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Applied anatomy
Kidney
The kidneys are retroperitoneal organs lying high in the abdomen on either side of the vertebral column. The upper poles are more medial and posterior than the lower poles, making the longitudinal axis oblique. In addition, the medial aspect of each kidney is rotated anteriorly at 30°. These details are important when planning percutaneous renal access (Figure S82.1).
The perirenal space contains the adrenal gland, kidney, ureter and renal vessels. The perirenal space is enclosed by a condensed, membranous layer of fascia (of Gerota) as a barrier to the spread of malignancy and fluid collections.
The renal vessels enter the kidney via a medial fissure at the renal hilum and usually consist of a single artery and vein. The renal vein is usually anterior to the artery. In the hilum, the artery divides into five segmental end arteries. Brödel’s line (or area) is an avascular plane between regions supplied by the posterior and anterior segmental arteries (Figure S82.2). Incision or puncture through this area avoids injury to the segmental and interlobar arteries.
Ureter
The ureter exits the renal pelvis and crosses the pelvic brim at the bifurcation of the common iliac artery. It then runs along the lateral wall of the pelvis to enter the urinary bladder. There are three persistent constrictions that are potential sites for obstruction by stones. These constrictions occur at the pelviureteric junction (PUJ), at the bifurcation of the iliac vessels and where the ureter enters the bladder. In females, the close proximity of the ureter to the uterine vessels and vaginal vault is the cause of injury during gynaecological procedures (Figure S82.3).
Applied anatomy
- Renal axis of the kidney is oblique – the upper poles are more medial and posterior than the lower poles and the medial aspect is rotated anteriorly
- The Gerota fascia is open only inferiorly
- From anterior to posterior, the renal hilar structures are:
- V – renal vein
- A – renal artery
- P – renal pelvis
- A – posterior segmental artery
- (mnemonic VAPA)
- Common areas of obstruction by ureteric calculi – ureteric constrictions at the PUJ, at the region of the iliac vessels crossing and the ureterovesical junction
- Course of the lower ureter in the pelvis should be well understood, especially in females, in order to prevent ureteric injures during pelvic surgeries
- Preserving periureteral adventitial tissues while mobilising ureter will prevent ureteral ischaemia
Congenital Anomalies of the Kidneys and Ureters
Embryology
The development of mature kidney and ureter is closely interlinked. The ureteric bud develops as an outpouching of the mesonephric duct or the Wolffian duct, which joins the caudal end of nephrogenic cord to induce formation of the metanephric blastema. This develops later into mature kidney. Once joined, the ureteric bud and the metanephros migrate upwards from the sacral position to the adult lumbar position. During this cephalad migration, the kidney rotates from its ventral position by almost 90°, such that the ureter becomes most posterior and medial in orientation. During its ascent, the kidney receives its blood supply from various aortic segments and its final supply from the lumbar region of the aorta.
Dimitrie D Gerota, 1867–1939, Romanian anatomist, physician and radiologist.
Paul Heinrich Max Brödel, 1870–1941, American–German medical artist, Johns Hopkins University School of Medicine, Baltimore, MD, USA, a renowned anatomist.
Kaspar Friedrich Wolff, 1733–1794, Professor of Anatomy and Physiology, St Petersburg, Russia, described the mesonephric duct and body in 1759.