Sinuses Lateral is a radiography positioning projection of the Skull. Upright lateral. CR horizontal. Demonstrates air-fluid levels. The centering point is located halfway between the outer canthus and the eam. ioml horizontal, ipl perpendicular.. The central ray is horizontal and perpendicular to ir. centered halfway between outer canthus and eam.. Image-quality criteria include all four paranasal sinus groups visible in lateral profile., sella turcica seen in profile.. Standard exposure ranges from 70 to 80 kVp, 15 to 25 mAs, at an SID of 40 inches (102 cm).
Anatomy demonstrated
- Frontal sinuses in profile.
- Ethmoid sinuses superimposed.
- Sphenoid sinus in profile, posterior to ethmoids.
- Maxillary sinuses superimposed.
- Sella turcica in lateral profile.
- Air-fluid levels when present.
Patient preparation
- Verify patient identity.
- Remove glasses, earrings, hairpins, and dentures.
- Position patient upright facing the IR.
- Place affected side against the receptor.
- IPL perpendicular to IR. IOML horizontal.
- MSP parallel to IR with no rotation or tilt.
- Suspend respiration during exposure.
Position & centering point
Halfway between the outer canthus and the EAM. IOML horizontal, IPL perpendicular.
Central ray
Horizontal and perpendicular to IR. Centered halfway between outer canthus and EAM.
Exposure / technique
- kVp
- 70–80
- mAs
- 15–25
- SID
- 40" (102 cm)
- Notes
- Upright required to show air-fluid levels. Horizontal beam essential. Grid required.
Image-quality criteria
- All four paranasal sinus groups visible in lateral profile.
- Sella turcica seen in profile.
- No rotation: superimposed mandibular rami.
- No tilt: superimposed orbital roofs.
- Air-fluid levels demonstrated when present.
- Sharp bony detail of the sinus walls.
Common errors / ARRT traps
- 1 Recumbent positioning hides air-fluid levels.
- 2 Vertical CR fails to show fluid-air interfaces.
- 3 Rotation of head: mandibular rami not superimposed.
- 4 Tilt of head: orbital roofs not superimposed.
Clinical indications
- Evaluation of sinusitis and detection of air-fluid levels.
- Sinus trauma workup.
- Pre-operative sinus surgery planning.
- Assessment of sphenoid and frontal sinus pathology.
Aligned to the 2025 ARRT Content Specifications.