Tests and diagnosisBy Mayo Clinic staff
During the physical exam, your doctor may try to pinpoint the cause of your pain by pressing directly on various places on your hips and buttocks. He or she may also move your legs into a variety of positions that will gently stress your sacroiliac joints.
An X-ray of your pelvis can reveal signs of damage to the sacroiliac joint. If ankylosing spondylitis is suspected, your doctor might recommend magnetic resonance imaging (MRI) — a test that uses radio waves and a strong magnetic field to produce very detailed cross-sectional images of both bone and soft tissues.
Because low back pain can be caused by so many different types of problems, your doctor may suggest using injections of anesthetics to help pinpoint the diagnosis. For example, if an injection of numbing medicine into your sacroiliac joint stops your pain, it's likely that the problem is in your sacroiliac joint. However, the numbing medicine can leak into nearby structures, and that can reduce the reliability of this test.
- Frontera WR, et al. Essentials of Physical Medicine and Rehabilitation: Musculoskeletal Disorders, Pain, and Rehabilitation. 2nd ed. Philadelphia, Pa.: Saunders Elsevier; 2008. http://www.mdconsult.com/das/book/body/208746819-6/0/1678/0.html. Accessed Nov. 20, 2012.
- Vora AJ, et al. Functional anatomy and pathophysiology of axial low back pain: Disc, posterior elements, sacroiliac joint and associated pain generators. Physical Medicine & Rehabilitation Clinics of North America. 2010;21:679.
- Anderson BC. Evaluation of the adult with hip pain. http://www.uptodate.com/index. Accessed Nov. 20, 2012.
- Canale ST, et al. Campbell's Operative Orthopaedics. 11th ed. Philadelphia, Pa.: Mosby Elsevier; 2008. http://www.mdconsult.com/das/book/body/208746819-4/0/1584/0.html. Accessed Nov. 20, 2012.
- Bope ET, et al. Conn's Current Therapy. Philadelphia, Pa.: Saunders Elsevier; 2012. http://www.mdconsult.com/books/about.do?eid=4-u1.0-B978-1-4377-0986-5..C2009-0-38984-9--TOP&isbn=978-1-4377-0986-5&about=true&uniqId=236797353-5. Accessed Nov. 20, 2012.
- Yu DT. Clinical manifestations of ankylosing spondylitis in adults. http://www.uptodate.com/index. Accessed Nov. 20, 2012.
- Imboden JB, et al. Current Rheumatology Diagnosis & Treatment. 2nd ed. New York, N.Y.: The McGraw-Hill Companies; 2007. http://www.accessmedicine.com/resourceTOC.aspx?resourceID=38. Accessed Nov. 21, 2012.
- Wu DT. Assessment and treatment of ankylosing spondylitis in adults. http://www.uptodate.com/index. Accessed Nov. 21, 2012.