i think its the 'type of rib' that you buy. i found a reference on line to "soft bone" ribs
Pork carcasses are typically butchered into several main cuts or portions including country-style ribs, back ribs and spare ribs. Pork spare ribs are further divided and sold as either St. Louis style spare ribs or breast bone spare ribs. St. Louis style spare ribs generally comprise the upper part of a rib separated from the breast bone or brisket bone by costal cartilage. Because of the generally meatiness and minimal fat associated with the St. Louis style ribs, there is a greater demand for St. Louis style ribs which are consequently more profitable for food providers.
In contrast, the breast bone portion of the spare ribs removed from the St. Louis style spare ribs includes the sternum or hard bone, costal cartilage, soft bones, skirt meat, false lean hanging fat and other tissue. Typically, the breast bone portion is trimmed to remove the skirt meat containing small meaty pieces, otherwise known as rib tips. The remaining breast bone portion contains the hard bone, a large percentage of fat and the soft bones which infiltrate most of the breast bone portion. The soft bones, otherwise known as cartilage bones, are separated from one another by pork meat and tunnel fat. Consequently, trimming away any remaining meat from between the soft bones is difficult. As a result, the remaining breast bone portion is typically viewed as an off-fall product, is not considered desirable by consumers or food producers, and is typically sold at a much lower price.
but why not ask at your local resturant?