Facial Bones PA Axial (Caldwell) is a radiography positioning projection of the Skull. Caldwell method. Orbital rims, maxillae, facial bones. CR 15° caudad. The centering point is located CR exits at nasion. Forehead and nose against IR. The central ray is CR angled 15° caudad. Exits at nasion. Image-quality criteria include frontal sinuses projected clearly above orbital rims, anterior ethmoid air cells lateral to each nasal bone, below the frontal sinuses. A sample technique is 85 kVp with DR 7.1 or CR 14 mAs, at an SID of 40 inches (102 cm).
Anatomy demonstrated
- Frontal sinuses above orbital rims.
- Anterior ethmoid air cells, lateral to each nasal bone.
- Orbital rims and orbital cavities bilaterally.
- Nasal bones and nasal septum.
- Maxillae and anterior nasal spine.
- Zygomatic bones and zygomatic processes.
Patient preparation
- Trauma patient: rule out cervical spine fracture, subluxation or dislocation before moving or manipulating the head or neck.
- Verify patient identity.
- Remove glasses, earrings, dentures, hairpins.
- Position patient prone or upright.
- Forehead and nose against IR; OML perpendicular to IR.
- MSP perpendicular to the midline of the grid, with no head rotation or tilt.
- Suspend respiration during exposure.
Position & centering point
CR exits at nasion. Forehead and nose against IR.
Central ray
CR angled 15° caudad. Exits at nasion.
Exposure / technique
- kVp
- 85
- mAs
- DR 7.1 / CR 14
- SID
- 40" (102 cm)
- Notes
- 15 degrees caudad projects the petrous ridges into the lower third of the orbits; for the orbital floors, use 30 degrees caudad to project them below the inferior orbital margins. For a sinus exam, the patient must be erect with a horizontal CR and the OML 15 degrees from horizontal (Bontrager); ARRT lists the sinus Caldwell as horizontal beam in both the 2022 and 2027 outlines. Sample technique: DR 7.1 / CR 14 mAs at 85 kVp, 40 in SID, for a 20 cm part. Adjust for your equipment.
kVp and mAs are sample values. Use caution when applying them in your department.
Image-quality criteria
- Frontal sinuses projected clearly above orbital rims.
- Anterior ethmoid air cells lateral to each nasal bone, below the frontal sinuses.
- Petrous ridges projected into the lower third of the orbits.
- Entire orbits and facial bones (Merrill's).
- No rotation: equal distance from midline to orbit.
- No rotation or tilt: superior orbital fissures symmetric.
- Nasal septum, zygomatic bones, and anterior nasal spine shown.
Common errors
- 1 30 degrees caudad for a routine view: ridges fall below the IOM; keep it for orbital floors.
- 2 Rotation: unequal distance from midlateral orbital margin to lateral cranial cortex.
- 3 Tilt: MSP not perpendicular to the midline of the grid.
Clinical indications
- Fractures and neoplastic or inflammatory processes of the facial bones.
- Sinus exam (sinusitis, polyps, cysts): done erect with a horizontal CR, not this setup.
- Trauma evaluation of facial and orbital bones.