Some observations and theories on the wide ureter and hydronephrosis.

A simple but effective classification of the wide ureter is proposed. It separates ureters into two major groups of refluxing and non-refluxing, but emphasises that not all non-refluxing ureters are obstructed. An analysis is made of normal and abnormal ureteric peristalsis and the part it plays in conducting a bolus through the pelviureteric and ureterovesical junctions. A theory is advanced to explain the poor emptying of the wide ureter and the abnormal pelviureteric junction. It is based on the inability of the circular and longitudinal muscles to form a bolus and it explains how the unopposed and inadvertent contraction of the circular muscle grips the orifice in each situation to aggravate the poor emptying.