Keessen W, During J, Beeker T W, Goudfrooij H, Crowe A
Spine (Phila Pa 1976). 1984 Jan-Feb;9(1):83-90. doi: 10.1097/00007632-198401000-00019.
The pathomechanism of low-back pain generation is not understood very well. Functional disturbances of motion at the individual segmental level appear to play a role in many cases. In this study a technique of numeric analysis of radiographic observations of the lumbar spine is developed by which the authors are able to assess the displacement of the two components of the L5-S1 motion segment in the sagittal plane when the subject assumes three specified standard postural positions.