I will spare you a pig diagram, because you and pigs both deserve better. But here's the deal. Rib chops, like all pork chops, are cut from the loin, which basically runs down the pig's back between shoulder and tush. (I say tush because butt is confusing on a pig — more on that never.) It's a good, tender cut, once reserved for the wealthy, and is where the expression "high on the hog" came from. The loin gets cut into chops if we're having chops. Rib chops come from behind the shoulder and can be pretty varied depending on whether they're cut from closer to the shoulder or the tuchus. (Technical term.) Regardless, they take well to brining and searing, and they should cook nice and evenly, so they're a good choice for this dish.