Structure of the Pelvic Ureter in an Adult Kenyan Population

Alterations in histomorphological features of the pelvic ureter such as muscle fiber orientation have been implicated in the etiology of vesicoureteric reflux. Consequently, anatomical sex differences in the histomorphology of the pelvic ureter may explain the female predisposition to this disease. Reports of these differences are, however, scarce. Twelve adult pelvic ureters (6 male and 6 female), harvested during autopsy were used for histomorphology. Five-millimeter thin sections were taken from juxtavesical, mid and distal intravesical segments of the ureter. These were fixed in formal saline solution and processed routinely for paraffin embedding. Seven-micrometer sections were stained with Masson’s Trichrome stain to demonstrate orientation of smooth muscle cells and collagen fibers. In all sections, the ureter displayed a mucosa, muscularis and adventitia. In males, the muscularis of juxtavesical ureter displayed three layers namely an inner longitudinal, intermediate circular and an outer longitudinal. In females only two layers namely an inner longitudinal and outer circular were observed. In the mid intravesical segment, the muscularis in males displayed two layers: an inner longitudinal and outer circular layer while in females only the longitudinal layer was present. The structure of the pelvic ureter therefore displayed sex differences. In males, the muscularis in the juxtavesical and mid intravesical segments possessed additional longitudinal and circular layers respectively. These structural differences could partially explain the higher predisposition to vesicoureteric reflux in females