Originating in St. Louis, Missouri, a leader in the meat-packing industry in the early 20th century, St. Louis Style Ribs begin as pork spareribs. When the breastbone is cut off, the ribs take on a uniformly rectangular shape. St. Louis Style Ribs are not always easy to find pre-cut. And when you do find them, they can be a little pricey. Learning how to trim them yourself will save you time and money. For this cut, you’ll remove the sections of the spare rib that generally cause ribs to cook unevenly.