Fig 8.

Example of how the Pelvic Inclination Correction System (PICS) corrects for a −15° pelvic rotation caused by knee support, on the right. a A right-handed local pelvic coordinate system, xy, is located with its origin at the inferior pubic point and its positive x-axis oriented cranio-dorsally along the SCIPP line. A corresponding local coordinate system, x’y’, is defined with the same origin, but with its x-axis rotated −34° from the SCIPP line in the mid-sagittal plane, so that its y’-axis lies along the whole body and scanner axis. b When the pelvis is rotated by a knee support (e to f), the pelvis rotates through −15° carrying the PICS line with it. c, d Note that the dimensions of the triangle PCA do not change because of the pelvic rotation of −15°. P inferior pubic bone point, C cervix, A, intersection of the perpendicular line from the organ to the PICS line. e, f The PICS line rotates when the pelvis rotates