An investigation of three-dimensional lumbar position and mobility has been made by combining roentgen stereophotogrammetry with reconstructed solid images of serialized CAT scans of lumbar vertebra. The three-dimensional positions of L3, L4, and L5 in a 56-year old male, unembalmed cadaver were measuredin situwith roengten stereophotogrammetry in four positions of lumbar flexion. The excised bones were cleaned and approximately 30 serialized slices in a CAT scan were obtained. These images were reconstructed using MOVIE.BYU and computer programs developed according to a protocol described in the paper. Six of nine targets in both measurement systems were located with an average difference of distance ranging from 0.4 to 1.0 mm. These computer-generated images have been used to describe local, intervertebral angular movements of .035 to .128 radians and linear movements of .00 to .12 cm as calculated by a “screw axis‘’ analysis. This investigation provides a technology that can potentially be used by both clinicians and engineers in their investgations of local spinal movements in the human body.