Back ribs a.k.a. loin back ribs. Connected to the backbone, nestled beneath the loin muscle, are the most tender and leanest ribs. A typical full slab has 11 to 13 bones. The slab is tapered at one end, with the shortest bones only about 3″ and the longest about 6″. They are usually curved like a hockey stick at the end where they meet the spine. Depending on how the butcher removes the loin meat that is on the humped side of the bones.