Senora Featherbottom is right, usually this edge is overcooked and it is the VERY BEST few bites on the ribeye or prime rib. If you've had prime rib or ribeye, you know what we're talking about, that one edge that is super tender and flavorful.
Well, that's what a cap steak is made of. The butcher removes all the spinalis and forms them into their own steak, usually tied into a circle with butcher's twine. They may look like a filet mignon at first glance since they're almost always close to perfectly round and thick, but they're 1000x better (not too difficult to be better than a filet mignon IMO, that's why you see 'bacon wrapped filet mignon' advertised, because by themselves they don't taste like much. The filet mignon has a powerful marketing lobby)
For our holidays, my family requests cap steaks instead of anything else. Baked in the oven and then reverse seared in a cast iron pan, the results are nothing short of amazing.
Imagine, EVERY bite is a spinalis bite. Heaven on earth.