Regarding the suggested mobilization to the SI via standing on the sacrum. Mobility restriction of the sacrum can be evaluated and treated in flexion, extension and neutral and treated in same position, based on passive motion testing. Common restrictions are: pure left and right rotation about a pure vertical axix, side bending R/L, combined rotation and side bending about an oblique R/L axis, pure anterior glide, pure posterior glide (this will lock all accessory Wikipedia reference-linkSIJ motions), forward and backward bending, and in cases of significant trauma/significant hypermobility can have obliqu glides or lateral tilt (medial glide applied to S4-5 which is distinctly different from side bending). I have never found pure R/L side glide motion /motion restriction. In the presence of one direction of blocked mobility, the opposite direction is often hypermobile. These are the typical day to day presentations and there are exceptions in which hypermobility or hypomobility aremore global. Treating the hypo is quite rewarding as the hypo also reduces, bringing both directions towards the norm. The sacrum and the ilium/illia and symphysis pubis, sacrococcygeeal and L-S joints and hip are inextricably linked and must be evaluated and treated as a unified whole. Furthermore, I never treat an SI or pelvis without seeking out the compensatory pattern that is often found at the Occipitoatlantal region. The talo-crural and subtalar joints are often also involved and if restrictions are present (such as supinatory fixation) can be addressed with sequential mobilization as the pattern permutates with approriate follow up (to mobilization) exercise.The point I am making is that general mobs to the sacrum without a clear and concise evaluative rationale will provide limited results. The viscoelastic nature of the SI of course must be addressed appropriately.
Jerry Hesch, MHS PT
www.heschmethod.com