Anatomical Region of Kidney- Study of Kidney, Kidney Anomalies and its variations. ( Jamal Bajwa)

The Kidney is an organ in the body and is located in the rear end of the abdominal cavity in the retroperitoneal space. The kidneys lie bilaterally to the vertebral column between thoracic vertebrae 12 and lumbar 13. They lie posteriorly to the diaphragm and are roughly 12cm long and 3cm thick and is a distinct “C shaped” organ. It weighs roughly between 135-150g depending on gender. The kidney has several essential regulatory roles; one of its many functions is to filter the blood via osmosis. The kidney receives blood from the renal arteries which arise off the side of the abdominal aorta, immediately below the superior mesenteric artery. The kidneys drain into the renal veins which lie anterior to the corresponding arteries and join with the inferior vena cava. The kidney also excretes waste through the ureter which drains into the urinary bladder. The ureter is also a paired structure which arises from the renal pelvis on the medial aspect of each kidney. The kidney filters out salts produced in the body and wastes caused by protein metabolism. It also returns back important nutrients and chemicals back to the blood. It produces hormones including adrenalin, calcitriol and the enzyme renin [1].
There are many common variations in the anatomic structure of the kidney. Some variations which are identifiable include: double collecting system, where the renal sinus is divided by a hypertrophied column of Bertin. Horseshoe Kidney, where the left and right kidneys are connected to each other usually at the lower pole and Horseshoe Kidney is the most common fusion abnormalities in the kidney and occurs in 1 in 400 live births, with the male: female ratio of 2:1 [2].Congenital anomalies of the kidneys include a group of so-called fusion anomalies, in which both kidneys are fused together in early embryonic life. Its varied formation in the embryological stages may be a result of tetrogenic factors. Fusion anomalies of the kidneys can generally be placed into 2 categories: horseshoe kidney and its variants, and crossed fused ectopia [3].
One case of anatomical variations identified is the inferior poles of the kidney being joined at their inferior poles inferiorly. The hila reportedly could be seen as expanded and lacking a definite shape. The fusion was located just below the IMA inferior mesenteric artery. In more than 90% of cases, fusion occurs along the lower pole [4]. Horseshoe kidney exhibit many variations in origin, number and size or renal arteries and veins. This feature essentially makes it challenging for surgical transplantation. It is frequently associated with both genitourinary and non-genitourinary malformations, and is also seen as part of a number of syndromes [5]. The most common symptoms that are present are secondary to Ureteropelvic junction (UJP), obstruction, and renal stones [6]. Although horseshoe kidney is not a fatal condition and does occurs as a single entity, they are however prone to a number of complications and other congenital anomalies which can lead to clinical presentation. Different complications can arise from Horseshoe kidney including hydronephrosis and partial duplex system. A duplicated collecting system (also known as duplex collecting systems) is a complication of single or duplicate ureters, arteries and veins. It can also be defined as renal units containing two pyelocaliceal systems that are associated with a single ureter or with double ureters [7]. It is a rare case of duplex renal vessels and superior collecting systems which join at the inferior poles of the kidneys. The prevalence of Partial duplication is 0.6%, while complete duplication of ureters occurs in 0.2% of live births.
Different forms of horseshoe anomalies that have been reported in which a particular case showed a bilateral duplex system in an asymmetrical horseshoe kidney or an L shaped fusion. The