VUJ is synonymous with "ureterovesicular junction" (UVJ). It is nearly synonymous with "ureteral orifice" (UO), although depending on the context, the VUJ could include a small amount of the distal most ureter, whereas the UO is limited to the opening from the ureter into the bladder only.
The VUJ inserts at an angle into the bladder trigone. This configuration closes off the ureteral orifice as the bladder expands. If there is alteration of the angle, this may lead to vesicoureteral reflux (VUR).
The Chwalla membrane is a thin membrane between the ureteric bud and urogenital sinus. The Chwalla membrane has to dissolve/rupture during embryonic development to form a patent VUJ. If this membrane does not rupture, it results in a ureterocele.
- 1. Alcaraz A, Vinaixa F, Tejedo-Mateu A, Forés MM, Gotzens V, Mestres CA, Oliveira J, Carretero P. Obstruction and recanalization of the ureter during embryonic development. (1991) The Journal of urology. 145 (2): 410-6. Pubmed