Bechoros Daf 45 בכורות דַף 45

A Baraisa teaches that an extra finger which has a bone but lacks a fingernail is metamei (as a detached אבר) through contact, being carried, or אהל. ועולה למנין קכ"ה – And it counts towards the one hundred twenty-five bones for a numeric majority of a human body’s bones (i.e., where there is no flesh).

A Mishnah teaches that רוב בנינו – most of the structure or רוב מנינו – most of the bones of a body are metamei (even through אהל). A Baraisa defines “most of the structure” as two shinbones and one thighbone, which amount to the majority of an adult’s height, and the numeric majority of bones as 125. Since the majority of a person’s 248 bones is obviously 125, the Baraisa is explained to be teaching that even if someone was born with as few as 200 bones, or as many as 281, they are all counted towards the same majority of 125 bones, because זיל בתר רובא דאינשי – we follow the majority of people with 248 bones. The Gemara proceeds to note that women have 252 bones, because the Torah describes her as having שני צירים ושני דלתות – two “hinges” and two “doors.” Rebbe Akiva adds a fifth bone, a “key.” Rav says that none of these additional limbs are metamei with אהל.

A Baraisa states: איטר בין ביד בין ברגל פסול – one who is left-limbed in either his hand or his leg, i.e., he is left-handed or left-legged, he is unfit to perform avodah. השולט בשתי ידיו – Regarding one who is ambidextrous, Rebbe says he is פסול, but the Chochomim say he is fit. The Gemara explains that Rebbe holds כחישותא אתחלא בימין – a weakness developed in his right hand and caused his ambidextrousness, so this disqualifies him. The Chochomim hold that, on the contrary, בריותא [יתירתא] אתחלא [ליה] בשמאל – [additional] strength developed in his left hand and caused his ambidextrousness, so he is fit for avodah.

The Mishnah states: והנושא נשים בעבירה – one who marries women in sin, i.e., he marries someone forbidden to Kohanim (e.g., a גרושה), פסול עד שידירנה הנאה – is disqualified from performing avodah until he makes a vow prohibiting her from benefit. A Kohen who becomes tamei from the dead is disqualified from performing avodah until he accepts upon himself not to become tamei from the dead. [The Gemara later explains, regarding one who is married in sin, that since יצרו תקפו – his desire for his wife takes hold of him, we cannot rely on his commitment to divorce her unless he makes a neder.]

A Baraisa states: נודר ועובד יורד ומגרש – he vows against benefiting from her and performs the avodah, descends from the מזבח and divorces her (meaning, once he made the neder, he may perform avodah even before divorcing her). The Gemara proceeds to explain why we are not concerned he will have the neder annulled by a חכם. It answers that either he must detail the reason for the neder (and the חכם will not annul it), or he must make the neder ברבים – in public, or על דעת הרבים – on the public’s consensus, which cannot be annulled.