Kiddushin 25A

יתרת, וחתכה ⁠– עבד יוצא בהן לחירות. אמר רב הונא: והוא שנספרת על גב היד.

an extra finger, i.e., 6 fingers on his hand, and the master severed it, the slave is emancipated by means of this injury. Rav Huna says: And this halakha applies when the finger can be counted along the back of the hand, i.e., the extra finger is on the same line as the others. If it protrudes from another spot, then it is not classified as a finger but a mere growth, and destroying it is not considered the removal of a limb.

סבי דנזוניא לא אתו לפירקיה דרב חסדא, אמר ליה לרב המנונא: זיל צנעינהו. אזל אמר להו: מאי טעמא לא אתו רבנן לפירקא? אמרו ליה: אמאי ניתי? דבעינן מיניה מילתא ולא פשט לן. אמר להו: מי בעיתו מינאי מידי ולא פשיטנא לכו?

§ The Talmud relates: The Elders of the city of Nezonya did not come to Rav Ḥisda’s lecture. Rav Ḥisda said to Rav Hamnuna: Go and ostracize them [tzaninhu] because they act disrespectfully toward the rabbis. Rav Hamnuna went and said to the Elders of Nezonya: What is the reason that the rabbis did not come to the lecture? They said to him: Why should we come, as we asked him about a matter and he did not resolve it for us. We have nothing to learn from him. Rav Hamnuna said to them: Have you asked me anything that I did not resolve for you? Ask me your question.

בעו מיניה: עבד שסרסו רבו בבצים, מהו? כמום שבגלוי דמי, או לא? לא הוה בידיה. אמרו לו: מה שמך? אמר להו: המנונא. אמרו ליה: לאו המנונא, אלא קרנונא.

They raised the following dilemma before him: With regard to a slave whose master castrates his testicles, what is the halakha? Is that considered an exposed blemish that is sufficient to emancipate him or not? An answer to their dilemma was not available to Rav Hamnuna. They said to him: What is your name? He said to them: Hamnuna. They said to him in jest: You should not be called Hamnuna, a good hot fish; rather, your name should be Karnuna, a cold fish that is no longer tasty.