The high point shoulder or HPS point is used as the base for several vertical measurements. Refer to the hps documentation for information on how to locate this point.
The high point shoulder (HPS) to bust measurement runs from your HPS down to the line that forms your bust span.
To measure your HPS to bust, first localize your HPS point. Then measure straight down to the line that forms your chest circumference/bust span.
The point of this measurement is to locate the fullest part of your bust vertically on your torso.