When renal echograms are made, the central renal pyeloealyceal complex (CRPC) is seen as a strongly echogenic oval confluence surrounded by echo-poor renal parenchyma. Fragmentation of the CRPC is abnormal, and this fragmentation is widely known in association with urinary obstruction. But, there are a variety of nonobstructive causes for dispersion of the CRPC: renal duplication, postobstructive atrophy, chronic pyelonephritis, renal sinus lipomatosis, nephrocalcinosis, and renal cystic disease. Patterns of CRPC fragmentation may be correlated with renal parenchymal status to determine the cause of abnormal renal echograms. © 1979.