Which listing produces anterior SI edema?

• A. PI
• B. AS
• C. EX
• D. IN

Answer: (D)

Edema location on the sacroiliac joint reflects where abnormal joint loading is occurring due to the pelvic misalignment. The IN listing corresponds to an anterior-inferior innominate orientation, which concentrates stress on the anterior aspect of the SI joint. That forward loading shows up as edema in the front of the joint on imaging, making this pattern the best match for anterior SI edema. Other patterns shift stress to other parts of the joint (for example, posterior loading would produce posterior edema), so they don’t explain the anterior edema as well.