How can I use nasal sprays to hit the deep sinus cavities (ie. sphenoid)

My infections are usually in the deeper, further back sinus cavities (sphenoid) and I'm wondering if these nasal sprays will hit all the way back there, or if there is a certain way I have to lean while doing the spray in order to hit the cavities.

I'm going to be starting an anti-fungal nasal spray because I'm now convinced that this is fungal, after years of suffering and zero quality of life (ie. sinus infection that has not gone away in over 5 years).  I just want to make sure I'm hitting all 4 sinus cavities and how to make sure the medicine gets up there.

Thank you!!!

[friggy]

Nasal sprays or saline irrigation won't reach the sphenoids, due to gravity.

This does

http://www.medhelp.org/user_journals/show/2322

The Flip-Turn Sinus Flush is mildly risky, because you have to bend over to do it, preferably in a shower, but you can also do it outside on soft ground, or you can kneel down and lean over a bathtub, or perhaps a plastic basin or tub, with the shower running for steam.