A technique for measurement and description of three-dimensional six degree-of-freedom motion of a body joint with an application to the human spine.

Abstract A new experimental technique for the measurement of three-dimensional six degrees-of-freedom motion of a body joint and data reduction is presented. It utilizes three spheres that are rigidly attached to the moving body. Six of the nine components of three translation vectors of centers of the spheres are measured by six linear variable differential transformers (LVDT). Data is recorded in real-time by a minicomputer Equations are derived to compute the three Euler rotation angles and the three-dimensional translation vector at a given point of the rigid body. Further, this six-dimensional motion vector is transformed into six parameters that describe the instantaneous helical axis of motion of the joint. Practical considerations in developing a program to compute these helical axis parameters are presented. The technique has been successfully employed to study kinematics of the human spine segments. Examples for the L3-4 lumbar spine segment, subjected to different loads are included. This technique, although especially developed for the in vitro study of the three-dimensional flexibility measurements of the spine segments, may be advantageously utilized in other situations where small three-dimensional motion needs to be studied with high accuracy and in real-time.

[1]  G L Kinzel,et al.  Measurement of the total motion between two body segments. I. Analytical development. , 1972, Journal of biomechanics.

[2]  C. L. Nash,et al.  Spinal analysis using a three-dimensional radiographic technique. , 1976, Journal of biomechanics.

[3]  A. Schultz,et al.  Mechanical Properties of Human Lumbar Spine Motion Segments—Part I: Responses in Flexion, Extension, Lateral Bending, and Torsion , 1979 .

[4]  G L Kinzel,et al.  Measurement of the total motion between two body segments. II. Description of application. , 1972, Journal of biomechanics.

[5]  F G Lippert,et al.  The feasibility of photogrammetry as a clinical research tool. , 1973, Journal of biomechanics.

[6]  Y Youm,et al.  Kinematic investigation of normal MCP joint. , 1978, Journal of biomechanics.

[7]  M M Panjabi,et al.  A note on defining body parts configurations. , 1974, Journal of biomechanics.

[8]  M M Panjabi,et al.  Effects of preload on load displacement curves of the lumbar spine. , 1977, The Orthopedic clinics of North America.

[9]  A. White,et al.  Biomechanical analysis of clinical stability in the cervical spine. , 1975, Clinical orthopaedics and related research.

[10]  Y Youm,et al.  Analytical development in investigation of wrist kinematics. , 1979, Journal of biomechanics.

[11]  M Panjabi,et al.  A mathematical approach for three-dimensional analysis of the mechanics of the spine. , 1971, Journal of biomechanics.

[12]  C H Suh,et al.  The fundamentals of computer aided X-ray analysis of the spine. , 1974, Journal of biomechanics.

[13]  J P Carret,et al.  A technique for joint center analysis using a stored program calculator. , 1976, Journal of biomechanics.