Resize the image and click to view the initial Golden Sections, and the left arm's arc of abduction centered on their natural cross point, being vertically a bit wider than the right one; this was done for com­par­i­son to show some ver­ti­cal com­pen­sa­tion to the sho­ul­der ro­ta­tion upwards (page 50 click he­re to view, and the Back arrow to exit full image).
The passages through several stages of this search will be proudly rep­re­sent­ed in the next figure, by clicking on which they alternate in an in­struc­tive pro­gres­sion.

The φ plot of the square's half si­de (1.618 of 2, that delimits the he­ight of the shoulders ar­tic­u­la­tion and the extension) [1st click], as it was plot­ted since the page 26 at the ini­tial stage of the study, pink co­lo­red in the fig­ure, was sca­led up to the he­ight of the squ­are, then du­pli­cat­ed in a golden profile [2nd click].
It's interesting to watch better now how the vertex c, i.e. the φ of the man he­ight, that marks the vertical po­si­tion of the soulders, is scaled (white arrow) to the s position, whose ver­ti­cal marks the hor­i­zon­tal pro­por­tion 2/φ of both heads of humerus over the arms extension, as the cross point highlighted above.
This vertical pinpoint of the body upper golden center was also rotated 90° at the page 27 to show the horizontal mirrored sections of the squ­are, match­ing the glenohumeral joints, as well as the 4th Golden Circle from the external circumference, as it will better fit from now on.