Form and orientation of the sacroiliac joint

Despite the generally accepted importance of form & force closure mechanisms in sacroiliac joint (SIJ) biomechanics, very little is known about SIJ form and orientation, and the relationship between both. This study describes the sagittal orientation of the SIJ relative to gravity, and defines its correlation to intrinsic SIJ form variation using statistical shape modelling. Results show a distinct correlation between joint form and orientation. These findings can help improve insights into both healthy and pathological force transfer in the SIJ.