Kidneys, ureters, and bladder
The kidneys are situated in the perirenal space, which is enclosed by the anterior (Gerota) and posterior renal fasciae and located on the posterior abdominal wall on each side of the vertebral column. The kidney’s three-dimensional orientation is parallel to the lateral border of the psoas muscle with the long axis and adjacent to the quadratus lumbar muscle. The right kidney usually lies slightly lower than the left kidney because of the right lobe of the liver. Normal kidneys measure 11 cm (10th–90th percentile, 9.8, 12.3) and 5.8 cm (10th–90th percentile, 5.1, 6.4) with decreasing size at an older age (Emamian et al. 1993). The kidney shows a bean-shaped structure with a superior and an inferior pole and a hilum, where the renal artery, renal vein, and ureter are located. The organ is covered by the renal capsule containing cortex and medulla (renal parenchyma) and the renal sinus (vasculature, lymphatic system, and collecting system).
