Sacroiliac kinematics for reciprocal straddle positions.

Abstract

A descriptive and correlation approach was used to assess joint motion. Magnitudes and directions of sacroiliac motion were examined from three different upright postural conditions. Evidence and clinical views suggest that sacroiliac motion available in the normal case is extremely small to nonexistent. Systems for standardizing the three postures and the Metrecom skeletal analysis system (Metrecom, Faro Technologies, Inc., Lake Mary, FL) for acquiring coordinate data for selected skeletal landmarks. The complete sacroiliac oblique-sagittal motion that occurred between the right forward and left forward stride positions was 9 degrees (SD 6.5). The composite oblique-transverse motion was 5 degrees (SD 3.9). The motions in each plane were significantly different from zero. A joint mobility relationship existed between the hip and sacroiliac joints. The results demonstrate that substantial angular motion is possible at the sacroiliac joints.