PA oblique sternum X-ray positioning
An extra chest view, used when a routine one is not enough. The patient lies face down, turned at an angle, the beam passes back to front (PA), straight on to the receptor, and the centring point is the mid-sternum.
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
Still being checked: a radiographer is reviewing this guide. If your department does it differently, follow your department.
Patient position
Oblique, prone. Lay the patient prone, rotated 15–20° to project the sternum over the heart shadow.
Centring & collimation
Central ray
PACentre: the mid-sternum.
Beam: PA, perpendicular to the receptor.
Collimate: the sternum only
Distance, receptor & grid
| Setting | Value | Notes |
|---|---|---|
| SID | 100 cm | |
| Receptor | 24 × 30 cm | portrait |
| Placement | Table bucky | Grid in |
| Angulation | None | Perpendicular to the receptor |
Marker & breathing
- Marker: R or L marker on the side nearest the detector
- Breathing: Quiet breathing.
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 | 70 | 6.3 | 6.3 |
| S | 70 | 10 | 10 |
| M | 70 | 12.5 | 12.5 |
| L | 70 | 20 | 20 |
These start from a classic film-screen chart (70 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
- The sternum is projected over the heart, clear of the spine.
- Lung markings are blurred by quiet breathing.
- 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 |
|---|---|---|
| Sternum over the spine | Too little rotation | Increase the obliquity. |
Common questions
- Where do you centre for a sternum oblique PA X-ray?
- The centring point is the mid-sternum.
- What distance and beam angle does a sternum oblique PA 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 a 24 × 30 cm receptor, portrait, in the table bucky. A grid is needed.
- What should the patient do with their breathing?
- They can keep breathing gently; no breath-hold is needed.
- What goes wrong most often on a sternum oblique PA?
- Sternum over the spine. Usual cause: too little rotation. The fix: increase the obliquity.
Try it in ScanFlo: the ScanFlo XR X-ray Room, coming soon, lets you set up a sternum oblique pa in a 3D room and score your positioning. See ScanFlo XR →
Written by the ScanFlo team from everyday radiographic practice.