With a needle and thread you can make button down shirts wearable!

The buttons and button holes on a standard shirt can spread open when you move, right in that area:

Solution?  Close up that area!  There are a variety of ways to do that.  Generally what I see is a snap or hook and eye added halfway between each button.

My preference is to try on the shirt, and find where it gaps- then sew that portion of the shirt closed.  Turning the shirt inside out, you can take a needle and thread and very lightly do a whip stitch on the overlap.  It doesn’t need to be tightly or evenly sewn to work.   I only sew the gapping part closed, leaving the rest of the buttons and button holes to behave normally.  Tada!  Magically a button down shirt that fits across the bust line, worry free!

Whip stitch:

http://www.google.com/search?q=whip+stitch&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

Added bonus?  Your shirt will be easier to iron over that area.