[The pelvicaliceal system in the sonogram--distinction between physiological and pathological dilatation].

Dilatation of the pelvicalyceal system was documented in volunteers with healthy kidneys in whom renal excretation was increased by means of a variety of methods. As a rule, the proximal ureter is not visualised. In mild or moderate urinary obstruction, however, the ureter is almost always visible, and stasis is mostly unilateral.