Retrograde Urethrogram- (RUG) stick a catheter into the very end of the penis, inflate a small balloon to keep the x-ray contrast (dye) from running out, inject contrast, see if the urethra (going from bladder through the penis to outside) is intact, not torn, not gouged into, not blocked.

Retrograde means against the normal flow of things. (Antegrade would be _with_ the natural flow).

The urethra may also be visualized during a voiding cystogram- fill the bladder by gravity with contrast, then the patient pees it out- but sometimes they can't pee, and it takes a lot longer. TThe VCUG is for looking for reflux of urine back to the kidneys like it's not supposed to go (and carrying bacteria with it, in the case of a child who is prone to UTIs) and a plain cystogram looks for bladder injury or abnormality.