A plausible, alternate hypothesis for patient reports of asymmetries within the pelvis

The existence of positional faults of the intra-pelvic joints (sacroiliac joints, symphysis pubis) resulting in pelvic asymmetries remains a hotly debated topic amongst clinicians and researchers in the field of pelvic girdle pain. Check Chapter 46 in the latest edition of Grieve’s Modern Musculoskeletal Physiotherapy for some different takes on the topic.

We have long been critical of the existence, and by extension relevance, of pelvic asymmetries in pelvic girdle pain. This criticism extends from a number of directions. For one, the most valid investigation of the existence of intra-pelvic positional faults by Tullberg (1) failed to identify their existence. On another front, we have observed negative patient attributes based around their beliefs of pelvic asymmetries. This includes development of fear, avoidance and dependency on passive treatments. Thirdly, we have heard many clinicians’ stories of struggling with the concept of positional faults resulting in them loosing their clinical confidence.

Yet, patients with pelvic girdle pain often report a sensation of asymmetry within their pelvis.

So if not positional faults of the intra-pelvic joints, what might underlie patient reports of pelvic asymmetry? We have just published research that points to a plausible, alternate hypothesis for these subjective reports from patients (2).

Similar reports of bodily asymmetry come from patient with LBP, where they report a feeling of displacement of their vertebrae. Lorimer Moseley (3) nicely depicted this by having subjects with LBP draw their vertebrae. Subjects with unilateral LBP drew deviations of their vertebrae towards the side of pain. Lorimer reported on a relationship between the drawings and changes in two-point discrimination threshold. This type of change in body representation within the brain has now become an accepted potential mechanism in chronic pain presentations. Subsequently, Ben Wand (4) developed the Fremantle Back Awareness Questionnaire as a subjective measurement tool to investigate changes in body perception in LBP subjects such as those reported by Lorimer. In our recent study (2), we found that subjects with higher levels of disability related to chronic lumbo-pelvic pain (that originally developed during or shortly after pregnancy) had greater levels of altered body perception as assessed with Ben’s questionnaire. We did not ask the participants in this study if they felt their pelvis was out of alignment. Further investigation of this potential mechanism in subjects specifically reporting pelvic asymmetry is a logical next step.

There was also some correlation between altered body perception and kinesiophobia in our study (r=0.43, p=0.037) (2). While again speculative, this might indicate a pathway from altered body perception to fear and avoidance, reported by many patients with chronic pelvic girdle pain.

As usual, more research is needed to further investigate the relationships identified in our study. Never the less, there is indication that clinicians might consider altered body perception as a contributing factor in disabling, chronic pelvic girdle pain. Assessment in the clinic may include use of validated measures such as Ben’s questionnaire. Visualisation activities like ‘body scanning’ and ‘mirror feedback’ may provide useful information to clinicians on how patients perceive their body. We are not aware of the use of any published studies using two-point discrimination specifically in subjects with pelvic girdle pain, but this might have utility also. Additionally, providing patients with a plausibly alternate theory for their perception of positional faults may be a powerful management tool.

I would like to acknowledge the co-authors on the recent paper we published in Manual Therapy; Peter O’Sullivan, Ali Lutz, Ben Wand and Judith Thompson.

About Darren Beales

Darren Beales Curtin UniDarren is a Specialist Musculoskeletal Physiotherapist at Pain Options and a Senior Research Fellow at Curtin University.


  1. Tullberg T, Blomberg S, Branth B, Johnsson R. Manipulation does not alter the position of the sacroiliac joint. A roentgen stereophotogrammetric analysis. Spine. 1998;23(10):1124-8; discussion 9.
  2. Beales D, Lutz A, Thompson J, Wand BM, O’Sullivan P. Disturbed body perception, reduced sleep, and kinesiophobia in subjects with pregnancy-related persistent lumbopelvic pain and moderate levels of disability: An exploratory study. Man Ther. 2016;21:69-75.
  3. Moseley GL. I can’t find it! Distorted body image and tactile dysfunction in patients with chronic back pain. Pain. 2008;140(1):239-43.
  4. Wand BM, James M, Abbaszadeh S, George PJ, Formby PM, Smith AJ, et al. Assessing self-perception in patients with chronic low back pain: Development of a back-specific body-perception questionnaire. Journal of back and musculoskeletal rehabilitation. 2014;27(4):463-73.

Commissioning Editor: Ben Wand;  Associate Editor: Jane Chalmers


  1. Hi Filipe

    Thanks for your comments. We believe the evidence points towards a perceptual occurrence for the vast majority. This evidence relates to putting little ball bearings in the pelvis and getting a 3D representation via X-ray, an extremely accurate true gold standard for joint position. The one study that has done this specifically for positional faults in the pelvis found that they do not exist. Still, there are arguments about this as highlighted in the post.

    Many people report exactly what you are stating, because that is how it feels (without health care practitioner input). You are describing what you are feeling, which is highly valid and acknowledged. What you are describing may result for altered muscle condition, or as we propose for some people perceptual changes in body awareness.

    Usually with a thorough evidence informed examination, contributing factors to your pain can be identified. Frequently these are modifiable in a positive way. But positional faults within the pelvis are not one of them as far as we are concerned.


  2. Hi Darren

    Thanks for these insights. Over the past year I have been feeling a sense of pelvic misalignment, and often hear the bones moving against each other when walking. I find it difficult to have a comfortable position in bed at times. Nobody told me this. These are my own words. I dont feel pain all the time, just sometimes, but usually feel discomfort. I wonder whether pelvic missalignment is really just perceptual or a real problem that therapists face difficulty in diagnosising. Whilst I agree therapist feedback may reinforce one’s beliefs of structural fragility (and that some people are more vulnerable to this), I find through my experience that pelvis missalignment seems a reality in my case. I have never seen a therapist for this, so the therapist feedback theory does not apply (although I might agree with it once feedback is given). Thanks

  3. Michael Ward says

    Hi Kal 🙂 your comment was general / blanket and your personal anecdote belies the your suggestion that you are restricting your comments to the pelvis being out. Already you have simultaneously expanded and limited the point of discussion. Pelvis – chronic pain – meniscus. I brought up meniscus because it is a common reported sensation but also correlates with a structural fault. Cheers BTW I agree with you re terminology – we describe things with the vocab and knowledge that we are equipped with.

  4. Michael Ward says

    Gee Kal, I’m not so sure about the ignoring advice – firstly I guess there are the Darwin awards to suggest otherwise. Despite the apocryphal advances in McKenzie therapy (serendipitous extension therapy) or the progression for ACL reconstructions from patients self progressing out of casts or braces, I can think of quite a few bad results from ignored instructions following rotator cuff surgery, hand surgery early return to play (even though some people beat the odds). Besides where does your advice to ignore advice leave your role in rehab?.

    However, I agree – Darren, thanks for an interesting article – I suspect it is more about the language / vocab that is given and expected to be accepted than the actual sensory characterisitics of pelvic girdle pains. Your hypothesis might be more applicable to other regions such as meniscal injuries in the knee; shoulder; and some spinal presentations.

    Kal Fried Reply:

    Hello Michael,
    The first bad decision in many is to have the surgery in the first place if their problem is pain.
    Also I can’t actually recall a Darwin award that involved someone ignoring advice about their back and pelvic alignment.
    PS: I am actually talking specifically about responses to comments such as ‘your pelvis is out’, ‘your chronic pain is due to a slipped disc / torn meniscus etc, etc, etc’.

  5. Consider that a (facebook-equivalent) big TICK.

    Love your quote. Reminds me of quote from Marcus Garvey, a negro activist – “The pen is mightier than the sword, but the tongue is mightier than them both put together.”
    And he never even heard the word – ‘nocebo’.

  6. Hi Kal,
    The only ones that do present with the thought that their pelvis is out of alignement is because they have been given that opinion by their therapist.
    More damage done by the word than the scalpel….

  7. Hi Darren – great work!
    Do patients present initially saying that they have a pelvic alignment problem?
    Not likely.
    They present with pain.
    We tell them that we think they have things “out”.
    This is just another common example of a ‘pain catch 22’ situation and the profound influence of subjective and speculative msk comments.
    ie: managing pain by scaring people with our opinions of their ‘flawed’ structure. And ignoring the brain’s pain equation of danger versus safety.

    PS: I would love to see a study on the outcomes of patients who actually ignore what they are told by various msk / orth experts.
    I suspect they would uniformly do very well.
    Anecdotal eg: me when I had a MRI C spine 8 years ago that looked horrible, scared the crap out of me, and then I simply forgot about it and got on with my (cycling 200km per week etc) life.
    Not to mention my lumbar spine, knees etc ….

    Darren Beales Reply:

    Thanks Kal
    Agree that beliefs such as these frequently perpetuate from health care practitioners. In our section in Grieves Modern Musculoskeletal Physiotherapy we have a table indicating helpful and harmful statement specific around this language that is common in pelvic girdle pain.
    Look forward to seeing you publish that study!

    Monica Thomas Reply:

    As a physiotherapy patient, I can actually see in the mirror (yes – and without turning or twisting) that my left ASIS is lower than my right ASIS and that my left SI joint is higher than my right SI joint. And, when my sacrum rotates, it is clearly visible – as seen in photos my husband has taken (in order to show me). My PT does not have to tell me – I can feel and see the evidence. Once I went in and told my PT that I was having pain in my lumbar spine which felt different, as if something were “poking” the left side of my lumbar spine. It was a new experience/sensation. He used manual therapy to address the issue. Only after this same scenario occurred four times did I ask him about the “poking” sensation. He explained/showed on a skeleton how facets can rotate and what he did in response to what I reported and what he actually found upon examination. And, for the record, he and I both know (other medical professionals agree – I’ve had extensive exams/tests/scans, etc. that central sensitization is a key factor. Who told me about central sensitization? No one. I did the research – read Woof, Clauw and many others. Did I self-diagnose? Maybe. In fact, my PT was resistant to this possibility for well over a year (probably more). There is no longer any question, however. Just my two cents worth.

    Kal Fried Reply:

    Hi Monica,

    Your body is only capable of providing nociceptive input to pain. How it is then processed is idiosyncratic and contextually vulnerable. I have had many athletes competing at high and weekend levels who have had a great variety of biomechanical variations. The relationship between such changes and pain is extraordinarily tenuous and the neuroplasticity side of things (of which sensitisation is a recognised outcome) predominates in significance much greater than facet joint pressures etc.

    There are many ‘catch 22s’ in pain ie: believing that your body is flawed and fragile will actually perpetuate pain via the brain’s ‘danger versus safety’ equation.

    That is not to say that you should ignore your structure completely; it just means that it is not as important as you think in chronic pain.
    The human body is an extraordinary healing and adapting machine, but in order for that to happen both body and brain / neuroplasticity have to be going in the same direction.

    Genuinely hope you find the path to your optimal outcome which is very difficult these days and is more often counter-intuitive ie: ignoring negative concepts and simply exercising, normalising as much as possible etc and regaining confidence in your structure unless there is something very rare that is in play.

    Cheers and good luck!


  1. […] Récemment Darren Beales a écrit un post très interessant sur l’hypothèse plausible des patients ressentant cette assymétrie pelvienne disponible sur pain-ed.com et bodyinmind.org. […]