Inference: "And similarly regarding a Tereifah" refers to both (a spine and skull).

Question #1: Why did Beis Hillel say "in order that one will take from a live person, and he will die? Also according to Beis Shamai, he dies if their Shi'ur is removed!

Question #2: What is the Chidush or Rav Yehudah, who said "the same applies to a Tereifah" regarding a skull, since he dies due to this?

Answer: It is more common to die through removal of a small amount, than if [a small amount is lacking] due to corrosion or illness.

Question: In Chulin (42b), it asks [that there are other Tereifos]! "There are [four, for which the Siman is] Basgar, and there are the seven teachings", and the Samech (of Basgar) stands for ChiSaron of the spine. Why don't we ask also from the skull?

Answer: Chisaron of the skull is Tereifah because ultimately, the membrane around the brain will break, and this is among the 18 Tereifos [of the Mishnah].

However, the spine is not [Tereifah] because the spinal cord will snap, for we discuss [Chisaron] even below where it branches out, and thereת snapping is not Tereifah.

Comment - Implied question: Many people, much was removed from the bone of the skull, and the membrane is not pierced, and they lived (more than a year)!

Answer: We must say that Chisaron of the skull [is Tereifah, only] with [Chisaron] of the upper membrane.

Implied question: There is an opinion that in an animal, in such a case when the upper membrane is punctured, it is Tereifah! (How can that opinion explain why Chisaron of the skull is considered another Tereifah?)

Answer: That is because the lower membrane will ultimately break. However, in a person [the lower membrane] is not destined to break, for it is harder and stronger than in an animal. Therefore, Chisaron of the skull is needed [to make a person Tereifah];

However, according to the opinion that [an animal is not Tereifah] until the lower membrane is punctured, people and animals are the same. If the bone and the [upper] membrane were punctured, the lower [membrane] is destined to break.

Reference: The Yerushalmi says that he tithed on Tana, redeemed (it, in case it is really Ma'aser Sheni) and gave it to poor people.

Implied question: Perhaps he comes to teach that even though [it is not open to Reshus ha'Rabim on either side], Tzuras ha'Pesach is needed!

Answer: It connotes to [the Makshan] that he comes to teach that Tzuras ha'Pesach suffices.

Explanation #1 (Rashi): He discusses when the Rechavah (a Chatzer in back of houses) was breached opposite [its opening to the Mavuy]. If not, what does [Rav Yehudah] teach?

Suggestion: Perhaps he teaches that the Rechavah does not forbid the Mavuy.

Rejection #1: He need not teach this, for the Rechavah does not have residents, like we say below (24b) about the Rechavah in Fum Nahara. The lenient opinion permitted because it has no residents. The Halachah follows Ravina to be lenient!

Comment: Even according to the stringent opinion, we can say that [there], everyone's share in the Rechavah is clarified, and there is concern lest everyone enter his portion, like it says below. (Only in such a case it is considered to have residents.)

Rejection #2: "It does not need anything" connotes that he discusses the Isur of Mefulash (which is sometimes fixed through Lechi, Korah, Tzuras ha'Pesach...), which we discuss.

Conclusion: Therefore, it seems that he discusses when [the Rechavah] was breached opposite [its opening to the Mavuy].

Implied question: Why did he discuss a Rechavah, and not a Chatzer?

Answer: He wanted to teach that nothing is needed even if they were not Me'arev. However, [if it was breached to] a Chatzer, it is forbidden unless they were Me'arev;

This is because he holds that [the wall of the Rechavah to the sides of the opening to the Mavuy, which are] Nir'eh miba'Chutz v'Shavah mibi'Fnim (noticeable from outside the Mavoy, but not from the inside) is not considered to be a Lechi or Pesach. He discusses when the Mavuy ends in the middle of the Rechavah;

It is not considered Mefulash because when one leaves the Mavuy there is room to turn [in the Rechavah] to this direction or that, so people will not come to permit a [Mavuy] Mefulash.

Note: Maharam says that this is all one big Dibur. including the two Diburim of Tosfos on Amud B. There, Tosfos brings another Perush unlike Rashi.

Explanation #1 (cont.): People of the Mavuy do not forbid [the Chatzer], for they have no rights to walk through it. Also Reshus ha'Rabim does not forbid it, for the breach is not more than 10 [Amos], so it is a Pesach;

The Mavuy is forbidden because it is Mefulash. One who stands in the Mavuy sees Reshus ha'Rabim opposite himself, and he does not see that [when he goes from the Mavuy to the Chatzer] there is room to turn to this direction or that.

Inference: Since he discussed when the Chatzer was breached opposite it, this connotes that it is forbidden only when the Chatzer was breached opposite it, for it is like Mefulash;

However, if [the Chatzer] was not breached, even if they were not Me'arev, [even the Mavuy] is permitted, even though the Mavuy was totally breached to the Chatzer, for he holds that [the wall of the Chatzer to the sides of the opening to the Mavuy, which are] Nir'eh miba'Chutz v'Shavah mibi'Fnim is considered to be a Lechi or Pesach;

He establishes our Mishnah (92a), which permits a big [Chatzer that was breached to a small Chatzer] and forbids the small, to be when the walls of the small enter the big. (Nir'eh miba'Chutz... does not apply, for there is no wall to the side of the breach.)

Implied suggestion: Perhaps [the Mavuy] is forbidden because it is Mefulash, and because it was totally breached, and he discusses when they were not Me'arev!

Rejection: If so, he should have discussed a Rechavah, which would connotes that it is forbidden due to Mefulash. Also, it would imply that since he discussed a Rechavah, and not a Chatzer, that there is another Isur regarding a Chatzer, i.e. because they were not Me'arev;

However, now that he discussed a Chatzer, this implies that even the [potential] Isur because they were not Me'arev, which applies to a Chatzer, does not apply. Rather, it is because the Chatzer was breached opposite [where the Mavuy opens to it].

Support: This is why [if Rav Yehudah learned this from Rav,] Rav contradicts himself in two ways, for Rav holds that [Nir'eh miba'Chutz...] is considered a Lechi or Pesach, and he forbids due to Mefulash, and Rav Yehudah does not forbid due to Mefulash, and does not consider Nir'eh miba'Chutz v'Shavah mibi'Fnim to be a Lechi or Pesach.

Explanation #1 (cont.): [Rav Sheshes said] I will explain to you. Here they were Me'arev. I.e. Rav did not forbid due to Mefulash. He mentioned that the Chatzer was breached opposite it only due to the Heter of the Chatzer. Even though many enter through this [side] and leave through this [side], it is permitted;

However, the Mavuy is forbidden even if the Chatzer was not breached opposite it, because it was totally breached to the Chatzer, and they were not Me'arev. He holds that Nir'eh miba'Chutz v'Shavah mibi'Fnim is not considered a Lechi or Pesach.

This is only if it was totally breached. If it was not totally breached, it is permitted, even though they were not Me'arev, since [the Chatzer, i.e. its residents] were not used to [frequenting the Mavuy];

Source: It says that it was breached, which implies that [the Chatzer] was not used to [frequenting the Mavuy, for there was a wall in between].

Implied question: He could have taught a Mavuy open to a Chatzer, that it is forbidden, since [the Chatzer] is used to [frequenting the Mavuy], even if it is not totally open!

Answer #1: Had he taught this, Rav would not teach any Chidush [about the Chatzer, that it is permitted]. Since it is a proper opening, obviously Rabim (traffic) are not Mevatel a Mechitzah!

Answer #2: He could not have discussed open to a Chatzer, for even though [the Chatzer] is used to [frequenting the Mavuy, the Mavuy] is permitted, since the people of the Chatzer have a way to get to Reshus ha'Rabim without the Mavuy;

In such a case, Kofin Al Midas Sedom (we force someone to benefit others, if he will not lose through this. They may not go through the Mavuy, in order that people may carry in the Mavuy), like we say below (49a) about a Chatzer between two Mavo'os.

Note: Maharam says that the previous two Diburim of Tosfos and the coming Dibur are all one big Dibur.

Explanation #1 (cont.): I.e. [the Mavuy] ends in the middle of the Rechavah. Rav Yosef explains Rav Yehudah's teaching, this that he said "nothing is needed";

[Rav Sheshes'] answer "this is when they were Me'arev" was not given in the days of Rav Yosef. Rav Yosef holds that Nir'eh miba'Chutz is considered a Lechi, like we initially thought according to Rav.

Rav Yosef inferred also from Rav Huna (10a), who was Rav's Talmid, that [Nir'eh miba'Chutz] is considered a Lechi.

Question: (On 8a, we say that initially, when we thought that Rav Yehudah cited Shmuel, he argues with Rav about Rav Yosef's teaching, i.e. to forbid when the Mavuy opens to the side of the Rechavah.) It is not appropriate to say that they argue about Rav Yosef's teaching, since they do not discuss the Chidush that Rav Yosef came to teach, i.e. that it is forbidden [when it opens] to a side of the Rechavah!

Answer #1: If not for Rav Yosef's teaching, one might have thought that they argue also about [opening to] a side of the Rechavah, and it would be difficult, how can Shmuel permit [when it opens] to a side of the Rechavah when there are two Re'usos [reasons to forbid]?

One side is open until Reshus ha'Rabim, and also the second side, even though it is not Nir'eh miba'Chutz, Shmuel says that it is not considered a Lechi!

Therefore, it was needed to bring Rav Yosef's teaching, that they argue about when it ends in the middle of the Rechavah, so there are not two Re'usos.

Answer #1 (cont.): Also according to Rav it was difficult. Since he holds that it is considered a Lechi, why does he forbid due to Mefulash? There was reason to say that one depends on the other;

Therefore, he brings Rav Yosef's teaching, that they do not depend on each other. When it ends at the side of the Rechavah, all forbid, even according to the opinion that [Nir'eh miba'Chutz] is considered a Lechi. The reason is because a Lechi helps for a [Mavuy] Mefulash only according to R. Yehudah.

Implied question: Why didn't [Rav Sheshes] answer above that Rav Yehudah discusses when [the Mavuy] finishes in the middle, and Rav discusses when it finishes from the side, or here [Rav forbids when the openings] are opposite each other (it is like Mefulash), and here (Rav Yehudah permits when) they are not?

Answer: He answered the truth, for Rav Sheshes did not answer due to the question, rather, he had a tradition. So we can explain according to Rashi.

Note: Starting from 7a (DH Im), Tosfos has been explaining according to Rashi, including his source from 24b that Rechavah does not have residents. Tosfos now explains the entire Sugya according to the Ri.

Explanation #2 (Ri): The Rechavah here is unlike the Rechavah below (24b), for there we discuss more than Beis Sa'atayim (the area in which one sows two Sa'im of barley, i.e. 5000 square Amos), and it was not Hukaf l'Dirah (surrounded for the sake of residence). It is a Karmelis, and one may carry in it only within four [Amos];

However, the Rechavah here is not so. If it were, it would end in a valley! Rather, it has residents, for we distinguish between whether or not they were Me'arev;

It is no worse than a Churvah (ruin), which it says below (74a) that it is forbidden. All the more so a Rechavah, which has residents more than a Churvah, would be forbidden, if not that we are thinking now that Rav Yehudah holds that Nir'eh miba'Chutz is considered a Lechi;

Explanation #2 (cont.): We are thinking now that since Rav Yehudah does not distinguish in the Heter, this connotes that he permits in every case, even if [the Mavuy] ends at the side of the Rechavah, and the Rechavah was breached opposite [the opening to the Mavuy], even if they were not Me'arev;

Also, since Rav Yehudah discusses when it was breached opposite [the opening], and he needs to teach that it is not Mefulash, if so you are forced to say that he holds that Nir'eh miba'Chutz v'Shavah mibi'Fnim is considered a Lechi;

If it were not considered a Lechi, why is it permitted when it ends at the side of the Rechavah? (Since he needed to teach that it is not Mefulash, it must end at the side.) When it ends in the middle of the Rechavah, obviously it is not Mefulash (since one can turn to either side when leaving the Mavuy)!

If so, (it ends at the side, and we would say that Nir'eh miba'Chutz is not considered a Lechi), there are two Re'usos - one side (of where the Mavuy opens to the Rechavah, i.e. at the side wall of the Rechavah, appears) Mefulash until Reshus ha'Rabim, and the other side, granted, it is Nir'eh miba'Chutz, but it is not considered a Lechi!

Conclusion: Rather, surely it is considered a Lechi, and now there are not two Re'usos, for it is considered a Lechi from one side, like it says below (9b) "we should say Lavud from one side, and it should be permitted!"

Explanation #2 (cont.): [Rav Yehudah] mentioned a Rechavah, because the episode was with a Rechavah, and the same applies to a Chatzer.

Implied question: Rav Yosef said in the name of Rav Yehudah, and [Rav Yosef] establishes it below (8a) when it ends in the middle, but at the side of the Rechavah it is forbidden!

Answer: That was not taught according to the conclusion. (The Gemara says that initially, this is how we established the argument.)

Citation of Gemara: [Rav taught that] the Chatzer is permitted and the Mavuy is forbidden.

Explanation #2 (cont.): Now we are thinking that it is forbidden because it is Mefulash when it ends at the side of the Chatzer and it was breached opposite [the opening], even if they were Me'arev. [We think so,] for if it ended in the middle, it is unreasonable to forbid due to Mefulash;

Source: Since [Rav] said "the Chatzer was breached opposite it" (this connotes that it is due to Mefulash).

Explanation #2 (cont.): [Also,] it is forbidden when they were not Me'arev, even if it ends in the middle, and the Chatzer was not breached [to Reshus ha'Rabim] opposite [the breach to the Mavuy].

Source #1: Since [Rav] mentioned "totally [breached]", this implies that it is forbidden because it was totally breached, i.e. when they were not Me'arev, and [even if the Chatzer] was not breached opposite [the breach to the Mavuy];

If it was breached [opposite], and they were Me'arev, why did he discuss [a Mavuy] totally breached [to the Chatzer]? Even if it was not totally breached, it is like Mefulash, and a Lechi does not help. Tzuras ha'Pesach is required!

Source #2: Also, since [Rav] mentioned a Chatzer, and did not mention a Karfef, which does not have residents, this connotes that he comes to forbid also due to the residents in the Chatzer.

Source #3: Also, if [Rav] forbids only due to Mefulash, he should have said "a Mavuy that was totally breached to the side of a Chatzer." Since he did not say so, this implies that he discusses also when it ends in the middle, and it is forbidden because they were not Me'arev;

He holds that Nir'eh miba'Chutz v'Shavah mibi'Fnim is not considered a Lechi.

Suggestion: Since [Rav] forbids [when the Mavuy was breached] to the side of the Chatzer due to Mefulash, this proves that holds that [Nir'eh miba'Chutz...] is not considered a Lechi!

Rejection: Even if he held that it is considered a Lechi, it is Mefulash, for Rav Yosef forbids at the side of a Rechavah according to everyone, even according to the opinion that it is considered a Lechi.

Explanation #2 (cont.): [Rav Sheshes said that even if Rav Yehudah learned from Rav,] there is no contradiction in Rav. This is when they were Me'arev. I.e. Rav Yehudah discusses when it ends in the middle, like Rav Yosef explained;

Even though [Rav Yehudah] does not distinguish when it is permitted, this is no problem. Since Rav taught both, what he taught Stam (i.e. what Rav Yehudah taught above, which he received from Rav), he explained here.

Also, since Rav holds that Nir'eh miba'Chutz is not considered a Lechi, he was not concerned to specify that he explains when it ends in the middle of the Rechavah, for if it ends at the side, there are two Re'usos (it is Mefulash, and there is no Lechi).

Implied question: Rav Yosef holds that Nir'eh miba'Chutz is considered a Lechi, like he derives below from Rav Huna's teaching!

Answer: Even so, [Rav Yosef] establishes Rav Yehudah's teaching when they were Me'arev, because Rav Yehudah's initial words (7a, "this is only when there is a Sartya on each side") were in the name of Rav, it seemed to Rav Yosef that also his final words (Rav Yehudah concluded, "if the Mavuy ended...") were in the name of Rav;

Implied question: Rav Yehudah said Stam, and did not specify in the name of whom he says. Also Rav Yosef said Stam in the name of Rav Yehudah (he did not say that Rav Yehudah heard it from Rav)!

Answer: Even so, it seemed [to Rav Yosef] that also this was in the name of Rav, and Rav holds that it is considered a Lechi.

Note: Tosfos asked above (b) that it was not appropriate for the Gemara to say (8a) that Rav Yehudah and Rav argue about Rav Yosef's teaching, since they do not discuss the Chidush that Rav Yosef came to teach, i.e. that it is forbidden when it opens to the side of the Rechavah!

Support (for Explanation #2, and Answer #2 to Question (b)): Now it is fine that they argue about the Chidush that Rav Yosef came to teach. (Rav did not need to specify that he permits only when it ends in the middle, for this is obvious, like the Ri explained.)

Rejection of support: R. Chananel resolves that it is fine that they argue about Rav Yosef's teaching. Rav Yehudah permits even when [the breaches] are opposite each other, like Rav Yosef, and Rav holds like Rabah, who requires that they are not opposite each other.

Support: Also below it connotes that Rabah argues with Rav Yosef, for it asks "according to Rabah, who said that one opposite the other is forbidden..."

Question: However, [according to this] it should have said that [Rav and Rav Yehudah] argue like Rabah and Rav Yosef!