1. NUCCA X-Ray Analysis

2. Analysis Equipment
Cephalometer
Circumscale
Relatoscope
Vertex square

3. Lateral Film PURPOSE: To obtain the S line of the atlas
To tell if the atlas has gone inferior or superior
To determine where to take the Nasium

4. Lateral Film Analysis S Line
Place a dot where the posterior arch of atlas meets the lateral mass
Place a second dot about 1/3 down along the length of the posterior arch of atlas
*Note that because of how the Nasium film is taken, if the S line does not go through the mastoid markers, you must move the line up/down in a parallel fashion so that it does. This way it will be taken at the proper angle.

5. S-Line

6. Nasium Film PURPOSE: To determine atlas laterality
To determine upper and lower angle to determine the basic type
To determine APL, A/O, C/A, Ang, At, OD, BC, Sp
To calculate the height vector
To determine if C2 spinous rotation is present (torque)

7. Nasium Film Atlas Plane Line (APL)
Place a dot on the lower border of the posterior arch where it crosses the lateral masses on each side of atlas

8. Nasium Film Central Skull Line (CSL)
Mark the squamous suture on each side of the head
Mark the vertex of the head on each side
The CSL will only be determine using the area between these two points

9. Nasium Film CSL Continued
Use the Cephalometer to match like points on either side of the head in order to determine the center of the skull
Mark a lower pivot point intersecting the APL
Mark an upper pivot point at the top of the skull

10. Nasium Film CSL Continued
Starting with the lower pivot point, make your way up the skull finding like points with the cephalometer by keeping the lower pivot point in the slot. The line should match up with the two pivot points
Then make your way down with the upper pivot point
Repeat
If the line shifts, you have the wrong pivot points and need to redo
Once you have the best points, mark the CSL with a solid line

11. Nasium Film Atlas Laterality (At)
To find laterality measure the side of the acute angle between the CSL and APL

12. Nasium Film
Head Tilt
To find the head tilt, measure the angle between the true vertical and the CSL

13. Nasium Film Condylar Circle
Mark the outer 1/3 of the surface of the occipital condyles
Using the circumscale, find the best fit circle = c
If it comes out to ½, round down

14. Nasium Film Axial Circle A B
Place a dot (A) on the most lateral aspect of the superior surface of C2 on each side
Also place a dot (B) on the medial aspect of the superior surface of C2 on each side
Connect those dots on each side
From the medial dots, place another dot (C) 3/32’’ down perpendicularly from that line
Use A and C to find the best fit circle for axis = a
If it comes out to ½, round up A B

15. Condylar and Axial Circles

16. Nasium Film
Odontoid Center (OD)
Mark the center of the Odontoid

17. Nasium C2 Body Center (BC)
Using the dots on the lateral aspect of the superior surface of C2, place the center of a protractor on each dot and scribe and arcs above and below
Use a straight edge to connect the two intersections
Draw a small line down the center in the middle of the intersections

18. Nasium Film BC Continued
Use the relatoscope that corresponds to the condylar circle
Square up atlas so that the horizontal lines of the relatoscope are parallel to the APL and the lateral masses are boxed in equally
Determine the degrees (if any) the body center line is off from the 0 mark on relatoscope
If BC is on the same vertical line as the 0 mark then BC = At

19. Nasium Film C2 Spinous (SP)
Mark the inferior bifurcation of C2 spinous
Use the relatoscope again to compare position of C2 spinous to atlas like you did with BC
The lateral film can help you locate its position if its hard to see by comparing where it is on the lateral film in relation to the posterior arch of atlas

20. OD/BC/SP

21. Nasium Film Fixed Point
Mark the lateral aspects of the zygapophyseal joints of C7
Determine the midpoint
Mark a point (D) between BC and SP if not on same vertical line
Connect the midpoint of C7 to D dot

22. Nasium Film Lower Angle
Measure the acute angle between the APL and the fixed point line

23. Nasium Film
Height Vector Components PL
A/BC
C/A
Ang

24. Height Vector CalculationsPL
Use a true horizontal and move it up/down until it matches up where the APL crosses the ramus of the jaw on the side opposite of laterality and draw a small straight reference line on the side of laterality
Measure how far above or below the APL is compared to that true horizontal
If APL is lower by:
1/16th “  - ¼”
2/16th “  - ¾”
3/16th “  - 1’’
If APL is higher by:
1/16th “  + ¼”
2/16th “  + ¾”
3/16th “  + 1’’

25. PL

26. Height Vector Calculations
A/BC
Compare the amount of atlas laterality due to atlas side slip (ss) versus head tilt (ht)
If ht ≥ ss, then A/BC = -1/2 ht but only up to amount of laterality
If ht < ss, then A/BC = -1/2 ht
If ht = 0 or if it does not contribute to laterality, then A/BC = 0
If BC > At like in a Type I with a large lower angle, then A/BC = +1 for the first degree extra

27. Height Vector Calculations
This is equal to + (a-c)⁄2

28. Height Vector Calculations
Ang
Take the difference of At – lower angle
For contralateral acute angles
+ ¼” for every 1° difference
For ipsilateral acute angles
- ¼” for every 1° difference
If the lower angle is less than or equal to atlas laterality, then Ang = 0

29. Height Vector Calculation Practice
At R2
OD R2
BC R2
SP R2 3c
+ 4/16th 8a L6
PL = + 1 ¼
A/BC = 0
C/A = + 2 ½
Ang = + 1
_______________
+ 4 ¾

30. Height Vector Calculation Practice
At R4 (RS)
OD R4
BC R1
SP R4 3c
+ 2/16th
10a L4
PL = + ¾
A/BC = - 1 ½
C/A = + 3 ½
Ang = 0
_______________
+ 2 ¾

31. Height Vector Calculation Practice
At R4 (R4)
OD R4
BC R0
SP R4 3c
5 ½a L0
PL = 0
A/BC = - 2
C/A = + 1 ½
Ang = 0
_______________
- ½

32. Vertex Film PURPOSE: To determine C1 rotation
To determine anterior/posterior vector

33. Vertex Film
Mark the anterior and posterior aspect of both lateral masses
Mark the center of the transverse foramen and draw a line connecting the two points
Use the vertex square to box in atlas using the lateral masses to make sure all those points/lines are parallel
If the line of the transverse foramen isn’t parallel to the lateral masses, use the lateral masses
Measure the angle between the true vertical line and the transverse foramen or lateral mass line on the side of laterality
If the angle is acute = anterior rotation
If the angle is obtuse = posterior rotation
Vector = 1” for every 1° anterior or posterior

34. Vertex