ChestAnkleFemurFootKneeTib-FibToesClavicleElbowFingerForearmHandHumerusShoulderThumbWristCervical Spine
Odontoid (Open Mouth)
Position the Patient
- Upright or supine
- Mouth open wide
- Raise or lower chin until teeth and skull base do not cover the dens
- Align head straight
- Keep mouth open without movement
Words That Work
“Keep your head straight and completely still while I adjust your chin so your teeth and the base of your skull line up. Open your mouth wide—like you’re at the dentist—and gently say ‘ah.’ This moves your tongue down and lets us see the top two bones of your neck through your open mouth. Keep your mouth open and don’t move until I tell you.”
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Odontoid (open mouth) positioning
Set Up the Shot
- Center here
- Central ray
- Through open mouth
- Include this in the field
- Collimation
- Odontoid region
- Set the distance
- SID
- 40"
- Check the technique
- Technique
- 70-85 kVp
- Follow facility protocols
Common Pitfalls
- •Teeth or skull base superimposing the dens
- •Mouth not open wide enough
- •Patient movement
Evaluate the Image
What should be visible?
- Dens
- C1 lateral masses
- C1–C2 joint space
Does the image pass?
- ✓Teeth and skull base not superimposing dens
- ✓Symmetrical lateral masses
- ✓C1–C2 joint space open
- ✓Sharp bony detail