Sacroiliac Joint Dysfunction - Causes and Treatment

The Sacroiliac (SI) joint is the joint where the spine (the sacrum) attaches to the pelvis (the ileum). SI joint dysfunction is caused by problems at these joints leading to pain and sometimes instability.

The sacroiliac joint is part of the pelvic girdle. This girdle is made up of the two half of your pelvis, your sacrum and the joints where these bones touch - the two sacroiliac joints on either side at the back, and the symphysis pubis joint at the front.


diagram showing the pelvic grrdle with the sacroiliac joints and pubic symphysis highlighted

Pelvic Girdle showing the sacroiliac joints and the pubic symphysis

These three bones provide a very strong and stable platform which supports your body weight. The sacroiliac joints in particular are well designed to resist downward pressure. They are very large, ovalish, irregular joints. They are rarely the same on both sides - asymmetry is normal. The irregularity of the joint makes it very firm and stable and there is very little movement that takes place here as a result.

sacrum showing the sacroiliac joint surface

Sacrum showing the large irregular sacroiliac joint surface

The amount and the importance of this small movement is hotly debated. However, I have seen enough people with this problem to know that if this small amount of movement is lost or becomes too great then problems can occur leading to sacroiliac joint pain.

Sacroiliac joint dysfunction can affect anyone at all ages but is mostly caused by the following:.

  • Very commonly it affects women who are pregnant or have recently had a baby
  • Sometimes it is caused by trauma such as a fall onto the bottom
  • Rarely it is caused by inflammation of the joints i.e. sacroilitis or ankylosing spondylitis
  • Age changes or osteoarthritis .

The most common of all these is pregnancy. This is due to several things:

  • The ligaments supporting the sacroiliac joint become deliberately softened by the body's hormones in order to allow the joints to move apart. This can lead to pain.

  • The sacroiliac joints endure additional physical stresses and strains during pregnancy. The pelvis has to widen a lot to allow the baby into the world. The movement takes place at these joints.

  • Sacroiliac joint problems are rarely serious.

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What tests are useful to diagnose the problem?

sacroiliac joint
X-ray showing the sacroiliac Joints

X-rays and scans are important if an inflammatory cause of the problem is suspected. They may show up some characteristic changes in the joint such as sacroilitis which is a type of inflammation seen with ankylosing spondylitis.

X-rays may also show any osteoarthritis in the joints- these changes are also called sacroiliac joint arthropathy

If instability is suspected X-rays taken standing on one leg may be suggested.

However, like most lower back pain tests, more often then not scans and X-Rays are normal or just show the usual age changes. .


X-Rays are unsuitable for pregnant women.

However, to diagnose sacroiliac joint pain you don't really need anything that complicated to be honest.

One of the biggest problems with diagnosing this is separating it off from regular non-specific back pain. There are certain physical tests that a clinician can use to work out if the problem is coming from the lower back or the sacroiliac joint. These tests have been recommended in the newest clinical guidelines to help form a diagnosis (Vleeming et al. 2008). Note - several of these tests have to be positive for you to be confident this is the problem.

Thigh Thrust Test

thigh thrust test

Gaenslens test

gaenslens Test

Fabers Test

fabers test

These are accompanied by a modified Trendeleneberg test and some tests where the clinician feels or palpates the ligaments and joints. Unfortunately, you can't do these to yourself - so you need to go and see someone who can and who will be able to diagnose the problem for you.

What is the best treatment for sacroiliac joint pain?

This depends on the type of problem and if it is caused by pregnancy:.

  • Stabilising exercises are commonly suggested if the joints are too mobile or there is a suspicion of instability
  • Joint manipulation may be helpful if the joints are stiff.
  • Pain relieving treatments such as medication, massage and heat may help.
  • Acupuncture and/or TENS may also help ease pain (not for pregnant women).
  • Corsets and supports are offered during pregnancy.
  • Pain relieving injections may be offered and surgery as a very last resort if the joint is very unstable.

A medical or physiotherapy assessment is essential to identify the type of sacroiliac problem and make the right suggestions for managing it.


Vleeming, A. et al., 2008. European guidelines for the diagnosis and treatment of pelvic girdle pain. European spine journal: official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society.

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July 29, 2017




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