2
This is one of those issues where one must simply make a decision as to how one chooses to delineate the significators (karakas) in one's own practice. If Taurus is the neck, and the Second House is also the neck, then one soon encounters apparent contradictions -- if, for example, Sagittarius is the Lagna, then both Taurus as Sixth House and Capricorn as the Second House will represent the neck, making it virtually impossible to delineate clearly unless one indulges in the kind of juggling where one plays one karaka off against another, seeking the broadest consensus among many factors.

Varaha Mihira (Brhat Jataka 1:4) delineates the Kalapurusha by signs rather than houses. Most of the classical texts (e.g. Saravali, Hora Sara, Jataka Parijata, and Phaladipika) assert that Varaha Mihira's authority is beyond question. Even much later works such as Prasna Marga make the same assertion.