I have collected some info and edited it to the best of my abilty to clarify the types of Pork Ribs. If someone has a different idea please chime in. When I had the restaruant I only used Baby Backs and they were graded at 1 /34 pound and down. Overview. Pigs have 14 ribs. They are attached to the spine and are usually divied up into four popular cuts: Baby Back Ribs, Spare Ribs, St.Louis style, and Country Style ribs. Starting at the top are the baby backs, closest to the backbone, nestled beneath the loin muscle. They are curved, round, close together, and most of the meat is on top of the bones, cut from the loin muscle. As you move further from the spine, the bones get larger, flatter, straighter, and wider apart with more meat between them. There is more fat marbling in the meat as you go further from the spine and closer to the belly. The front ribs are connected to the breast bone with a number of small bones and cartilage known as the rib tips. Spare Ribs , 3 1/2 & down, 4 & over, etc. This is butcher talk for the weight of a slab of spareribs. A "3 1/2 & down" weighs 3.5 pounds or less untrimmed, with the tips attached. Most chefs prefer theirs 3 1/2 and down, from younger hogs. Back ribs (a.k.a. back ribs, a.k.a. baby backs, a.k.a. loin back ribs, a.k.a. loin ribs, a.k.a. Canadian back ribs). They are graded by weight the lighter the weight the smaller the pig . Back ribs are attached to the spine on one end and to the spare ribs on the other. They contain 8-14 bones per slab, and are less fatty than spares. A typical full slab has 11-13 bones. The slab is tapered at one end, with the shortest bones only about 3" and the longest about 6". Because they weigh less than spare ribs, they cook faster. They are usually curved like a hockey stick at the end where they meet the spine, (called the chine side). Depending on how the butcher removes the loin meat that is on the convex side of the baby backs, some can have up to 1/2" of delicate, lean loin meat on the top. Baby spare ribs. These are not the same as Baby Back Ribs. Nor do they necessarily come from young tender pigs. These are Spare Ribs made smaller by removing the Rib Tips. These are more properly called St. Louis Ribs but some butchers call them baby spare ribs to capitalize on the popularity of baby back ribs. Country-style ribs. Country-style ribs are not really ribs. They are cut from the front end of the loin near the shoulder (the shoulder is also known as the "butt" for some strange reason) and a tray in the grocery store can contain contain few, if any, ribs. In fact, if there are bones, they are often part of the shoulder blade. Country-style ribs are more like chops, more meaty and less fatty tham real ribs, and should be treated like chops, not ribs. There is no membrane on Country style ribs. Membrane.Spares, St.Louis, and back ribs. Each slab has a meat side and a bone side. The meat side is convex (curving towards you), and the bone side is concave (curving away from you). The bone side has a membrane called the pleura covering it. It can be leathery and almost unchewable when cooked, and it can prevent flavorings and smoke from penetrating. Many butchers remove the skin. If the membrane has not been removed when you bring home a slab, you should remove it yourself. Spare ribs (a.k.a. spares, a.k.a. side ribs). Spares come from further down the side than baby back ribs and there is more bone than meat in a slab of them. USDA says a slab must have at least 11 bones. They are also straighter and flatter than baby backs. The bones, connective tissue, and the fat make them very flavorful. Look at a slab of spare ribs and you will notice that along one edge the ends of bones are showing and you can see marrow This is where they were cut from the baby backs. The other end, with no bones sticking out, is a gristly flap from the sternum to the belly side, called Rib Tips. Spares are a little less expensive than baby back ribs because they have more bone. The price difference is also because demand for baby backs has grown significantly. St. Louis cut ribs (a.k.a. SLC a.k.a. barbecue cut, a.k.a. Kansas City cut). Lop the rib tips and the flap meat off a slab of Spare Ribs, and what remains is a flat rectangular slab called the St. Louis cut. Many experts like the taste of the St. Louis cut even better than the more expensive Baby Back Ribs because there is more meat between the bones, and it is better marbled. You can also trim your own if you want. I hope this helps dispel the differensces in pork ribs. Maybe some of our butchers can chime in also as things are labeled differently by region.