Three-Dimensional X-ray Analysis of Normal Movement in the Lumbar Spine.PEARCY, MARK PhD; PORTEK, IAN FRACP; SHEPHERD, JANISSpine: April 1984 Original Article: PDF Only Abstract Biplanar radiography was used to assess the normal three-dimensional movements of the lumbar spine in the erect posture in a group of asymptomatic volunteers. The primary movements investigated were flexion and extension, while the three-dimensional analysis also measured any associated coupled lateral bends and axial rotations. The results showed that each intervertebral joint had a total range of flexion and extension of approximately 14[degrees], the lower levels moving slightly more than the upper levels. All the intervertebral joints had more movement in flexion than extension from the upright position, except for the L5/S1 joint, which showed no consistent pattern, some subjects extending more than flexing. Coupled movements of 4[degrees] or more in flexion and 3[degrees] or more in extension were shown to be abnormal. (C) Lippincott-Raven Publishers.