From top of head to floor is height.
The variables you are asking about are specific to garments. Example: Trousers would not use a neck to seam variable.
These variables are built from body measurements, but they are not body measurements, they are specific to a particular garment of a particular style.
They are defined for your pattern in the Increments table, and are saved within the pattern.
This distinction between body measurements and the garment-specific variables is not apparent in patternmaking books because these numbers are usually included in the same table for a pattern.
Each pattermaking system uses some body measurements but not all body measurements.
Patternmaking books explain a few basic patterns built from that system’s measurements. Each pattern uses only a subset of the system’s body measurements. Each pattern is presented as the basis for many other shirts. This hides the reality that there are literally hundreds of variations to make that basic shirt, from which many other shirt styles can be developed. You see the problem?
To further confuse things, patternmaking books frequently use standard sizing tables which include measurements of the finished garments in the same tables with body measurements used to make the pattern. They don’t explain how these finished garment measurements were derived from the body measurements. They hide essential info you need to make properly fitted clothing.
The list of garment variables might as well be infinite, because we can’t anticipate which measurements you like, which systems you like (or if you just ‘shoot from the hip’),
or which garment variables you want to use.
Multiply the number of all patternsystems (including your own personal shortcuts and preferences) with the number of all possible garments and you will realize the magnitude of the problem.
Since we can’t anticipate the variables that you will want, we could implement custom macros. Would you want to create your own macros, and then select your ‘shirt’ macro whenever you make a new shirt?