Like special nodes, we crossed two original horizontal short lines under the knees, just at the ½, to half the height of the quarter of square xylm, another to the xy, and a vertical one on the left shoulder, which results exactly covered by the line yΦ! and I can't see any other reference for, if not the shoulder joint (wrong to the right side on the original drawing).
However, this partition applies to both the arms, reciprocally mirrored inside a golden area by the trunk with it's own resulting golden area.
Whilst the golden ratio from each hand to the opposite shoulder is symmetrical, occasionally, we should think, the other line to the shoulder is out of place compared to the armpit; by the way, the single figure is not 100% regular, the square needed to be slightly enlarged in height (lighter area adjusted) as the sides were not aligned; perhaps the same paper may have shrunk in time, mainly the right lower side of the page, beyond the writings; however Leonardo Da Vinci could not enjoy a CAD).Now, we may not know if Leonardo Da Vinci took into account the Divine Proportion in his works, but these lines like some others which should mark the anatomy and the 4 squares and their portions, match the start and ending of a process that is revealing by now two main Golden ratio divisions: vertical and horizontal of the same square.
And that's not all. We can proceed to one more look into, to check how the common central area between the yΦ, side of the square yΦml and the symmetrical one, taken inside the big square, holds now the golden rectangle [green] lmcΦ starting from the navel (we will analize later a small difference, if true; since the real center of the adjusted circle is slightly lower than the consequent navel), which suitably separates the chest from the head at its Φ height.On the other hand, we are not necessarily investigating on the Vitruvian man, as much as on the Divine Proportion in the human body, what this eloquent figure invited us to do.