SIJ pain – why it happens & how to relieve pain

SIJ pain presents as a sharp stabbing pain into the buttock area without referred pain into legs, pins & needles or numbness.

The pain is typically felt on either side of the sacrum, rather than in the centre.

Aggravating activities usually involve loading on one leg (for example, stepping down off a curb or gutter) or bending one leg up (for example, bending to do up a shoelace).

The Sacro-Iliac joint (SIJ) is a very rigid joint with only 2-3 degrees of normal movement.

Pain arises when the joint stiffens after excessive loading with some impact (like carrying heavy boxes downstairs when moving house) or if the joint develops too much movement (like in pregnancy when hormones relax the ligaments supporting the joint).

There are also inflammatory conditions that can affect SIJ and cause symptoms without loading or hormonal changes.

Determining which form of SIJ dysfunction is present is vital as the fixes for different causes are completely different.

Utilising the wrong treatment approach will worsen the pain. There’s more about that in the next section.


  • SIJ pain typically falls into three categories
    • Hypomobile – stiffness caused by reduced daily activity levels (eg. Bed bound with illness) or a temporary inflammatory response to overload (eg. Several heavy days of gardening)
    • Hypermobile – additional movement caused by hormonal changes (eg. Pregnancy) or reduced muscle support for the joint (eg. Gluteal muscle injury reducing the effectiveness of its joint stabilisation function)
    • Systemic Inflammatory Disease – SIJ on both sides of the sacrum can react due to a systemic inflammatory pathology (eg. Ankylosing Spondylitis). This is often coupled with joint pains in other areas of the body
  • Identifying whether the SIJ pain improves with more movement or more stability is essential in figuring out the best management approach.
    • For an SIJ that has become stiff will cause more pain if a supportive belt is applied, further reducing its available movement
  • The most common treatment options for each type of SIJ dysfunction are:
    • Hypomobile
      • Manual therapy – hands on treatment to move the joint
      • Light exercise – simply going for a walk can feel painful at first but improves with gentle movement and time
    • Hypermobile
      • SIJ belt – a compressive belt that sits over the hips and pelvis, it’s very effective for immediate relief and is favoured during pregnancy
      • Gluteal exercises – improving muscle support for the joint is essential as a medium term solution and is often coupled with a faster fix such as the SIJ belt
    • Inflammatory conditions typically uses a combination of approaches, including


  • SIJ pain cannot refer pain into the legs or up into the lower back
    • The pain always remains localised around the affected joint
    • One early study found SIJ pain referring down the leg, however that study was flawed due to the “localised” testing injections affecting structures away from the intended target
  • The SI joint cannot slip or rotate without massive forces (eg. high speed car accident or fall from great height with significant pelvic damage)
    • A diagnosis of an “upslip”, “counternutation”, etc has no merit or basis whatsoever
    • The “excessive” movement in hypermobility equates to a fraction of a millimetre and is not detectable by palpating the joint thru the soft tissue structures
  • Relief from SIJ pain should be fairly rapid, not a gradual costly process of regular treatments over weeks and months
    • If you’re trying a SIJ belt or manual therapy, you should notice immediate relief of a majority of your pain
    • For pregnant women, you’ll get immediate relief but this doesn’t mean it’ll resolve the condition
      • The aim is to manage the pain to preserve function


  • Lower back pain – can refer pain across the SIJ
  • Hip osteoarthritis – it can cause similar pain and often coexists with SIJ dysfunction
  • Hip labral tear – this often has inconsistent aggravating activities – it’ll sometimes hurt on stairs and other times, it’s pain free
  • Sacral stress fracture – causes a more persistent pain, even at rest
  • Deep hip muscle overload – muscle pain from the deeper muscles, just adjacent to the SIJ. They usually don’t cause sharp pain

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