Another Median Lobe Question

Hello group: I've heard that an enlargement of the median lobe of the
prostate acts like stopper, and shuts off urine flow from the bladder.
I can't visualize this in my head, and was wondering if someone could
post a simplified drawing of what this actually looks like. Also would
this prevent complete emptying of the bladder each time, or could it be
a random event? Thanks, Corky

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