Mechanical Properties of Human Lumbar Spine Motion Segments—Part I: Responses in Flexion, Extension, Lateral Bending, and Torsion

In this first part of a three-part report, the mechanical behavior of 42 fresh human cadaver lumbar motion segments in flexion, extension, lateral bending, and torsion is examined. Motions and intradiskal pressure changes that occurred in response to these loads, with posterior elements both intact and excised, are reported.