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3 Tests to Tell You If Your Back Pain is Caused By SI

 3 Tests to Tell You If Your Back Pain is Caused By SI

Do you have lower back pain that might be caused by your sacroiliac (SI) joint? The sacroiliac joint (SIJ) is the cause of approximately 15-30% of all lower back pain cases. Even more eye-opening is that about 70-85% of the (western) population will experience low back pain in their lifetime! [1] While there are many factors taken into consideration when diagnosing SI dysfunction, there are some ways you can determine if you also have fallen victim to it. 

Hopefully, the discomfort hasn’t been significant or chronic enough to drive you here - it can be challenging to diagnose since some symptoms overlap with other hip and back conditions. So let’s not overlook the importance of seeing your primary care physician for proper testing and diagnosis. But with that said, let’s explore 3 tests to tell you if your back pain is caused by SI! 

3 Tests to Tell You If Your Back Pain is Caused By SI: FABER Test

The purpose of this test is to recreate any pain that exists in the SI area, lumbar spine, or hip.

FABER stands for: 



External Rotation

The FABER test is also known as Patrick’s test or figure-four test. This is when you lie flat and the examiner brings your hip joint (on the side of your SIJ pain) into the FABER position - one leg is bent at the knee and flat on the table, while the other leg is crossed so the ankle rests on the opposite knee. 

See the following short video for a visual: 

Your examiner typically presses down gently on the crossed knee while helping to stabilize the opposite hip. If you experience pain (or less range of motion afterward) in your SI joint or hip area, this could mean dysfunction or a related condition! 

3 Tests to Tell You If Your Back Pain is Caused By SI: Thigh Thrust

A thigh thrust is exactly what it sounds like. You lie flat while the affected side’s hip joint and knee are flexed to a 90-degree angle. Your examiner will apply pressure from the front and back - if you feel pain when force is applied, your test is positive. 

3 Tests to Tell You If Your Back Pain is Caused By SI: Gaenslen Test

  1. Lie on your back, close to the edge of the table
  2. Your affected side/leg will be hanging over the edge
  3. Your other side will have your knee flexed to your chest. 
  4. Firm pressure will be applied to your flexed knee
  5. (Simultaneously) Counterpressure will be applied to the knee of your hanging leg.
  6. If lower back pain is felt at this time, the test is considered positive.

3 Tests to Tell You If Your Back Pain is Caused By SI: Brief Anatomy

3 tests to tell you if your back pain is caused by SI

The sacroiliac joint connects the sacrum (the triangular bone at the bottom of your spine) to the ilium (the large pelvic bone). As noted by a study published in the Journal of Pain Research, "It acts as a shock absorber by dissipating the vertical forces of the spine and transmits these forces to the hips and lower extremities.” [1] 

Pain has been described by patients as sciatica-like, recurrent, and triggered by bending or twisting motions. The study goes on to explain that the root of SIJ pain can be traumatic or atraumatic. Examples of these include the following:


  • Motor vehicle accidents
  • Twisting injury
  • Falls

  • Atraumatic:

  • Infections
  • Cumulative injury
  • Multiple pregnancies
  • Inflammatory arthropathies

  • Some Risk Factors for SIJ Stress

  • Gait abnormalities
  • Prior lumbar fusion
  • Obesity
  • Lumbar spinal stenosis
  • Scoliosis and more… [1]

  • 3 Tests to Tell You If Your Back Pain is Caused By SI: Other Tests and Treatment

    There are other tests and procedures that can be done to diagnose SIJ pain, some of them include:

    • Distraction Test
    • Yeoman Test
    • Diagnostic imaging:
      • X-ray
      • MRI

    Often times, imaging is not performed unless the pain has been present for more than 6 weeks. Even then, evaluation and diagnosis typically involve an extensive physical exam, health history, and tests such as those noted above. SI dysfunction can be hard to diagnose because of the overlap with other conditions that also present as lower back or hip pain. Additionally, having a false positive result on a test is also a possibility. 

    Some examples of treatment for SI dysfunction include:

    • Exercise program/physical therapy
    • Manual manipulation therapy
    • Sacroiliac belts 
    • Pain injections
    • Fusion surgery [1]


    3 Tests To Tell You If Your Back Pain is Caused By SI: FAQ

    What is the one finger test for sacroiliac pain?

    The one finger test (AKA the Fortin finger test) is when the patient points with one finger to the location of their pain in the sacroiliac joint region. After a short period (5-10 minutes), they are asked again to point to where the pain is. A positive test result is if the patient points twice to the same area and if it is within close proximity (within 1 centimeter) to the posterior superior iliac spine. 

    What is the best way to diagnose SI joint dysfunction?

    After some exploration of the topic, there is not one simple diagnostic test for SI joint dysfunction. There are many related conditions and adjacent parts around the SI joint that can mirror SI dysfunction. For a successful diagnosis, your practitioner will likely use a combination of multiple tests/maneuvers and imaging if necessary.

    The study mentioned in this page reports, “While no single physical exams maneuver is diagnostic, a combination of specific findings and provocative tests can be essential in determining SIJ disorders… Typically, SIJ pain is diagnosed when at least three out of the five provocative maneuvers are positive.” [1]

    What is a physical exam for sacroiliitis?

    Some examples of a physical exam for sacroiliitis are those listed above on this page. 3 tests to tell if your back pain is caused by SI: FABER test, thigh thrust, and Gaenslen test. 

    What can be mistaken for SI joint dysfunction?

    This is where diagnosis requires accuracy because other conditions can also present as lower back or hip pain. Some examples include:

    • Lumbar spine disorders (spinal stenosis, disc herniations)
    • Hip disorders (hip osteoarthritis, bursitis)
    • Myofascial pain syndrome (trigger points around the SI joint)
    • Referred pain

    3 Tests to Tell You If Your Back Pain is Caused By SI: Conclusion

    I hope you were able to learn some awesome info about these 3 tests to tell if your back pain is caused by SI. After all, you can’t have success in treating your pain unless you have an accurate diagnosis… your chances for improvement may rely on the expertise of a healthcare professional. 

    As you move toward a pain-free way of life, the more you know, the more empowered you can be to make the best choices for yourself. By using a multidisciplinary approach and equipping yourself with a treatment plan that is unique to you, a better quality of life is just around the corner!


    [1] Buchanan, P., Vodapally, S., Lee, D., Hagedorn, J., Bovinet, C., Strand, N., Sayed, D., Deer, T. Successful diagnosis of sacroiliac joint dysfunction. Journal of Pain Research, 2021. 

    comment 1 comment

    Zyn calendar_today

    Thank you for these important information..

    I would like to know if there are psychosocial issues which can lead to SIJ pain?

    Leave a comment

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