0
We're unable to sign you in at this time. Please try again in a few minutes.
Retry
We were able to sign you in, but your subscription(s) could not be found. Please try again in a few minutes.
Retry
There may be a problem with your account. Please contact the AMA Service Center to resolve this issue.
Contact the AMA Service Center:
Telephone: 1 (800) 262-2350 or 1 (312) 670-7827  *   Email: subscriptions@jamanetwork.com
Error Message ......
ARTICLE |

Biomechanics of the Spine

James M. Morris, MD
Arch Surg. 1973;107(3):418-423. doi:10.1001/archsurg.1973.01350210054017.
Text Size: A A A
Published online

The basic anatomy of the vertebrae and disc is presented. Instrinsic spinal stability is provided by the intervertebral discs and ligaments, extrinsic stability by the muscles. In the sagittal plane the axis of motion is related to the disc; in the horizontal plane it is determined by facet orientation.

The vertebral end-plates are most susceptible to injury, followed by the vertebral body and the disc. The end-plates tolerate greater dynamic than static forces. Muscle action during lifting decreases the load on the intervertebral discs by transforming the thorax and abdomen into semirigid-walled cylinders. Interdiscal pressure is greatest while sitting, less in standing, and least reclining.

Bracing provides incomplete immobilization, but substitutes for abdominal muscle action. The inflated corset decreases disc pressure by increasing intra-abdominal and intrathoracic pressures. Abdominal strengthening exercises can be of benefit in low back disorders by the same mechanism.

Topics

Sign in

Create a free personal account to sign up for alerts, share articles, and more.

Purchase Options

• Buy this article
• Subscribe to the journal

Figures

Tables

References

Correspondence

CME
Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.
NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).
Submit a Comment

Multimedia

Some tools below are only available to our subscribers or users with an online account.

Sign in

Create a free personal account to sign up for alerts, share articles, and more.

Purchase Options

• Buy this article
• Subscribe to the journal

Related Content

Customize your page view by dragging & repositioning the boxes below.

Jobs
brightcove.createExperiences();