Tosefta do Chullin 4:9

[If] it broke most of its ribs, it is disqualified (Hul. 3:3). And how many are "most of its ribs"? Eleven ribs on one side of the spine, or eleven ribs on the other side of the spine. [If] it broke twelve [ribs] from both sides (i.e., cumulatively), it is disqualified. [If] there remained eleven [intact ribs] from both sides (i.e., cumulatively), it is valid. [If] it its hind leg is cut off from the knee joint and below, it is valid; from the knee joint and above, it is disqualified (Hul. 4:6). [If] a bone was broken and the junction of the sinews was interrupted, it is invalid. Rabbi Shimon ben Elazar deems it valid because [the leg] can be cauterized and it will live (Hul. 42b:1). [If] a person caused its [lungs] to be shriveled, it is disqualified. Rabi Shimon ben Elazar says, [this rule applies if the shriveling is] caused by any living creature. Rabbi Meir validates a large animal [with a shriveled lung], but the Sages disqualify it. Said Rabbi Shimon ben Elazar, Rabbi Meir did not disagree about whether a large animal [with a shriveled lung] is disqualified. Yehudah ben Yeshaiah the spicer testified before Rabbi Akiva that it was said in the name Rabbi Tarfon about the large animal that is disqualified. What is the large animal [that is disqualified]? One that has been stripped of its hide and there does not remain enough [skin] to allow a scab to form. But if there remains enough [skin] to allow a scab to form, everyone agrees that it is valid. And how much is enough [skin] to allow a scab to form? Rabban Shimon ben Gamaliel says, up to [the size of] an Italian issar (a unit of money, see Hul. 3:2) from the chamber [?] (בית חללה), but not from the other limbs.