Contribution to the trigone musculature in the case of ureteral duplication

A case of bilateral ureteral duplication with asymmetric orifices is reported. This case served as an example for the evaluation of the arrangement of the trigone musculature in such patients. The muscle fibers radiating from the craniomedial of the 2 orifices constitute the upper portion of the trigonum musculature (Mercier's bar), while the fibers radiating from the caudolateral orifice constitute the lower portions (Bell's muscles). Never did a "muscle fiber fan" of 1 orifice contribute to the upper and lower areas. The farther from the median an orifice is situated, the longer and, possibly, the weaker are its related muscle fibers.