Pig kidney: anatomical relationships between the renal venous arrangement and the kidney collecting system.

PURPOSE We present a systematic study of the anatomical relationship between the intrarenal veins and the kidney collecting system in pigs. MATERIALS AND METHODS The intrarenal anatomy (collecting system and veins) was studied in 61, 3-dimensional endocasts of the kidney collecting system together with the intrarenal veins. RESULTS There are free anastomoses between the intrarenal veins. The interlobar veins unite to produce large venous trunks, which form the renal vein. In our study we observed 2 trunks (cranial and caudal) in 54 of the 61 cases (88.53%) and 3 trunks (cranial, middle and caudal) in 7 (11.47%). Only the ventral surfaces of the cranial and caudal poles were drained by large veins, while the dorsal surfaces emptied by anastomoses into the ventral interlobar veins. There were large veins in a close relationship to the ventral surface (90.16%) and to the dorsal surface (3.28%) of the ureteropelvic junction. In 33 of the 61 cases (54.10%) there was 1 or 2 small dorsal veins. CONCLUSIONS Although some results of intrarenal venous arrangement in pigs could not be completely transposed to humans, many similarities of pig and human kidneys support its use as the best animal model for urological procedures.