The mechanisms by which the human spinal column in neutral postures can resist relatively large axial compression forces with no abnormal motions or instabilities remain yet unknown. A nonlinear finite element study of the ligamentous thoracolumbar spine was performed to investigate the stabilizing role of two plausible mechanisms of combined moments and pelvic rotation on the human spine in axial compression. The passive system, by itself was able to carry only a negligible fraction of physiological compression loads without exhibiting large motions. The unconstrained spine was most flexible in the sagittal plane (least stiff plane). The existence of combined moments and pelvic rotation significantly increased the load-bearing capacity of the spine so that the free standing passive thoracolumbar spine resisted the axial compression forces of more than 1000 N with minimal displacements. The former mechanism is much more effective in stabilizing the spine in compression than is the latter one. It is postulated that the pelvic rotation and the off-centered anterior placement of the gravity force are exploited to partially stabilize the passive spine in compression and relieve the musculature. Previous and on-going studies support the validity of the proposed mechanisms.

Issue Section:
Technical Papers
Topics:
Compression, Human spine, Rotation, Finite element analysis, Gravity (Force), Load bearing capacity, Muscle, Physiology, Stress
1.
Andriacchi
T.
,
Schultz
A.
,
Belytschko
T.
, and
Galante
J.
,
1974
, “
A Model For Studies of Mechanical Interactions Between The Human Spine and Rib Cage
,”
J. Biomech.
, Vol.
7
, pp.
497
–
507
.
2.
Asmussen
E.
,
1960
, “
The Weight Carrying Function of the Human Spine
,”
Acta Orthop Scand
, Vol.
29
, pp.
276
–
290
.
3.
Asmussen
E.
, and
Klausen
K.
,
1962
, “
Form and Function of the Erect Human Spine
,”
Clin Orthop
, Vol.
25
, pp.
55
–
63
.
4.
Bergmark
A.
,
1989
, “
Stability of the Lumbar Spine: A Study in Mechanical Engineering
,”
Acta Orthop Scand
, Vol.
60
(
Suppl 230)
, pp.
1
–
54
.
5.
Bernhardt
M.
, and
Bridwell
K. H.
,
1989
, “
Segmental Analysis of the Sagittal Plane Alignment of the Normal Thoracic and Lumbar Spines and Thoracolumbar Junction
,”
Spine
, Vol.
14
, pp.
717
–
721
.
6.
Byl
N. N.
, and
Sinnot
P. L.
,
1991
, “
Variations in Balance and Body Sway in Middle-aged Adults: Subjects With Healthy Backs Compared With Subjects With Low-Back Dysfunction
,”
Spine
, Vol.
3
, pp.
325
–
330
.
7.
Crisco
J. J.
, and
Panjabi
M.
,
1991
, “
The Intersegmental and Multisegmental Muscles of the Lumbar Spine: A Biomechanical Model Comparing Lateral Stabilizing Potential
,”
Spine
, Vol.
16
, pp.
793
–
808
.
8.
Fernand, R., and Fox, D. E., 1985, “Evaluation of Lumbar Lordosis: A Prospective and Retrospective Study,” Vol. 10, pp. 799–803.
9.
Gilad
I.
, and
Nissan
M.
,
1986
, “
A Study of Vertebra and Disc Geometric Relations of the Human Cervical and Lumbar Spine
,”
Spine
, Vol.
11
, pp.
154
–
157
.
10.
Gracovetsky, S., 1988, The Spinal Engine, Springer-Verlag, New York.
11.
Guran, A., and Shirazi-Adl, A., 1990, “Some Remarks Concerning the Post-Buckling Behaviour of a Compressible Column,” Impact and Buckling of Structures, ASME AMD-Vol. 114, Hui D and Elishkoff I, eds., pp. 93–99.
12.
Guran
A.
, and
Shirazi-Adl
A.
,
1993
, “
Finite Element Analysis of An Elastically Tied Arch Under a Point Load Using Rigid-convected Coordinates
,”
Math. Modelling Sci. Comput.
, Vol.
2
, pp.
1108
–
1113
.
13.
Jakobs
T.
,
Ashton-Miller
J. A.
, and
Schultz
A. B.
,
1985
, “
Trunk Position Sense in the Frontal Plane
,”
Exp. Neurol.
, Vol.
90
, pp.
129
–
138
.
14.
Kalimo
H.
,
Rantanen
J.
,
Viljanen
T.
, and
Einola
S.
,
1989
, “
Lumbar Muscles: Structure and Function
,”
Annals Med.
, Vol.
21
, pp.
353
–
359
.
15.
King Liu, Y. K., and Wickstrom, J. K., 1973, “Estimation of the Inertia Property Distribution of the Human Torso from Segmented Cadaveric Data,” Perspectives in Biomedical Engineering, R. M. Kennedi, ed., McMillan, New York, pp. 203–213.
16.
Kroemer, K., Kroemer, H., and Kroemer-Elbert, K., 1994, Ergonomics, Prentice Hall International Series in Industrial & Systems Engineering, W. J. Fabrycky and J. H. Mize, eds., pp. 291–299.
17.
Lucas, D. B., and Bresler, B., 1960, “Stability of the Ligamentous Spine,” Technical Report Ser. 11, No. 40, Biomechanics Laboratory, University of California, San Francisco, pp. 1–41.
18.
McGlashen
K.
,
Ashton-Miller
J. A.
,
Green
M.
, and
Schultz
A. B.
,
1991
, “
Trunk Positioning Accuracy in the Frontal and Sagittal Planes
,”
J. Orthop. Res.
, Vol.
9
, pp.
576
–
583
.
19.
Nashner
L. M.
, and
McCollum
G.
,
1985
, “
Organization of Postural Human Movement: A Formal Basis and Experiments Synthesis
,”
Behav. Brain Sci.
, Vol.
8
, pp.
135
–
172
.
20.
Orne
D.
, and
King Liu
Y.
,
1971
, “
Mathematical Model of the Spinal Response to Impact
,”
J. Biomech.
, Vol.
4
, pp.
49
–
71
.
21.
Parnianpour
M.
,
Aaron
A.
, and
Li
S.
,
1992
, “
An EMG Study of Muscular Coactivation Theory: The Effect of Pure Compression Load on Spine Stability
,”
38th Orthop. Res. Soc.
, Vol.
17
, Section
1
, p.
142
142
.
22.
Parnianpour, M., Shirazi-Adl, A., Hemami, H., and Quesada, P., 1994, “The Effect of Compressive Load on the Local and Global Postural Stability,” North American Spine Society, #29, Maui, Hawaii.
23.
Scholten
P. J. M.
,
Veldhuizen
A. G.
, and
Grootenboer
H. J.
,
1988
, “
Stability of the Human Spine: A Biomechanical Study
,”
Clinical Biomech.
, Vol.
3
, pp.
27
–
33
.
24.
Schultz
A. B.
,
Belytschko
T. B.
,
Andriacchi
T. D.
, and
Galante
J. O.
,
1973
, “
Analog Studies of Forces in the Human Spine: Mechanical Properties and Motion Segment Behaviour
,”
J. Biomech.
, Vol.
6
, pp.
373
–
383
.
25.
Shirazi-Adl
A.
,
1994
, “
Analysis of Role of Bone Compliance on Mechanics of a Lumbar Motion Segment
,”
J. Biomechanical Eng.
, Vol.
116
, pp.
408
–
412
.
26.
Shirazi-Adl
A.
, and
Parnianpour
M.
,
1993
, “
Nonlinear Response Analysis of the Human Ligamentous Lumbar Spine in Compression: On Mechanisms Affecting the Postural Stability
,”
Spine
, Vol.
18
, pp.
147
–
158
.
27.
Shirazi-Adl, A., Parnianpour, M., Hemami, M., and Quesada, P., 1993, “Determination of Mechanisms to Integrate Local Spinal and Global Postural Stability,” Abstracts, International Society for the Study of the Lumbar Spine, Marseilles, No. 11.
28.
Takashima
S. T.
,
Singh
S. P.
,
Haderspeck
K. A.
, and
Schultz
A. B.
,
1979
, “
A Model for Semi-Quantitative Studies of Muscle Actions
,”
J. Biomech.
, Vol.
12
, pp.
929
–
939
.
29.
Voutsinas
S. A.
, and
Dean MacEwen
G.
,
1986
, “
Sagittal Profiles of the Spine
,”
Clinical Orthop. and Rel. Res.
, Vol.
210
, pp.
235
–
242
.
This content is only available via PDF.
Copyright © 1996
 by The American Society of Mechanical Engineers
You do not currently have access to this content.