I' ll take a minute or two to research good field dressing books for you, but I' ll answer your first question first. Between the rib cage and the hams of any animal, along the spine, you have two cuts of meat - the tenderloins and the backstrap. The backstrap is along the outside, the tenderloins along the inside. If your butcher gives you several packages (and a large quantity) of ' tenderloin,' then yes, your tenderloin and your backstrap is being packaged together.