Help with Pec to Back Link Exercises

[workmeout]

Does anyone know what the muscle or muscle group is below the armpit that connects the back to the pecs in the front.

I'm new to lifting and I'm doing a lot of flat back flies. It's doing wonders for pecs but that area under the arms remains stubbornly flabby.

Can anyone explain what that muscle is and suggest some exercise to tone it up?

Thanks.

[swanso5]

i'm assuming the lat dorsi and / or teres major/minor for memory...which ever it is you need to start doing bent chin ups variations, pulldown variations and even some serratus work wouldn't hurt such as anything where you hold the wt over your head (military, overhad side bends etc)...and diet definately