Measuing/analysing posture in saggital plane

Hi, in the process of doing my dissertation (sport and exercise science, applying for MSc physio after). Analysing posture in amateur rugby uni players using non-invasive surface topography methods.
Taken photographs from posterior view and analysed using POTSI.
Taken photographs from lateral view and analysed head/neck/ shoulder using craniovertabral angle.
***Looking for another method to analyse the entire head,neck, shoulder, back posture from lateral view photographs***
Is there anyway to measure angle of curvature in the back from the lateral view? basically like cobb angle but from the side. I have done a lot of research and journal searches but im not sure if such a method exists and if it does, what its actually called?
Any help would be greatly appreciated, even just the name of the method so I can research it.
Cheers!!!

dear Jsharp
There actually is.
Take a look at Physio Prospective study. Part of the assessment of the scoliosis patients is with the use of a plumbline and ruler. We are able to measure the deepest part of each curve in this manner.

HERO!
thanks very much estherderu :)