A contribution to the history of renal structure knowledge (from Galen to Malpighi).

This work documents the progressive gain in knowledge on renal anatomy acquired by anatomists from Galen to Malpighi. Galen, with albeit his rather imaginative explanations, was the first anatomist to recognize the urine producing function of the kidney. His influence was felt up to the Middle Ages; his followers imagined the presence of two cavities within the kidney that were separated by a porous membrane that they called the "colatorium" which was capable of filtering the urine from the blood. It was only later that Berengario da Carpi, divorcing himself from Galenic dogmatism, finally dismissed the presence of the colatorium. He described the renal papillae and gave the first elementary model of renal vascularization. Further important progress was due to the studies of Falloppius and Eustachius who brought contemporary understanding of renal structure to the limit of what could be seen with the unaided eye. They distinguished the difference between the unilobar canine kidney and the human multilobar organ, they also described the minor and major calyces and, furthermore, guessed at the canalicular structure of its parenchyma. Highmore was then responsible for the description of the archiform vessels which he hypothesized as an arterio-venous anastomotic net between the renal cortex and medulla. With the invention of the microscope, new doors opened for the study of renal structure. Bellini proved the canalicular organization of the parenchyma and, moreover, described the interlobular vessels. Malpighi then described the glomerulus and its relation to the intrarenal excretory ducts. The basis had now been laid for the beginning of modern nephrology.