“IML” Intermastoid Line 

This tool is used to mark the most inferior portion of the mastoid process. 

• Mark the most inferior aspect of the left mastoid process 
• Mark the most inferior aspect of the right mastoid process 
• It will create an IML measurement in the calculation box when completed. 

“ACL” Atlas Check Line Tool:  

This tool is used to mark the most superior aspect of the posterior arch of atlas.   

• Left most superior lateral aspect of the posterior arch where it meets the lateral mass 
• Right most superior lateral aspect of the posterior arch where it meets the lateral mass 

“APL” Atlas Plane Line Tool: 

This tool is used to mark the most inferior aspect of the posterior arch of atlas.   

• Left most inferior lateral aspect of the posterior arch where it meets the lateral mass  
• Right most inferior lateral aspect of the posterior arch where it meets the lateral mass 

• Atlas check lines should turn green if done correctly 
• It will create an IML measurement in the calculation box when completed. 

“C” Condyle Tool: 

This tool is used to represent the left and right condicular surface.    

• Mark L Most superior lateral aspect of the condyle where the superior tip of Atlas points to.  
• Divide condyles into thirds and select 1/3 of the way down the condyle and mark the next point 
• Do the same on the right condyle. Reopen Films 

“Ct” Condile Circles Template: 

This tool is used to double check the condular measurement taken in the steps prior.  

• Select the tool 
• Select near the condyle points just made and it will put a tool that looks like the image to the right.  
• Select “Escape” 
• Select the box onto the tool to change it red 

• Move the arches on the tool to find the best fit condylar measurement. 
• Once found, select the “?” key. Enter the number of the best fit. Ex: 3 
• Hit “enter” 
• This is a double check on the condylar measurement and overrides the original found from the “C” tool.  

“A” Axial Tool: 

This tool is used to represent the most C2 articular surface. 

• Select most superior and lateral aspect of C2 superior articular surface on the left  
• Then select the dip just before the dens and mark the most superior aspect  
• Mark the most superior and lateral aspect of C2 surface on the right  
• Mark the same superior aspect of the dip on the right before it meets the dens 

“At” Axial Circles Template: 

This tool is used to double check the axial surface measurement taken in the steps prior.  

• Select the tool 
• Select near the axial surface and it will put a tool on the screen that looks like the image to the right.  
• Select “Escape” 
• Select the bod on the tool to change the tool to red 
• Move the arches on the tool to find the best fit axial measurement by lining up the 4 points most inferior.  
• Select the “?” key. 
• Hit enter  

“AR” Angular Rotation Tool: 

This tool is used to represent the most C2 articular surface. 

• Select same axial points on C2 lateral superior aspect of the body on the L then R  
• Then Select the middle of the C2 Bifurcation of the Spinous process “x” by following the T1 spinous up to C2. This will help to locate the C2 spinous.  
• Select the most lateral aspect of the T1 body on the L then R 
• Select the “x” in the middle of T1 spinous  

“CSL” Central Skull Line 

This tool is used to represent the center of the skull.  

• Reposition the film to see the Atlas and top of the skull. 
• Mark the sagittal sutures of the skull with the line tool 
• Select the “CSL” tool 
• Select the center of the skull and it will position the instrument in the middle of the skull. 
• Select the box in the middle of the instrument to move instrument. Center the instrument horizontally to compare skull margins until they are even on Left and Right sides. 
• Rotate instrument using the “<” and “>” keys to find the best fit. 
• Double Pivot Point: 
• Compare 2 inferior lines on the instrument and center them Lt and Right. 
• Then look up the instrument and center the upper points. 
• Then check the lower points. 
• Then the upper until both are centered and no adjustment needed.  
• Then lean back and look to see if the line represents the center of the skull. 
• Hit the “?/” key to set the CSL.  
• Select the Nasium Calculation tool 
• Place the AT BC SP (Components of the tool) on the side of laterality. 
• Place the other calculation on the opposite side of laterality. 
• Reset plane line so that it accommodates for the side of laterality!!!!!!! 
• Put both nasium and vertex films on the screen (split screen) 
• Move NUCCA vertex calculation box to the side of laterality. 
• Double click on the vertex box and put in laterality, condylar measurement, atlas laterality value. 

DECISION MAKING POINT: 

• On the nasium put a text box on the side of laterality and type in the listing. 
• If atlas and spinous are the same then inferior torque, if opposite then superior. 
• Evaluate film for headpiece placement. 
• 1, 2, 3, 4, on A, B, C, D 
• Draw where to put the headpiece. 
• Write in if clockwise (cw) or counterclockwise (ccw) torque on listing.  
• Close & Save 
• Mark Films as Read.