureter; and it is covered by the last coil of the ileum, as it ascends from the true pelvis to join the caecum in the right iliac fossa. In the female the spermatic vessels turn over it to reach the uterus.