Thumb AP
Position the Patient
- Seated at table
- Place hand on IR
- Turn hand so thumb is AP
- (rotate hand internally)
- Keep thumb straight
Words That Work
“Turn your whole hand inward until the thumbnail side of your thumb rests flat against the plate—like you’re hiding your thumbnail from me. Keep your thumb straight and hold still.”
AP thumb positioning
Set Up the Shot
- Center here
- Central ray
- MCP joint
- Include this in the field
- Collimation
- Entire thumb and full metacarpal
- Set the distance
- SID
- 40"
- Check the technique
- Technique
- 55-60 kVp
- Follow facility protocols
Common Pitfalls
- •Thumb not straight
- •Rotation
- •Joints not open
Evaluate the Image
What should be visible?
- Entire thumb
- IP and MCP joints
- Full metacarpal
Does the image pass?
- ✓Thumb straight
- ✓No rotation (symmetric appearance of shafts)
- ✓Joints open
- ✓Entire thumb and metacarpal included