Hullin 52: Dislocations

A majority of broken ribs -- seems to be a treyfa. But what is the way in which they were broken? Does having been attached to the vertabrae make the process that much more challenging? If the ribs are dislocated and the spine is not damaged. Also, an animal that is clawed by a wolf (or a predator of that size or larger) will render the victim animal a treyfa (and predator birds from a "netz." But what about a small animal, like a cat?