The Mishnayot on today’s daf continue the discussion of mumin – blemishes – that would preclude a firstborn animal from being sacrificed and would allow the animal to be slaughtered and eaten by a kohen outside of the Temple. Among the blemishes mentioned are if its nose is pierced, damaged, or split, or its upper lip pierced, damaged, or split. The Gemara explains that these are only considered blemishes if the nostrils are perforated right through from the outside, but if the perforation is inside, it is not considered a blemish.
Rashi explains this to mean that the perforation is made on the outer part of the animal’s nose. According to the Rambam, this refers to perforations made for a nose ring that is at the end of the animal’s nose. Since the nose is extended outwards, such perforations would be considered to be “outside.”
Another example of a blemish of the jaw and mouth area is if the animal’s ḥutim ḥitzoniyot (translated by some as gums and by others as incisors) are broken off or leveled to the gum or if the penimim (the inner teeth, i.e. the molars) are torn out completely.
The mouths of both cows and sheep contain incisors in the front part of the bottom jaw, but in the upper jaw there are no teeth in front – rather there is periodontal cartilage. Rashi explains that the ḥutim ḥitzoniyot of the Mishna refer to damage in this area of the mouth, on the top as well as on the bottom where there are spaces between the incisors. The penimim are the wide molars in the back of the animal’s mouth on both the top and the bottom that have many bumps and protrusions and appear like two teeth next to each other.