Measuring Sacroiliac Joint Movement

In this article I will briefly discuss two areas of sacroiliac joint measurement. Following a more in-depth reading of literature on the pelvic girdle region I have changed my understanding on the assessment of this region. The two areas to be discussed are;

1. Measurement of innominate rotation in standing
2. Gillet’s test (Stalk test)

1. Measurement of innominate rotation in standing

The CHEK inclinometer is an excellent tool for measuring apparent innominate rotation. One arm can be placed on the apex of the posterior superior iliac spine (PSIS) and another on the apex of the anterior superior iliac spine. It is not my intention to discuss the accuracy of identification of bony landmarks in this article. However, on a recent course I attended in which the audience consisted largely of chiropractic and osteopathic lecturers it was evident approximately attendees could accurately identify these landmarks about 60% of the time. Therefore these measurements are open to substantial error. Nonetheless I have found them clinically useful.

I used to see these measurements as indicating the anterior rotation of each innominate. I have seen discrepancies of greater than 5 degrees between sides regularly. In fact, when my own pelvis was first measured the readings were 6 degrees of anterior rotation right and 18 degrees on the left! Obviously as there is very rarely greater 2 degrees of motion (Vleeming et al 2012) in the sacroiliac joint these readings cannot be measuring pure rotation.

In the case of my readings what this must have actually indicated is a shift of weight on to my right leg with a concomitant right rotation of the pelvis in a transverse axis and adduction of the right leg with abduction of the leg. This gives the impression of anteriorly rotated left innominate. It’s possible 2 degrees of the discrepancy came from true anterior rotation, a little more from measurement error but the rest is most likely made of these external pelvic motions.

Interestingly, I have regularly seen greater than 5 degree discrepancies correct in the past following stretching or manual techniques I deemed were targeting the sacroiliac joint. With hindsight these interventions probably had their effect through the soft tissues by normalising external pelvic length tension relationships. As opposed to the sacroiliac joint I thought I was targeting.

2. Gillet’s test

I have assessed Gillet’s test in well over 300 patients in the last few years. In doing so I was sure I was assessing sacroiliac motion. For example, I may feel the right side was not posteriorly rotating as freely on one side. Often this would be coupled with hiking of that hip which I may have attribute to a potential upslip of that innominate. However, I know feel that the apparent lack of posterior rotation of the right innominate may be due to excessive force closure from the anterior thigh musculature relative to posterior hip musculature. Thus to complete hip flexion left hip abduction and right innominate hiking are used.

The reason for this is realistically 2 degrees of sacroiliac motion is going to be very challenging to detect through the thoracolumbar fascia, sacral multifidus and gluteus maximus fibres pervading the region. Indeed Sturesson et al (2000) found very low levels of movement in the test and no difference between asymptomatic and symptomatic sides.

This does not mean I’ve stopped using the test. To the contrary I know find it much more useful as it informs my understanding of the load transfer through the pelvic girdle. I now modify the test by palpating the PSIS’s bilaterally when assessing each leg and assess external pelvic motion as suggested by Vleeming (2012b). I have found this understanding has led to me using my specific innominate rotations less and specific activation and stretching interventions more. To date the effects on the standing hip flexion assessment have been as immediate and appear to have more functional carry over. However, it is very early days.

Conclusion

On reading more of the literature on this topic my first response was to reject the claims. I knew what I was feeling with fingers, the research could have been have precise enough. The late Karel Lewitt insisted he was able to palpate sacroiliac movement and having seen him work I would not reject his claims. However, for mere mortals detecting 2 degrees of motion through a multitude of contractile and non-contractile tissue is very challenging. Fortunately I have this new understanding provides even more powerful insight on external pelvic motion that I once thought assessed internal pelvic motion.