An X‑ray of both sacroiliac (SI) joints is obtained with the patient supine, pelvis centered and legs extended. A frontal (AP) pelvis or dedicated AP SI view centers the X‑ray beam at the midline between the anterior superior iliac spines and pubic symphysis. Oblique views (about 15–30° rotation) are often taken to better open each SI joint for clearer assessment of alignment, sclerosis, or erosion.

AP (anteroposterior) and Lat (lateral) are common X‑ray projections. AP means the X‑ray beam enters the front (anterior) and exits the back (posterior) of the body; it’s often used when patients cannot stand and can magnify anterior structures. Lateral views pass from one side to the other, giving a right‑angle side image that helps localize lesions and separate overlapping anatomy.

The best plain radiographic view for the sacroiliac (SI) joint is an oblique projection (roughly 20–30°) of each joint, which profiles the joint space and cortical margins. For detecting early inflammatory or subtle marrow changes, MRI—especially STIR or fat‑suppressed T2 sequences—provides superior sensitivity and is preferred when radiographs are inconclusive.

Costs vary by country and facility. In the US an SI‑joint (pelvic/sacroiliac) X‑ray typically runs about $50–$400 out‑of‑pocket; with insurance your copay or negotiated rate is often lower. In the UK the NHS covers it for eligible patients; private imaging is roughly £40–£150. In India expect roughly ₹200–₹1,000. Additional fees for radiologist reports or extra views may apply.

An X-ray can detect some sacroiliac (SI) joint problems — especially chronic bony changes like joint-space narrowing, sclerosis, erosions, or fusion from osteoarthritis or longstanding inflammatory disease. However, X-rays often miss early inflammatory changes, subtle erosions, or soft-tissue/ligament dysfunction. CT gives better bony detail and MRI is most sensitive for early inflammation and bone marrow edema, so further imaging is often needed.

Yes—gentle, regular walking is often helpful for sacroiliac (SI) joint pain because it promotes blood flow, reduces stiffness, and engages core and gluteal muscles that support the pelvis. Avoid long hikes, uneven terrain or pain‑provoking speeds; stop if pain worsens. Combine walking with targeted stretches and strengthening, use supportive footwear, and see a clinician if pain is severe, worsening, or persistent.