Can I just ask where this is going? It sounds like you actually think the Qur'an has made a meaningful discovery by saying the semen comes from between the front and the back of the body...
I'm not saying that, I'm just saying it is easy to define the position of something as you seem to be confused over it *shrugs*
and you believe that thinking of the body as being divisable into 3 layers is a meaningful way of talking about the body,I don't think it's meaningful as it's too simplistic but if you want to apply that way of thinking then I don't see where the confusion lies for you. It's easy to say where something is relative to the middle (subjectively of course).
This 'debate' is crossing over into semantics which I hate, lets end it shall we as it's going nowhere and making us both confused