Conclusion
Leonardo Da Vinci was inspired by a statement of Vitruvius on the hu­man body inscribed in a circumference and in a square; but to settle the circle onto the square according to his own idea he had to adopt com­pro­mises, because his construct is not real… and it leaks like a sieve.
The much vaunted Vitruvian man, although affecting ± the ‘collective un­con­scious’ of half the world Ø ±, is a false ideographic which boasts a per­fect ratio: that from a man framed into a square to the same inside a circle that wont even fit by itself.
But what is worse, whether Le­on­ar­do Da Vinci did it in who­le aware­ness or not, from the hermetic and subliminal point of view he acted in re­verse of the so much felt leitmotiv of Vitruvius, which albeit reflexly, is mo­st­ly awarded to him with full hands.
That sketch of his, caged the man inside the [phys­i­cal] square, hinting and clip­ping at a time the illusion of being able to move in the circle [of spiritual vibration], a cosmic longing – for those who want to read it – paralyzed by the roof of the head line [worldly rationality, instead of the irrational Golden Ratio?]. Far away from being a microcosm of the uni­verse! Shall we apply such vision of the microcosm to the universe itself?

In a nutshell, the second pair of arms, as for the spread legs, had to be de­vo­ted to the circle and not relegated to the square where instead Le­on­ar­do in­tend­ed to con­fine them, distorting the esoteric, existential and evolutionary sense of the symbolism (and its correct proportions).
Only the solution achieved right here may be the real answer to this an­cient and actual research, and to the Vitruvius intuition and aim; hence if you ex­pect a step forward, here it is:

t
he heart is the human reference center, i.e. his Golden Ratio within  the Cre­ation Con­scious­ness! This means that starting from the heart we could even geometrically draw all pa­ram­e­ters of the structure of man, either phisical or ultra phisical.

From his own detailed annotations we can deduce that the Golden Ratio was not known or familiar to Leonardo.
Though I suppose he can't be held completely responsible for the mis­lead­ing fame of this pattern. Could he ever have foreseen how this table, even with its outstretched arms and shortened legs, would have co­n­qu­ered the world centuries later in full celebrity?
Or was it only the shallowness of oth­ers to have mounted this myth?
So, rather than to his intention to apply it, any search about the Di­vine Pro­por­tion tro­ugh his sketch could take on a meaning right as if done on any av­er­age struc­tu­re of an ideal human body, provided its erect po­si­tion with hor­i­zon­tal­ly out­stret­ched arms de­lin­e­ates the Vitruvian squ­are, since this was the only un­equiv­o­cal framing.
For such a case, that is the path of this study, the Golden Section applies in at least all the ways delined herewith; which was our goal.