An anatomical exploration into the variable patterns of the venous vasculature of the human kidney.
In clinical anatomy, the renal venous system is relatively understudied compared to the arterial system. This investigation aims to clarify and update the variable patterns of the renal venous vasculature using cadaveric human (adult and foetal) and Chacma baboon (Papio ursinus) kidneys and to reflect on its clinical application, particularly in surgery and radiology. The study employed gross anatomical dissection and detailed morphometric and statistical analyses on resin cast and plastinated kidneys harvested from 211 adult, 20 foetal and 10 baboon cadavers. Radiological techniques were used to study intrarenal flow, renal veins and collateral pathways and renal vein valves. The gross anatomical description of the renal veins and its relations were confirmed and updated. Additional renal veins were observed much more frequently on the right side (31 %) than previously documented (15.4%). A practical classification system for the renal veins based on the number of primary tributaries, additional renal veins and anomalies is proposed. Detailed morphometric analyses of the various parameters of the renal veins corroborated and augmented previous anatomical studies. Contrary to standard anatomical textbooks, it was noted that the left renal vein is 2.5 times the length of its counterpart and that there are variable levels of entry of the renal veins into the IVC. Justification for the distal segment of the left renal vein to be termed the surgical trunk, and the proximal segment to be the homologue of the right renal vein is presented. Radiological investigations demonstrated a non-segmental and non-lobar intrarenal venous architecture, an absence of renal vein valves and extensive venous collaterals centering on the left renal vein. These collateral channels, present in the foetus, and persisting in the adult, may be operative and of clinical significance in pathological states. No sex differences and no race differences of note were recorded in this study. The Chacma baboon displayed similar intra-renal venous anatomy. The applied clinical anatomy of these findings with particular regard to renal surgery and uro-radiology is emphasised.