Facial Bones Lateral is a radiography positioning projection of the Skull. True lateral facial skeleton. SID 40". CR perpendicular to IR. The centering point is located zygoma, midway between the outer canthus and the EAM. Mid-sagittal plane parallel to IR. The central ray is perpendicular to IR (horizontal when the patient is erect or for a trauma lateral). Centered to the zygoma, midway between the outer canthus and the EAM. Image-quality criteria include facial bones and zygoma superimposed, sella turcica in profile (Merrill's). A sample technique is 80 kVp with DR 3.2 or CR 6.3 mAs, at an SID of 40 inches (102 cm).
Anatomy demonstrated
- Zygoma, with the facial bones superimposed.
- Nasal bone and maxillary sinus.
- Orbital rim, orbital cavity, and greater wing of sphenoid.
- Maxilla, maxillary process, and alveolar process.
- Sella turcica and orbital roofs.
- Mandible, including condyles and rami.
Patient preparation
- Trauma patient: use a supine horizontal beam lateral. Rule out cervical spine fracture, subluxation or dislocation before moving the head or neck.
- Verify patient identity.
- Remove glasses, earrings, hairpins, dentures.
- Position patient semiprone or erect with affected side against IR.
- Align mid-sagittal plane parallel to IR; interpupillary line perpendicular.
- IOML (infraorbitomeatal line) perpendicular to the front edge of the IR.
- Suspend respiration during exposure.
Position & centering point
Zygoma, midway between the outer canthus and the EAM. Mid-sagittal plane parallel to IR.
Central ray
Perpendicular to IR (horizontal when the patient is erect or for a trauma lateral). Centered to the zygoma, midway between the outer canthus and the EAM.
Exposure / technique
- kVp
- 80
- mAs
- DR 3.2 / CR 6.3
- SID
- 40" (102 cm)
- Notes
- Use small focal spot for sharper detail of facial bones. Sample technique: DR 3.2 / CR 6.3 mAs at 80 kVp, 40 in SID, for a 15 cm part. Adjust for your equipment.
kVp and mAs are sample values. Use caution when applying them in your department.
Image-quality criteria
- Facial bones and zygoma superimposed.
- Sella turcica in profile (Merrill's).
- Orbital cavity and orbital rim visible.
- Superimposed orbital roofs (no tilt).
- Superimposed mandibular rami (no rotation).
- Entire facial skeleton centered on IR with margin.
Common errors
- 1 Rotation: mandibular rami and greater sphenoid wings separate anteriorly and posteriorly.
- 2 Tilt: orbital roofs separate superiorly and inferiorly.
- 3 IOML not perpendicular to the front edge of the IR.
Clinical indications
- Evaluation of zygomatic arch for fractures.
- Nasal bone fracture assessment.
- Neoplastic or inflammatory processes of the facial bones, orbits, and mandible.
- Orbital cavity trauma or pathology.