The beef carcass has 13 pairs of ribs, but not all of the ribs are included in the rib primal cut. The first 5 ribs are part of the chuck cut in the front of the animal. The 13th rib is part of the loin. The rib primal contains ribs 6 through 12.
A short rib refers to a small piece that has been trimmed from the main portion of a rib when the rib cage is trimmed into smaller cuts. Short ribs are cut from the chuck and plate primals and back ribs are from the rib primal. Short ribs cut parallel to the bone are known as English style short ribs. They may include a bit of the bone or may be sold boneless. Short ribs that are cut across the rib bones are known as flanken.