[Obstructions of the lower ureteral segment caused by vascular anomalies (author's transl)].

On four cases we show the clinical symptomatology of the lower ureteral segment by restricting and aberrant vessels. At the same time we pay attention to the right vena ovarica syndrome as an etiological factor of pyelonephritis of pregnancy and to the other vascular anomalies, which cause unilateral ureteral obstructions. Therapy of choice is an operation.