A morphometric study of the pelvi-ureteric junction and review of the pathogenesis of upper ureteric obstruction.

A morphometric analysis has been made of the normal human pelvi-ureteric junction and upper ureter. There was found to be no anatomically definable pelvi-ureteric junction. Muscle bundles of renal pelvis and upper ureter run a spiral course and do not form clear-cut layers. There is a great normal variation of thickness of the renal pelvic and ureteric muscularis, as well as of the total thickness of these structures. Smaller, but sometimes still large differences, are seen between right and left pelvi-ureteric specimens of individual patients. Suggested normal ranges of thickness are: (1) Renal pelvis: total thickness 340-1300 micrometers, muscularis 270-1100 micrometer. (2) Upper ureter: total thickness 450-1000 micrometer, muscularis 240-790 micrometer. No neurones are present in the renal pelvis or upper ureter. The possible etiologies of pelvi-ureteric obstruction are discussed.