One of the more hotly debated topics over the years is whether or not you can expand your rib cage area. Of course everyone's ribcage expands to some point, but then ceases to grow. The debate is whether or not the rib cage can be expanded beyond this point.
Old School Secret
Some people claim it can happen, and in fact the old 20 rep squat approach often included a set or so of dumbbell or barbell pullovers to do just that. And many trainees who used this training combo (squats and pullovers) noted that their chest size did increase after some time on the routine. And no less than an authority as Arnold Schwarzenegger was a big believer in the benefits and effects of breathing pullovers for a massive rib cage.
Not all old school lifters were enamored with rib cage expansion. In fact Vince Gironda recommended avoiding the pullover and any attempt to expand the rib cage because he thought it didn't enhance the V shape and made the chest region look boxy instead of streamlined.
However, the idea of being able to add a few inches to your chest measurement is attractive to many guys. Building up your rib cage gives your pec muscles a higher platform to sit on and in turn a more visible appearance, as well as a bigger ratio over the waist.
The training approach used by the Old School crew was to perform a set of 20 breathing squats, with a significant weight load aboard (breathing squat is when you take a deep breath on descent for each rep).
Immediately after the breathing squats, you grab a dumbbell or barbell and go prone, face up, back on bench, to crank out some pullovers. And these involve heavy breathing action as well. You want to push the lungs and rib cage as far as you can, to push them beyond their normal boundaries.
A couple of sets per each set of breathing squats is best, with minimal rest between the two pullover sets and no rest between the squatting and the first pullover set.