Can you guys explain how the PCV lines are routed down into the crankcase?

My crankcase is getting pressurized (it's a boosted car), and I'm trying to understand if there is any difference internally on how the two different (inlet and outlet) PCV lines route down in the motor. I know that one is on the vacuum side (after the TB) on the outside, but is there really any difference internally.

I know that my PCV outlet is blocked under boost (I have a check valve to keep it from creating pressure in the crankcase), but I'm trying to figure out why pressure is not going out the inlet side in this situation.

I probably have a piston problem causing the excessive pressure in the crankcase, but I want to get my facts straight about how the PCV works before I start running other tests.