In the U.S., the Porterhouse/T-Bone make up the Short Loin, which is located between the Rib (at the front) and the Sirloin (at the rear). The T-Bone is separated from the Rib by the width of a knife blade, and consists of the New York/Top Loin/Strip/Club/Delmonico steak if it were boned out. Further back, the T-Bone becomes a Porterhouse when the Tenderloin appears, which if boned out consists of the NY + Filet Mignon (aka Tenderloin). There are 3 or 4 Porterhouse steaks on the Short Loin, depending on the thickness. The cut of the Sirloin next to the Porterhouse is called the Pin Bone Sirloin if it hasn't been boned out. The best way to buy steak and get the best bang for the buck, is to disregard the label description, and become familiar with what the cut actually looks like. An example is the cut called "Prime" Rib, where one end is a continuation of the Chuck, and the other becomes T-Bone.