Why from the neck? Said Rav Kahana, the word "shechitah" says it: "shach" means something that bends, that is the neck, and "chat" means to prepare. But the tail also bends, so perhaps we should cut from the tail? - No, the tail is already bent, and we need something that bends occasionally. But perhaps we should cut from the ear, because it sometimes bends? - No, we need the lifeblood, and it does not go from the ear. Still, how would we know the five disqualifications of the shechitah, which are pausing, pressing, burrowing, cutting beyond and tearing? - We are forced to conclude that cutting from the neck was taught to Moses on Sinai and is not based on a word in the Torah.
Rav Yeimar said, the word slaughter, "zavach" means to cut where it (the blood) flows ("zav"). But perhaps we should cut from the nose, from which mucus flows? - No, mucus always flows, and blood - only when cut.
Art: Thomas Wade - Man Tickling a Woman's Nose with a Feather