Kidney structure with a convex and a concave border. A recessed area on the concave border is the renal hilum, where the renal artery enters the kidney and the renal vein and ureter leave. The kidney is surrounded by tough fibrous tissue, the renal capsule, which is itself surrounded by perirenal fat, renal fascia, and pararenal fat. The anterior (front) surface of these tissues is the peritoneum, while the posterior (rear) surface is the transversalis fascia. The superior pole of the right kidney is adjacent to the liver. For the left kidney, it is next to the spleen. Both, therefore, move
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