Occipitomental (Waters) view X-ray positioning (sinuses and face)
One of the routine face & sinuses views. The patient sits, the beam passes back to front (PA), straight on to the receptor, and the centring point is the acanthion.
By the ScanFlo Editorial Team · Updated
In this section · X-ray positioning
- X-ray positioning guides
- Skull positioning
- Face & sinuses positioning
- Soft tissue neck positioning
- C-spine positioning
- Chest positioning
- Shoulder positioning
- Humerus positioning
- Elbow positioning
- Forearm positioning
- Wrist positioning
- Hand positioning
- T-spine positioning
- Abdomen positioning
- L-spine positioning
- Sacrum & SI joints positioning
- Pelvis positioning
- Hip positioning
- Femur positioning
- Knee positioning
- Tibia & fibula positioning
- Ankle positioning
- Foot positioning
X-ray positioning/Face & sinuses
Still being checked: a radiographer is reviewing this guide. If your department does it differently, follow your department.
Patient position
Sitting. Remove dentures, earrings, hair clips and anything in the hair. Seat the patient facing the bucky, mouth wide open, chin on the bucky, head tilted back so the orbitomeatal line is at 45°.
Centring & collimation
Central ray
PACentre: the acanthion.
Beam: PA, perpendicular to the receptor.
Collimate: frontal to maxillary sinuses
Distance, receptor & grid
| Setting | Value | Notes |
|---|---|---|
| SID | 100 cm | |
| Receptor | 18 × 24 cm | portrait |
| Placement | Erect (wall) bucky | Grid in |
| Angulation | None | Perpendicular to the receptor |
Marker & breathing
- Marker: R or L marker on the side nearest the detector
- Breathing: No breathing instruction needed.
Exposure by patient size
Treat these as a starting point. Your detector, your generator and the patient in front of you will all move the numbers.
| Patient size | kV | mAs (chart) | mAs (DR default) |
|---|---|---|---|
| XS | 80 | 8 | 3.2 |
| S | 80 | 12.5 | 5 |
| M | 80 | 16 | 6.3 |
| L | 80 | 25 | 10 |
These start from a classic film-screen chart (80 kV, 25 mAs at 140 cm) and are adjusted for a digital detector at 100 cm. The DR column is what ScanFlo's console suggests; each step up or down changes the mAs by about a quarter.
Image quality checklist
- Petrous ridges just below the floors of the maxillary sinuses.
- Sphenoid sinus seen through the open mouth.
- Fluid levels are horizontal (erect).
- The anatomical side marker is visible, correct and clear of the anatomy.
- Collimation borders are visible on all sides, no wider than the area requested.
Faults & how to fix them
| Fault | Cause | Fix |
|---|---|---|
| Petrous ridges over the maxillary sinuses | Head not tilted back enough | Raise the chin to 45°. |
Common questions
- Where do you centre for a sinuses and face semiaxial (occipitomental) X-ray?
- The centring point is the acanthion.
- What distance and beam angle does a sinuses and face semiaxial (occipitomental) need?
- 100 cm from the tube to the receptor. The beam passes back to front (PA), straight on to the receptor.
- What size receptor, and do you need a grid?
- Use an 18 × 24 cm receptor, portrait, in the wall bucky. A grid is needed.
- Where does the lead marker go?
- R or L marker on the side nearest the detector.
- What goes wrong most often on a sinuses and face semiaxial (occipitomental)?
- Petrous ridges over the maxillary sinuses. Usual cause: head not tilted back enough. The fix: raise the chin to 45°.
Try it in ScanFlo: the ScanFlo XR X-ray Room, coming soon, lets you set up a sinuses and face semiaxial (occipitomental) in a 3D room and score your positioning. See ScanFlo XR →
Written by the ScanFlo team from everyday radiographic practice.