Axial calcaneus X-ray positioning (prone)
An extra foot view, used when a routine one is not enough. The patient lies face down, the beam runs along the length of the part (axial), tilted 60° towards the feet, and the centring point is the heel.
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
Prone. Prone with the toes against the bucky.
Centring & collimation
Central ray
axialCentre: the heel.
Beam: axial, angled 60° toward-feet.
Collimate: the calcaneus
Distance, receptor & grid
| Setting | Value | Notes |
|---|---|---|
| SID | 100 cm | |
| Receptor | 18 × 24 cm | portrait |
| Placement | Erect (wall) bucky | Grid in |
| Angulation | 60° | toward-feet |
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 | 70 | 2 | 0.8 |
| S | 70 | 3.2 | 1.25 |
| M | 70 | 4 | 1.6 |
| L | 70 | 6.3 | 2.5 |
These start from a classic film-screen chart (70 kV, 32 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 calcaneus is shown axially.
- 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 |
|---|---|---|
| Foreshortened | Angle wrong | Check 60°. |
Common questions
- Where do you centre for a heel semiaxial (prone) X-ray?
- The centring point is the heel.
- What distance and beam angle does a heel semiaxial (prone) need?
- 100 cm from the tube to the receptor. The beam runs along the length of the part (axial), tilted 60° towards the feet.
- 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 heel semiaxial (prone)?
- Foreshortened. Usual cause: angle wrong. The fix: check 60°.
Try it in ScanFlo: the ScanFlo XR X-ray Room, coming soon, lets you set up a heel semiaxial (prone) in a 3D room and score your positioning. See ScanFlo XR →
Written by the ScanFlo team from everyday radiographic practice.