Kidney left and right, which branch directly from the abdominal aorta. Despite their relatively small size, the kidneys receive approximately 20% of the cardiac output. Each renal artery branches into segmental arteries, dividing further into interlobar arteries, which penetrate the renal capsule and extend through the renal columns between the renal pyramids. The interlobar arteries then supply blood to the arcuate arteries that run through the boundary of the cortex and the medulla. Each arcuate artery supplies several interlobular arteries that feed into the afferent arterioles that supply the glomeruli. After filtration occurs, the blood moves through a small network of
Posterior spinal artery anastomosis around the posterior roots of the spinal nerves, and communicate, by means of very tortuous transverse branches, with the vessels of the opposite side. Close to its origin each posterior spinal artery gives off an ascending branch, which ends ipsilaterally near the fourth ventricle. The posterior spinal artery can often originate from the posterior inferior cerebellar artery, rather than the vertebral. Most cranially, the posterior spinal artery supplies the dorsal column of the closed medulla containing fasiculus gracilis, gracile nucleus, fasciculus cuneatus, and cuneate nucleus. At the spinal cord level, the posterior spinal artery supplies the dorsal and lateral