Metaphorical meanings of kephale: literal, headlong, whole person, extremity, prominent part, conclusion, authority

Mike lists the possible metaphorical meanings of kephale: (1) literal physical head, (2) headlong (falling headlong), (3) the whole person (counting heads), (4) extremity (heads of a river = source or mouth), (5) prominent part, (6) conclusion of an argument (coming to a head), (7) authority/ruler. When you rule out inapplicable meanings for Paul's context, authority is the remaining meaning that fits, especially given contextual terms like 'submission' and 'be subject to.'