i think i have a good idea that "z" is the vertical load or tension on the neck since "z" is elevation for other equations i use frequently (ChE). but just for the record, what is considered to be "x" and "y" in a car? is "x" forward motion and "y" lateral?

cause to the first users of grids in algebra, "x" is usually laid out on the paper for left to right, "y" is vertical and "z" goes into the paper and some have construed that to be forward or behind, etc.[/b]
Yes, Z is vertical. The X axis is front-to-rear (from the dummy's perspective) and Y is left-to-right.

also, the threshold of injury for a typical hard hit of 50 g's, etc. would be nice. i was quite impressed with the numbers on your website and i think a line for injury threshold would be a good way to illustrate what is above and below (essentially, inadequate and adequate), etc. would be nice and quick and most of all, intuitive.[/b]
That's a good point. Unfortunately, threshold limits are not available for all measures, but we could include them where available.

and will there be any three dimensional graphs? cause in any crash video i have seen, the neck is going in all three directions at once and i am assuming that the resultant vector/force (i hope that makes sense cause it has been way too long since i had to use or listen to these kind of words!) is part of what has to be considered.
[/b]
This is the appeal of a summary measure. Given the bone geometry one can determine the unit stress and relate it directly to the bone strength. In other words, the net effect of all these loads acting simultaneously can be analyzed to be either above or below the fracture threshold. This would not require a 3D graph--although one could be used.

I think we will be keep it rather simple, with references to more detail as some sort of appendix.

Thanks all.