An X-ray of both sacroiliac (SI) joints is a radiograph that visualizes the joints linking the sacrum and pelvis to assess alignment, joint space, fractures, degeneration, sacroiliitis or other inflammatory and infectious changes. Imaging both sides allows comparison. It’s quick, low‑dose, and may include multiple views; further CT or MRI is used if more detail about bone or soft tissue is needed.

The best plain radiographic view for the sacroiliac (SI) joint is a dedicated AP oblique projection with about 25–30° of rotation, which best opens the joint space and shows articular surfaces. A standard AP pelvis is complementary. For subtle disease, trauma, or suspected sacroiliitis, CT is more sensitive and provides the most definitive anatomic detail.

Position the patient supine with the pelvis centered on the table. Start with an AP pelvis including both sacroiliac joints. For dedicated SI views, obtain bilateral oblique projections by rotating the patient 25–30° away from the side of interest; center the central ray (CR) about 1 inch medial to the anterior superior iliac spine at the level of the SI joint. An AP axial SI (≈30° cephalad) may be added.

Inflammation of both sacroiliac joints is called bilateral sacroiliitis. It causes low back and buttock pain, stiffness, reduced spinal mobility, and sometimes radiating leg pain. Causes include inflammatory conditions (like axial spondyloarthritis), infection, trauma, or pregnancy-related stress. Diagnosis uses clinical exam, imaging, and blood tests; treatment includes anti-inflammatory drugs, physiotherapy, lifestyle measures, and, for some cases, biologic therapy.

Costs vary widely: in the U.S. a sacroiliac (SI) joint X‑ray typically costs about $100–$500 out‑of‑pocket depending on facility and region. In the U.K. it’s usually covered by public health services or about £30–£150 privately. In India retail rates often run ₹500–₹2,000. Final price depends on location, number of views, radiologist fees and whether insurance or public health covers imaging—check local providers.

Treatment begins with conservative care: activity modification, rest, heat/ice and NSAIDs for pain, plus physical therapy emphasizing pelvic stabilization and core strengthening. Supportive measures include SI belts and targeted mobilization or manipulation. For persistent pain, corticosteroid injections or radiofrequency ablation can reduce inflammation or interrupt pain signals. Rarely, surgical sacroiliac fusion is considered when conservative and interventional treatments fail.