Oblique cervical spine X-ray positioning
An extra C-spine view, used when a routine one is not enough. The patient stands turned at an angle, the beam passes at an oblique angle, straight on to the receptor, and the centring point is C4.
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, erect. Seat the patient turned 45° to the bucky; take both sides. Not for children.
Centring & collimation
Central ray
obliqueCentre: C4.
Beam: oblique, perpendicular to the receptor.
Collimate: base of skull to T1
Distance, receptor & grid
| Setting | Value | Notes |
|---|---|---|
| SID | 150 cm | |
| Receptor | 18 × 24 cm | portrait |
| Placement | Erect (wall) bucky | Grid in |
| Angulation | None | Perpendicular to the receptor |
Marker & breathing
- Marker: R and L markers
- Breathing: Suspend respiration.
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 | 8 | 3.2 |
| S | 70 | 12.5 | 5 |
| M | 70 | 16 | 6.3 |
| L | 70 | 25 | 10 |
These start from a classic film-screen chart (70 kV, 12.5 mAs at 140 cm) and are adjusted for a digital detector at 150 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
- Intervertebral foramina shown open.
- Both obliques taken.
- 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 |
|---|---|---|
| Foramina closed | Rotation not 45° | Rotate to 45°. |
Common questions
- Where do you centre for a cervical spine oblique X-ray?
- The centring point is C4.
- What distance and beam angle does a cervical spine oblique need?
- 150 cm from the tube to the receptor. The beam passes at an oblique angle, 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.
- What should the patient do with their breathing?
- Ask them to stop breathing for the moment of the exposure.
- What goes wrong most often on a cervical spine oblique?
- Foramina closed. Usual cause: rotation not 45°. The fix: rotate to 45°.
Try it in ScanFlo: the ScanFlo XR X-ray Room, coming soon, lets you set up a cervical spine oblique in a 3D room and score your positioning. See ScanFlo XR →
Written by the ScanFlo team from everyday radiographic practice.