Try cephX to learn the points. SCROLL DOWN on this page:
https://cephx.com/tag/cephalometric-anlaysis/For norms for common relationships like OP, MPA, etc., you can just google; 'norm for____'. But you have to be careful because they can be relative to DIFFERENT types of ceph analysis of which there are MANY. For example, a Steiner analysis (which is quite popular), the 'S' point is used (because it's easy to see on the X ray and easier than 'Frankfort horizontal where one of the points (Po) that make up that FH LINE is hard to find on the ceph). That is very good for finding SNA, SNB and ANB angles and then looking up the norms. However, the MPA and OPs (angles) will DIFFER in a Steiner analysis than from an analysis where the Frankfort horizont is used because different lines (by connecting 2 points) are used to reference the angle.
Myself, I like the Arnett/Gunson type analysis which posits WHERE a 'true vertical line' needs to pass through and sometimes, this also posits a true HORIZONT (perpendicular to the TVL) that is parallel to the floor. But it's not always the Frankfurt horizont simply because the FH, itself, might not be parallel to the floor in all people or they might not hold their heads so it is. This often involes rotating a ceph clockwise (and degrees of rotation can differ depending on the case) to where all the places they want the TVL to pass through. Sometimes FH is perpendicular, sometimes not. I think something in that venue can be found in the articles listed on the educational section.
A lot of maxfax concepts are very INTUITIVE providing you have basic elementary geometry under belt can 'relate' it to maxfax concepts. Helps if you can rotate things in your head. The more above average IQ one has, the easier it gets.
