Responsa על חולין 95:6

I also asked [in my dream] regarding the lung of an animal which is found to be stuck to the ribs by the sectioning of the lobes¹See Chullin 48a:7, which is kosher, but only when the lung is attached to the flesh [of the ribs] and not to the bones²See Rashi on Chullin 48a:8 and Rif Chullin 12a:2. Is it however enough that it is attached to one of them, the flesh or the bones, to be considered kosher?³This is the opinion of Rabbeinu Gershom, cited in Tosafot on Chullin 48a:8

On the eve of the twenty-ninth of Elul of the year 4963¹September 1203 in the Christian calendar, an animal was brought before us with its lung attached to the rib-cage, and we forbade the animal. Afterwards, the learned Rabbi Mordechai came and showed that one of the ribs was broken. Then the butcher came to remove the lung, and when it was detached in pieces, a small piece was left stuck to the broken rib. We were unable to inspect the lung further, and we were unsure about this matter. For some say that there are manuscripts²of Chullin 48a:3, see Rashi on Chullin 48a:5 for his version without the following line. See also the discussion in Hamaor Hakatan and Milchemet Hashem on Rif on Chullin 12a on this issue and the different versions in Spain and France that claim that only if the lung was inspected can we attribute any defects to a damaged rib and even if there is no damaged rib, we can also presume the validity of the animal, unless the lung is perforated. We learn from this that when there is definite proof of a broken rib, there is no doubt about the lung and every imperfection is attributed to the rib, even if the lung was not inspected. Inspection of the lung, according to this, is only necessary when there is no damage to the ribs. This is especially so in our case of the lung, since it originally inflated completely when one blew into it except for the one place where it was cut too much. There are those who disagree, however, and say that even when there is proven damage to the rib the lung still needs thorough inspection, and if the lung cannot be inspected the animal is declared invalid³See Hasagot HaRaavad on Mishneh Torah, Shechitah 7:5. I asked [in my dream] which opinion is correct, and whether the lung that came before us is permitted or forbidden.