NUCCA X-Ray Analysis

Analysis Equipment

Cephalometer

Circumscale

Relatoscope

Vertex square

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

Lateral Film Analysis

S LinePlace a dot where the posterior arch of atlas meets

the lateral massPlace 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.

S-Line

Nasium FilmPURPOSE:

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)

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

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

Nasium Film

CSL ContinuedUse 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 APLMark an upper pivot point at the top of the skull

Nasium FilmCSL 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

Nasium Film

Atlas Laterality (At)To find laterality measure the side of the acute angle

between the CSL and APL

Nasium Film

Head TiltTo find the head

tilt, measure the angle between the true vertical and the CSL

Nasium Film

Condylar CircleMark the outer 1/3 of the surface of the occipital

condylesUsing the circumscale, find the best fit circle = c If it comes out to ½, round down

Nasium FilmAxial Circle

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 ABB

Condylar and Axial Circles

Nasium Film

Odontoid Center (OD)Mark the center of the Odontoid

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

Nasium Film

BC ContinuedUse the relatoscope that corresponds to the condylar

circleSquare 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

Nasium Film

C2 Spinous (SP)Mark the inferior bifurcation of C2 spinousUse 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

OD/BC/SP

Nasium FilmFixed 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

D

Nasium Film

Lower AngleMeasure the

acute angle between the APL and the fixed point line

Nasium Film

Height Vector ComponentsPLA/BCC/AAng

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’’

PL

Height Vector Calculations

A/BCCompare 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

Height Vector Calculations

C/AThis is equal to + (a-c)⁄2

Height Vector Calculations

AngTake the difference of At – lower angleFor 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

Height Vector Calculation Practice

At R2

OD R2

BC R2

SP R2

3c

8a

L6 PL = + 1 ¼A/BC = 0C/A = + 2 ½Ang = + 1_______________ + 4 ¾

+ 4/16th

Height Vector Calculation Practice

At R4 (RS)

OD R4

BC R1

SP R4

3c

10a

L4 PL = + ¾ A/BC = - 1 ½ C/A = + 3 ½Ang = 0_______________ + 2 ¾

+ 2/16th

Height Vector Calculation Practice

At R4 (R4)

OD R4

BC R0

SP R4

3c

5 ½a

L0 PL = 0A/BC = - 2C/A = + 1 ½ Ang = 0_______________ - ½

Vertex Film

PURPOSE:

To determine C1 rotation

To determine anterior/posterior vector

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

Vertex