SI Joints AP
Position the Patient
- Supine
- Legs extended
- Mid-sagittal plane centered to IR
- Pelvis straight with no rotation
Words That Work
“Lie flat on your back with your legs straight and your toes pointing up. Keep your hips level and centered without rolling to either side. I’ll angle the X-ray beam slightly upward to help open both sacroiliac joints. Breathe all the way out, hold it, and stay still.”
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AP SI joints - room setup
Set Up the Shot
- Center here
- Central ray
- Midway between ASIS and pubic symphysis; 15–20° cephalic
- Include this in the field
- Collimation
- SI joint region
- Set the distance
- SID
- 40"
- Check the technique
- Technique
- 75-85 kVp
- Follow facility protocols
Common Pitfalls
- •SI joints not open (incorrect CR angle)
- •Asymmetrical pelvis
- •Rotation
Evaluate the Image
What should be visible?
- Bilateral SI joints
- Sacrum
- Iliac wings
Does the image pass?
- ✓SI joints open
- ✓No rotation (symmetrical pelvis)