Tags

Type your tag names separated by a space and hit enter

The neutral posture of the cervical spine is not unique in human subjects.
J Biomech. 2018 10 26; 80:53-62.JB

Abstract

Cervical spine injuries often happen in dynamic environments (e.g., sports and motor vehicle crashes) where individuals may be moving their head and neck immediately prior to impact. This motion may reposition the cervical vertebrae in a way that is dissimilar to the upright resting posture that is often used as the initial position in cadaveric studies of catastrophic neck injury. Therefore our aim was to compare the "neutral" cervical alignment measured using fluoroscopy of 11 human subjects while resting in a neutral posture and as their neck passed through neutral during the four combinations of active flexion and extension movements in both an upright and inverted posture. Muscle activation patterns were also measured unilaterally using surface and indwelling electromyography in 8 muscles and then compared between the different conditions. Overall, the head posture, cervical spine alignment and muscle activation levels were significantly different while moving compared to resting upright. Compared to the resting upright condition, average head postures were 6-13° more extended, average vertebral angles varied from 11° more extended to 10° more flexed, and average muscle activation levels varied from unchanged to 10% MVC more active, although the exact differences varied with both direction of motion and orientation. These findings are important for ex vivo testing where the head and neck are statically positioned prior to impact - often in an upright neutral posture with negligible muscle forces - and suggest that current cadaveric head-first impact tests may not reflect many dynamic injury environments.

Links

Publisher Full Text (DOI)

Authors+Show Affiliations

Newell RS
University of British Columbia, School of Biomedical Engineering, Vancouver, British Columbia, Canada; University of British Columbia, Department of Mechanical Engineering, Vancouver, British Columbia, Canada; University of British Columbia, International Collaboration on Repair Discoveries, Vancouver, British Columbia, Canada; University of British Columbia, Orthopaedic and Injury Biomechanics Group, Departments of Mechanical Engineering and Orthopaedics, Vancouver, British Columbia, Canada.
Blouin JS
University of British Columbia, School of Kinesiology, Vancouver, British Columbia, Canada; University of British Columbia, Brain Research Center, Vancouver, British Columbia, Canada; University of British Columbia, Institute for Computing, Information and Cognitive Systems, Vancouver, British Columbia, Canada.
Street J
University of British Columbia, Combined Neurosurgical and Orthopaedic Spine Program, Vancouver, British Columbia, Canada; University of British Columbia, International Collaboration on Repair Discoveries, Vancouver, British Columbia, Canada; Department of Orthopaedics, University of British Columbia, Vancouver, British Columbia, Canada.
Cripton PA
University of British Columbia, School of Biomedical Engineering, Vancouver, British Columbia, Canada; University of British Columbia, Department of Mechanical Engineering, Vancouver, British Columbia, Canada; University of British Columbia, International Collaboration on Repair Discoveries, Vancouver, British Columbia, Canada; University of British Columbia, Orthopaedic and Injury Biomechanics Group, Departments of Mechanical Engineering and Orthopaedics, Vancouver, British Columbia, Canada.
Siegmund GP
University of British Columbia, School of Kinesiology, Vancouver, British Columbia, Canada; MEA Forensic Engineers & Scientists, Richmond, British Columbia, Canada. Electronic address: gunter.siegmund@meaforensic.com.

MeSH

Accidents, TrafficAdultCervical VertebraeElectromyographyFemaleFluoroscopyHeadHumansMaleMovementNeckNeck InjuriesNeck MusclesPostureRange of Motion, ArticularYoung Adult

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

30170839

Citation

Newell, Robyn S., et al. "The Neutral Posture of the Cervical Spine Is Not Unique in Human Subjects." Journal of Biomechanics, vol. 80, 2018, pp. 53-62.
Newell RS, Blouin JS, Street J, et al. The neutral posture of the cervical spine is not unique in human subjects. J Biomech. 2018;80:53-62.
Newell, R. S., Blouin, J. S., Street, J., Cripton, P. A., & Siegmund, G. P. (2018). The neutral posture of the cervical spine is not unique in human subjects. Journal of Biomechanics, 80, 53-62. https://doi.org/10.1016/j.jbiomech.2018.08.012
Newell RS, et al. The Neutral Posture of the Cervical Spine Is Not Unique in Human Subjects. J Biomech. 2018 10 26;80:53-62. PubMed PMID: 30170839.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The neutral posture of the cervical spine is not unique in human subjects. AU - Newell,Robyn S, AU - Blouin,Jean-Sébastien, AU - Street,John, AU - Cripton,Peter A, AU - Siegmund,Gunter P, Y1 - 2018/08/22/ PY - 2018/02/27/received PY - 2018/08/14/revised PY - 2018/08/15/accepted PY - 2018/9/2/pubmed PY - 2019/6/18/medline PY - 2018/9/2/entrez KW - Motion KW - Muscles KW - Neck injury KW - Posture KW - Upside down SP - 53 EP - 62 JF - Journal of biomechanics JO - J Biomech VL - 80 N2 - Cervical spine injuries often happen in dynamic environments (e.g., sports and motor vehicle crashes) where individuals may be moving their head and neck immediately prior to impact. This motion may reposition the cervical vertebrae in a way that is dissimilar to the upright resting posture that is often used as the initial position in cadaveric studies of catastrophic neck injury. Therefore our aim was to compare the "neutral" cervical alignment measured using fluoroscopy of 11 human subjects while resting in a neutral posture and as their neck passed through neutral during the four combinations of active flexion and extension movements in both an upright and inverted posture. Muscle activation patterns were also measured unilaterally using surface and indwelling electromyography in 8 muscles and then compared between the different conditions. Overall, the head posture, cervical spine alignment and muscle activation levels were significantly different while moving compared to resting upright. Compared to the resting upright condition, average head postures were 6-13° more extended, average vertebral angles varied from 11° more extended to 10° more flexed, and average muscle activation levels varied from unchanged to 10% MVC more active, although the exact differences varied with both direction of motion and orientation. These findings are important for ex vivo testing where the head and neck are statically positioned prior to impact - often in an upright neutral posture with negligible muscle forces - and suggest that current cadaveric head-first impact tests may not reflect many dynamic injury environments. SN - 1873-2380 UR - https://www.unboundmedicine.com/medline/citation/30170839/The_neutral_posture_of_the_cervical_spine_is_not_unique_in_human_subjects_ DB - PRIME DP - Unbound Medicine ER -