FETAL AND POSTNATAL DEVELOPMENT OF THE INTRARENAL ARTERIAL PATTERN IN MAN. A MICRO-ANGIOGRAPHIC AND HISTOLOGIC STUDY.

Abstract

SUMMARYThe development of the intrarenal arterial pattern in man has been studied by parallel micro‐angiographic and histologic examinations on 104 kidneys obtained from 64 autopsy subjects, ranging in age from the fourth fetal month to the twentieth year of life. Various stages of development of the glomerular capillary tuft were noted, but the most primitive ones were no longer observed after the first week of life.In the fourth fetal month well‐developed arteriole‐glomerular units were found in the juxtamedullary zone and the pelvic connective tissue. These subsequently gave off postglomerular vessels to the medulla. From the end of the fourth fetal month a cortico‐medullary vascular pattern was present with arteriolae rectae leading to the medulla and a cortical arrangement of the glomeruli. Postglomerular vessels in the cortex did not appear until after the eighth fetal month, andup to that time the lobar circulation is therefore probably medullary.Glomeruli in the pelvic and periarcuate connective tissue began to degenerate during the seventh fetal month, with the formation of so‐called arteriolae rectae verae to the medulla through canalization of the glomerular scars. These scars were gradually incorporated into the connective tissue and became istologically unidentifiable.seventh year of life juxtamedullary glomeruli outside the periarcuate connective tissue began to degenerate with the formation of arteriolae rectae verae. Vessels to the renal pelvis were given off by pelvic arteriole‐glomerular units.ninth fetal month there was evidence of congenital glomeruloscierosis ‐that is, sclerosis of scattered cortical glomeruli with atrophy of the whole arteriole‐glomerular unit.