Ribs can be dislocated just like joints, when it happenend to a guy in jiujitsu the doc told him get two chairs set em up like a dip station. No do dips or take your legs off the ground but strech out and if dislocated is should slide back in. Ribs work like joints I forget what sensai said but something like joints have 20 or 4 release points and 5 pounds of pressure right angle could dislocate one.