Skull (Caldwell view)

The Caldwell view is a caudally angled PA radiograph of the skull, designed to better visualise the paranasal sinuses, especially the frontal sinus.

Patient position

• the patient is seated in front of the upright detector
• the patient's forehead is placed against the image detector
• forehead and nose are both touching the detector
• the orbitomeatal line is running perpendicular to the detector
• petrous ridge is below orbits

Technical factors

• posteroanterior (PA) projection
• centring point
  • angled caudad around 15° to exit at the nasion 
• collimation
  • lateral to the skin margins
  • superior and inferior to the borders of the sinus cavities 
• orientation  
  • portrait 
• detector size
  • 24 cm x 30 cm 
• exposure
  • 70-80 kVp
  • 20 mAs
• SID
  • 100 cm
• grid
  • yes 

Image technical evaluation 

• no rotation evident via the symmetrical nature of the orbits 
• the innominate lines should be equidistant from the lateral borders of the orbits
• petrous rides projected in the lower third of the orbits 
• no tilting should be evident; an imaginary line through the petrous ridges should be horizontal

Practical points 

• always guarantee that the patient is not 'hunched' over when they are being examined. This can cause an artefact from the shoulders and the patient is more likely to be rotated; it is best to move the chair up close to the detector so they are sitting up straight for the X ray.
• remember, having one's head against an upright detector is uncomfortable, so try to have everything set up before you position the patient, to ensure patient comfort 
• constantly use a side marker and regularly place it PA. Skulls can get tricky with figuring out which side is which. Many venders tend to 'flip' images to make them appear AP