The Kidneys are a pair of organs placed on the posterior wall of the abdomen, which secrete the urine: the urine is carried by means of the ureter to the bladder, situated in the pelvis, which opens to the exterior by means of the urethra.

They are bean-shaped organs lying on the posterior wall of the abdomen, with their long axes vertical and the hilus placed towards the middle line. The position of the kidneys varies somewhat with the individual, but as a rule the right kidney is at a lower level than the left. The greater part of the kidneys lies to the inner side of a line drawn vertically upwards from the mid-point of Poupart's ligament (this is not the same as the mid-Poupart plane). The posterior surface of the kidney is closely applied to the diaphragm, psoas, and quad-ratus lumborum muscles, and tendon of transversalis in front of the twelfth rib and transverse processes of the first three lumbar vertebrae. The lower end is usually from 1 1/2 to 2 inches above the crest of the ilium, and is farther from the middle line than the upper. The kidneys lie entirely behind the peritoneum, and are held in position by a quantity of fat. The kidney is slightly rotated in position so that the hilus projects forward.

On the upper end of each kidney is a ductless gland, the suprarenal capsule (described above).

The relations of the anterior surface differ on the two kidneys. The right kidney has on its anterior surface, above and internally, the suprarenal capsule. Below that a large part of the surface is in contact with the visceral portion of the liver, and below that the kidney is in contact with the duodenum and the beginning of the transverse colon.

On the anterior surface of the left kidney, above and internally, is the impression of the suprarenal capsule; just below is a small surface in contact with the stomach, and below again the pancreatic surface. To the right of these there is the gastric surface, and the lower end is in contact with the jejunum in-ternally and the transverse colon externally.

At the hilus below the renal artery is the pelvis of the kidney- a thin-walled funnel-shaped sac formed by the junction of several calyces inside the kidney; the pelvis rapidly narrows to form the ureter.

Ureter

The Ureter is a duct with a small lumen and thick muscular walls. It is about 9 inches in length. The upper half or rather more lies in the abdominal cavity, the rest in the pelvis. The ureter passes downwards and inwards lying on psoas, and, crossing the iliac artery, it enters the pelvis. It then passes down on the side wall of the pelvis under the peritoneum, curving backwards close to the great sciatic notch. At the level of the ischial spine it bends inwards and enters the bladder about an inch from the middle line.