MECHANICAL AND KINEMATIC ANALYSIS OF THE LUMBAR SPINE IN NORMAL LIVING HUMAN SUBJECTS INVIVO

This paper describes the principles of an apparatus which incorporates orthogonal radiography with a method of placing and holding human subjects, and moving them through easily indexed ranges of motion. This device is used to analyze the three dimensional motion characteristics of the human spine in vivo. The behavior of spinal segments in cadaveric subjects analyzed by this method and the living subjects reported herein shows similar motion characteristics. The most important attribute of this spinal behavior is the complex coupling which occurs. Translations and rotations about three mutually perpendicular axes are coupled in reasonably predictable ways dependent upon the motion segment and most likely upon the orientations of facets, as well as possibly the inherent state of the intervertebral disc. © 1979.