• ניקב קרום של מוח

The Mishnah on Daf 42a taught that ניקב קרום של מוח – if the membrane of the brain was punctured, it is a טריפה. Rav and Shmuel say this refers to קרמא עילאה – the upper membrane, even if the lower (inner) membrane was not punctured. Others say עד דאינקיב תתאה – it is not a tereifah until the lower membrane is also punctured. Bar Kappara identifies where the brain ends and the spinal cord begins: מוח כל מה שבקדירה נדון כמוח – regarding the brain, whatever is inside the cranium is considered like the brain (and is a tereifah with even a minimal hole). התחיל למשוך נדון כחוט השדרה – From where [the brain] begins to extend beyond the cranium, it is considered like the spinal cord (and only a mostly severed membrane is a tereifah). Rebbe Yehoshua ben Levi explains further: כמין שני פולין יש מונחין על פי הקדרה – there are two bean-shaped structures lying at the cranium’s opening. Whatever is from the “beans” and inwards is considered the brain, and whatever is outside the “beans” is considered the spinal cord. But that which is parallel to the “beans” themselves, he does not know, but it is reasonable that it is considered inside the cranium.

• ניקב הלב לבית חללו, קנה הלב

The Mishnah taught that ניקב הלב לבית חללו – if the heart was punctured into its chamber, the animal is a טריפה. Rebbe Zeira asked if this refers even to בית חללו קטן – a small chamber of the heart, or only toבית חללו גדול – its large chamber. Abaye attempted to prove it means the large chamber, but his proof is rejected, and the Gemara concludes that the expression should also include a smaller chamber.

Amoraim debate the status of קנה הלב – the pipe of the heart. Rav says it is a tereifah במשהו – with even a minimal hole, and Shmuel says ברובו – when its majority is severed. Rav defines the "קנה הלב" as חלב שעל גבי דפנות – the fat that is on the walls, which is explained to refer to the walls of the lungs, i.e., the pipe which runs between the lungs and connects to the heart cavity (the aorta). When Rav’s ruling was reported to Shmuel, he commented: אי הכי אמר אבא – if this is what “Father” (Rav) said, לא ידע בטרפות ולא כלום – then he does not know anything at all about tereifos!

• חוט השדרה שנפסק

The Mishnah taught that if the spine was broken and the spinal cord was severed, it is a טריפה. In a Baraisa, Rebbe says: חוט השדרה שנפסק ברובו – it is a tereifah if the spinal cord was mostly severed, but Rebbe Yaakov says אפילו ניקב – even if it is merely punctured, it is a tereifah. In practice, Rebbe ruled stringently like Rebbe Yaakov, but Rav Huna said the halachah does not follow Rebbe Yaakov. The definition of the spinal cord’s majority is debated: Rav says it means רוב עורו – most of its “skin” (i.e., the meninges surrounding the nerves), and others say רוב מוחו – most of its nerve tissue. According to this second opinion, it is certainly a tereifah if most of its “skin” is severed, because the nerve tissue will decay and fall out. Regarding the first opinion, that Rebbe’s ruling was about the majority of its “skin,” Rav Huna said that it is irrelevant whether the nerve tissue itself is severed. Rebbe Yehoshua ben Levi ruled that נתמרך – if [the nerve tissue] was liquified, which is defined as כל שנשפך כקיתון – where it pours like a jug of water, it is a tereifah. נתמסמס – If it was only softened, defined as כל שאינו יכול לעמוד – where [the spinal cord] cannot stand on its own, it is still kosher.