Understanding sacroiliac joint pain first starts with understanding where the joint is located.

The sacroiliac joints are located at the base of the spine, one on the left and one on the right. The joint is formed between the sacrum (the flat bone that you can feel at the base of the spine), and the ilium (the large broad bone that forms the upper part of the pelvis). It is most often referred to as the SIJ (sacroiliac joint). The SIJ is a stable joint with a relatively small amount of movement. Its main function is to transfer forces between the spine and the legs and acts as a shock absorber. The joint is mostly stabilized by numerous strong ligaments.
Why does SIJ pain occur?
SIJ pain can occur at any age and can impact both men and women. Sacroiliac joint pain may occur for various reasons:
- Often occurs in pregnant and post-partum women due to the increase in hormones that allowed the pelvis to be more flexible in preparation for birth.
- Arthritis can develop in the SIJ like other joints in the body
- Trauma caused during an automobile accident (often as a person has the leg pressing hard on the brake and the force transmits into the pelvis asymmetrically)
- Obesity can place more stress through the SIJ
- Leg length discrepancy and scoliosis can increase the force going through your SIJ due to an altered walking pattern.
- Repetitive strain from contact sports and labour-intensive jobs
Symptoms of SIJ involvement
What are the symptoms of SIJ dysfunction?
- Pain into the low back and buttock
- Pain can be on one side, or both
- Sciatica-like pain radiating from the back and down into the back of the leg
- Pain with prolonged sitting or standing
- Difficulty transitioning from sitting to standing, or lying to sitting
- Stiffness and reduced range of motion in the lower back
Can physiotherapy help if I have sacroiliac joint pain?
Physiotherapists can work with you to determine if you are putting strain through your SIJ during your work or leisure activities. Often making small changes in your daily habits can make large difference in your pain. For example, sitting with legs crossed (especially when it is predominantly one sided), or standing with your weight continually shifted to one side, or even sleeping on a mattress with little support can increase the tension through the SIJ and potentially lead to pain. Physiotherapists can also offer hands-on manual therapy to work on the joint and the muscles that impact pelvic stability.