Overview
AP oblique views of the sacroiliac joints profile the joint space and sacral ala for inflammatory and traumatic changes. The patient is rotated to place the SI joint of interest perpendicular to the detector. These views aid in detecting erosions sclerosis and joint space narrowing.
Technique
Rotate the patient approximately 25 to 30 degrees to the side of interest and center the detector to the sacroiliac joint. Use appropriate exposure and immobilize the patient to reduce motion. Obtain bilateral obliques for comparison when indicated.
Clinical Indications
SI joint obliques are indicated for suspected sacroiliitis trauma and pelvic pain. They help detect erosive changes and joint space irregularity. MRI provides superior soft tissue and early inflammatory detection when needed.
Image Assessment
Assess joint space symmetry erosions and subchondral sclerosis. Evaluate for sacral fractures and adjacent pelvic pathology. Report findings relevant to rheumatologic or orthopedic management.