Joseph,
Arms, from the Gemara in Kesubos, are clearly only a Daas Yehudis (i.e. minhag). Legs, on the other hand, are mentioned in the Gemara as erva. The Shulchan Aruch (following the Rambam) understands legs as just an example of something you might have thought was not a makom mechusa, but really is. To me this is a more dochek reading of the Gemara. I explained why at length in a previous thread but I can’t remember what it was called.