I’ve wanted to say this in context forever.
PECTUS EXCAVATUM!
My friend who I lift with has that, he presses harder than I do but my chest seems twice the size of his (I actually even weigh around 10lb less, too…) I know its probably not what you’re talking about, but its like he has a valley where his sternum is. When he benches I could probably pour 6oz of water in there and it’ll stay.