South Wales Osteopathic Society

The sacro-iliac joints (SIJs for short) are two large joints, one on either side of the sacrum (the large triangular bone at the base of the spine) where it joins the right and left pelvic bones. These sturdy joints transmit weight from the back into the pelvis and have strong supporting ligaments. There is a small degree of movement in these joints, which lessens with age but increases during pregnancy.

SIJ trouble can include strains, inflammation (as in ankylosing spondylitis), arthritis, locking and hypermobility (in which the ligaments are lax and let the joint move too much). Problems can arise suddenly, for example by excessive leverages being placed on the joint through the lower limbs, or gradually by repeated minor trauma. Lack of mobility in the spinal joints above  can cause adverse loads on the SIJs. The SIJs are particularly vulnerable in pregnancy, when hormones loosen the ligaments.

At the base of the spine on either side are two dimples that overlie the PSIS (posterior superior iliac spine), a bony prominence on the pelvis that is an anchor point for the low back muscles, They are tender and painful in many – probably most – back conditions, regardless of  what condition it is,Sometimes patients who know a little bit of anatomy think that pain or tenderness here indicates a sacro-iliac joint problem. It doesn’t , The SIJs actually lie deeper and extend further down.

Even pain felt over the area of the SIJs may in fact be referred from the lumbo-sacral joints just above, or even be from the dorso-lumbar joints (between the mid and low back) via the cluneal nerves.

Osteopaths diagnose SIJ problems from the case history and clinical signs.  Painful SIJs are made worse by characteristic activities, such as crossing the legs, climbing stairs, and turning.Assessment of the pelvis may reveal assymmetry of boney landmarks, alterations of joint mobility, or pain on tests that load the SIJs.

Case Study Susan was a keen golfer but she was finding increasing pain on the right side of the pelvis and low back each time she played. She had previously seen an osteopath about another complaint, so went along to see what they thought. They found a  hypermobile (overmobile) right sacro-ilac joint.

 The osteopath said that although the right SIJ was too mobile, the left was not flexible enough. On top of thast, the dorso-lumbar area of the spine, which normally rotates well, was limited in its mobility. Both these factors were placing more stress on the right SIJ when Susan turned and walked.