Granted, with regard to the tanna of our mishna, one can say that the cases of tereifot that he taught explicitly in the mishna, he taught, and that any case that he omitted comes under the general statement beginning: This is the principle. But with regard to the tanna of the school of Rabbi Yishmael, who said: Eighteen tereifot, one must ask: And are there no more cases of tereifot? But aren’t there the four cases represented by the mnemonic beit, samekh, gimmel, reish, the first of which is taught in a mishna (76a): An animal whose hind legs were severed from the leg joint and above is a tereifa? The Gemara responds: The tanna of the school of Rabbi Yishmael holds in accordance with the opinion of Rabbi Shimon ben Elazar, who says: The severed leg can be cauterized and the animal will live. Therefore, such a wound does not render the animal a tereifa.

The Gemara objects: But even if one holds that the severed leg can be cauterized and the animal will live, this does not mean that the animal is not a tereifa. According to whom is the question: But aren’t there the cases of beit, samekh, gimmel, reish, stated? It is stated according to the tanna of the school of Rabbi Yishmael, who holds that there are only eighteen tereifot. But the tanna of the school of Rabbi Yishmael maintains that a tereifa can live. If so, the fact that the animal can live if the stump of its severed limb is cauterized is immaterial to whether it is a tereifa. Rather, say that the tanna holds in accordance with the opinion of Rabbi Shimon ben Elazar insofar as he says that an animal with a severed leg is kosher. Yet, he disagrees with the claim that the reason is because the animal can survive.

The Gemara objects: But isn’t there the case of a deficiency in the spine? As we learned in a mishna (Oholot 2:3): How much is considered a deficiency in the spine of a corpse so that it will not be considered a full corpse to impart impurity in a tent? Beit Shammai say: Two missing vertebrae, and Beit Hillel say: One vertebra. And Rav Yehuda says that Shmuel says: Just as Beit Shammai and Beit Hillel disagree with regard to ritual impurity, so too they disagree with regard to a tereifa, i.e., according to Beit Hillel an animal missing only one vertebra is a tereifa. This is not included in the count of Rabbi Yishmael.

The Gemara responds: The omasum or the reticulum that were perforated on their outer walls, which you count as two separate cases, should be counted as one case. Accordingly, one case has been removed from the count of eighteen tereifot and one case has been inserted, i.e., the case of a deficiency in the spine, and there are still only eighteen cases.

The Gemara asks: But isn’t there the case of the tereifa mentioned in the mishna on 54a of an animal whose hide was removed? The Gemara responds: The tanna of the school of Rabbi Yishmael holds in accordance with the opinion of Rabbi Meir, who deems such an animal kosher.

The Gemara asks: But isn’t there also the case of an animal that is a tereifa because of a shriveled lung? The Gemara responds: The mishna states that a perforated gallbladder renders the animal a tereifa; but who teaches this? Rabbi Yosei, son of Rabbi Yehuda, teaches this. Therefore, the tanna removed the gallbladder from the list, since it is only the opinion of an individual, and inserted a shriveled lung.

The Gemara asks: But aren’t there the seven additional halakhot, i.e., cases of tereifot, taught by amora’im? The Gemara enumerates the seven halakhot: As Rav Mattana says: This head of the femur that was completely dislocated renders the animal a tereifa. And Rakhish bar Pappa says in the name of Rav: If the animal was diseased even in one kidney, it is a tereifa. And we learned in a mishna (54a) that if the spleen was removed the animal is kosher, and with regard to this mishna, Rav Avira says in the name of Rava: They taught this only when the spleen was removed; but if it was perforated, the animal is a tereifa.

The Gemara continues: And Rabba bar bar Ḥana says that Shmuel says: If the two organs that must be severed in ritual slaughter [simanim], i.e., the windpipe and the gullet, were mostly detached, the animal is a tereifa. And Rabba bar Rav Sheila says that Rav Mattana says that Shmuel says: If a rib was torn out from its root, along with half of the attached vertebra, the animal is a tereifa; and a skull that was mostly crushed, even if the membranes are intact, renders the animal a tereifa; and if a majority of the flesh that envelops the majority of the rumen was torn, the animal is a tereifa.

The Gemara responds: There are eight cases of perforated organs mentioned in the mishna that render an animal a tereifa. The tanna of the school of Rabbi Yishmael counts them all as one case. Accordingly, he removed seven cases from the count of eighteen and inserted these seven halakhot.

The Gemara challenges: If so, since there are also two cases of cut organs in the mishna, the spinal cord and the windpipe, let the tanna count them as one. The count of tereifot then falls one short of eighteen. And furthermore, if all the cases of perforated organs are counted as one, then one cannot insert the case taught by Rav Avira in the name of Rava, i.e., that of a perforated spleen, since it is also a case of a perforated organ. If so, the count falls two short of eighteen.