**1. Introduction**

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Suppl):2072-8.

108 Recent Advances in the Field of Urinary Tract Infections

The detailed anatomy and the nature of the anti-reflux mechanism of the human vesicoure‐ teric junction (VUJ) are still unknown and controversial. VUJ is traditionally thought to be a passive valve; however, recently there is increasing evidence to support the theory of a func‐ tional active neuro-muscular sphincter present at the VUJ. In this chapter, we sought to de‐ scribe different forms of ureteric jet that can be visualized in both grey-scale and color Doppler ultrasound. We are going to summarize the results of a number of original studies based on large number of human subjects. From the observations of these studies, we pro‐ pose the dual mode of action and an active functional sphincter at the VUJ.
