Chullin 20 a-b The Neck - אין עיקור סימנים בעוף

The neck houses three vital channels of life: the simanim, the trachea, oesophagus,  and the carotid arteries. In Kodshim the focus is on the arteries, in Chullin on the simanim. Severing the simanim is the condition for removing the animal from tumat beveila whereas severing the arteries is the way to prepare the animal to be kosher for consumption by a Jew. In the human neck the trachea also serves as the channel for speech. Speech, רוח ממללא, distinguishes human from animal; for speech is the deepest expression of neshama. Source Sheet