The purpose of this article is to present information on the SIJ, and introduce joint spring tests to qualitatively evaluate motion. The SIJ may cause pain due to disease, inflammation, or movement dysfunction. The important relation ship of the SIJ and pelvis to the rest of the musculoskeletal system should not be ignored in the absence of pain. Movement dysfunction may exist as hypermobility or as hypomobility. If the SIJ is hypomobile or hypermobile it cannot effectively dissipate stress from activities of daily living.
Confusion exists as to how hypermobility and hypomobility are defined.
True hypermobility can be hereditary or traumatic. Apparent hypermobility and apparent hypomobility often co-exist. This is quite common, and treatment directed at restoring normal movement in the direction of hypomobility usually restores normal movement in the direction of the apparent hypermobility as well. SIJ dysfunction during pregnancy is not limited to true hypermobility. The former can be more symptomatic and after reducing the acute strain pattern the background hypermobility can be managed more readily.