NOTES on my APPROXIMATIONS:
1: Reference horizonts and verticals are those of the cephalostat which is aligned with the picture plane.
2: All points are APPROXIMATE locations.
3: All my NOTES and approximate measures are used to arrive at a basic and general conclusion of which rotation; CCW or CW. This is not an 'exact' or complete ceph analysis. It's meant to be very straight forward demonstration in applying elementary geometry concepts to those in maxfax. In this demonstration we look at the ceph of a person who THINKS he needs CCW, mark out some basic points on the ceph which can be approximately found even by someone who does not 'know a lot', (by looking for diagrams as to where those points are located), measure the angles with a very LOW TECH device (hand held protractor held to the screen) and compare to a diagram (found in the the educational section) having to do with rotations of a triangle.
OBSERVATIONS:
S-N line close to 0 degrees inclination from horizont. So, angles formed from an S-N line that's horizontal, (such as SNA and SNB), will be HIGHER than the norms when the norms of the SNA SNB angles are with reference to the S-N line being inclined about 7 degrees away from a true horizont.
SNA 87, 82 ± 2° is norm. So, if we adjust for (subtract) the extra 7 degrees kicked up by the horizontal S-N line, the SNA angle would be approx within a norm for someone with a horizontal S-N line. Basically, we wouldn't use an SNA of 87 as definitive that someone has an overly protrusive maxilla.
SNB 92, 80 ± 2° is norm. So, if we adjust for (subtract) the extra 7 degrees kicked up by the horizontal S-N line, the SNB could be looked at as being 85 deg. However, even with the 7 deg. adjustment it is BEYOND the norm and indicates that the mandible is protrusive.
As to the above observations of the SNA and SNB angles when the S-N line is horizontal, the SALIENT thing to look at is the ANB.
angle ANB= SNA- SNB and is approx. -5 (negative 5) which is OUTSIDE normal range and is CONSISTENT with the UNDERBITE seen.
ANS-PNS line (maxillary plane) approx 0 deg (horizontal) .
The OP line looks to be on 'flat' side as in something to INCREASE and not to decrease with CCW.
MPA appox 21- 22 deg, within normal range of 17-28 deg. So, not something to set about decreasing via CCW whereas increasing via CW would still be within norm.
Basic conclusion: The lines and angles looked at here, even though approximate, DO NOT suggest CCW rotation. They suggest clockwise rotation. CW-r of the yellow triangle.
ETA: A diagram is included in this post.
