Traditionally it is called the vesicoureteric junction, however some anatomists, radiologists and other clinicians, insist that ureterovesicular junction is more correct. This stems from the idea that junctions in anatomy generally use the more proximal component of the connecting parts as the first part of the word, and the more distal part, as the second part of the word, e.g. metacarpophalangeal, not phalangeometacarpal, and ileocecal valve, not caecoileal.
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 vesicoureteric junction 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.