title: Cervical spine intervertebral kinematics with respect to the head are different during flexion and extension motions.
abstract: Previous dynamic imaging studies of the cervical spine have focused entirely on intervertebral kinematics while neglecting to investigate the relationship between head motion and intervertebral motion. Specifically, it is unknown if the relationship between head and intervertebral kinematics is affected by movement direction. We tested the hypothesis that there would be no difference in sagittal plane intervertebral angles at identical head orientations during the flexion and extension movements. Nineteen asymptomatic subjects performed continuous head flexion-extension movements while biplane radiographs were collected at 30 images per second. A previously validated model-based volumetric tracking process determined three-dimensional vertebral position with sub-millimeter accuracy throughout the flexion-extension motion. Head movement was recorded at 60 Hz using conventional motion analysis and reflective markers. Intervertebral angles were determined at identical head orientations during the flexion and extension movements. Cervical motion segments were in a more extended orientation during flexion and in a more flexed orientation during extension for any given head orientation. The results suggest that static radiographs cannot accurately represent vertebral orientation during dynamic motion. Further, data should be collected during both flexion and extension movements when investigating intervertebral kinematics with respect to global head orientation. Also, in vitro protocols that use intervertebral total range of motion as validation criteria may be improved by assessing model fidelity using continuous intervertebral kinematics in flexion and in extension. Finally, musculoskeletal models of the head and cervical spine should account for the direction of head motion when determining muscle moment arms because vertebral orientations (and therefore muscle attachment sites) are dependent on the direction of head motion.
authors.affiliation: Orthopaedic Research Laboratories, Department of Orthopaedic Surgery, University of Pittsburgh, 3820 South Water Street, Pittsburgh, PA 15203, USA. anderst@pitt.edu
authors.forename: William J
authors.initials: WJ
authors.lastname: Anderst
authors.forename: William F
authors.initials: WF
authors.lastname: Donaldson
authors.forename: Joon Y
authors.initials: JY
authors.lastname: Lee
authors.forename: James D
authors.initials: JD
authors.lastname: Kang
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D002574:Cervical Vertebrae / Q000502:physiology*; D005260:Female; D019416:Head Movements / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D016059:Range of Motion, Articular / Q000502:physiology*
references.citation: Spine (Phila Pa 1976). 1992 May;17(5):467-74
references.pmid: 1621143
references.citation: Spine (Phila Pa 1976). 2004 Dec 15;29(24):2832-43
references.pmid: 15599287
references.citation: Eur Spine J. 2006 Aug;15(8):1183-8
references.pmid: 16311755
references.citation: J Biomech. 2007;40(5):1038-47
references.pmid: 17141789
references.citation: J Biomech. 2009 Jun 19;42(9):1350-4
references.pmid: 19403137
references.citation: J Bone Joint Surg Am. 2009 Aug;91(8):1882-9
references.pmid: 19651945
references.citation: J Biomech. 2009 Mar 11;42(4):480-90
references.pmid: 19200548
references.citation: N Engl J Med. 2009 Aug 27;361(9):849-57
references.pmid: 19710483
references.citation: Spine (Phila Pa 1976). 2008 Feb 15;33(4 Suppl):S101-22
references.pmid: 18204385
references.citation: Am J Sports Med. 2005 Jan;33(1):102-7
references.pmid: 15611005
references.citation: J Arthroplasty. 2011 Jan;26(1):88-97
references.pmid: 20347253
references.citation: Spine (Phila Pa 1976). 2007 Nov 1;32(23):2578-84
references.pmid: 17978657
references.citation: Spine (Phila Pa 1976). 2010 Apr 20;35(9):939-47
references.pmid: 20375779
references.citation: Clin Biomech (Bristol, Avon). 2002 Jan;17(1):21-31
references.pmid: 11779643
references.citation: J Bone Joint Surg Am. 1963 Sep;45:1171-8
references.pmid: 14077981
references.citation: Spine (Phila Pa 1976). 2009 Mar 15;34(6):E202-7
references.pmid: 19282725
references.citation: Med Eng Phys. 2010 Jun;32(5):482-9
references.pmid: 20392660
references.citation: Spine J. 2010 Jun;10(6):497-504
references.pmid: 20359957
references.citation: Spine (Phila Pa 1976). 1998 Dec 15;23(24):2701-12
references.pmid: 9879096
references.citation: J Orthop Res. 1988;6(5):713-20
references.pmid: 3404328
references.citation: J Biomech. 2002 Apr;35(4):543-8
references.pmid: 11934426
references.citation: J Biomech Eng. 2013 Jun;135(6):61007-8
references.pmid: 23699719
references.citation: J Spinal Disord Tech. 2010 Jun;23(4):278-84
references.pmid: 20068468
references.citation: J Biomech. 2011 Mar 15;44(5):924-9
references.pmid: 21227425
references.citation: Clin Neurosurg. 1978;25:174-83
references.pmid: 709993
references.citation: J Orthop Res. 2004 Jul;22(4):794-800
references.pmid: 15183436
references.citation: Spine (Phila Pa 1976). 2011 Mar 15;36(6):E393-400
references.pmid: 21372650
references.citation: J Biomech. 2005 Feb;38(2):255-62
references.pmid: 15598451
references.citation: J Biomech. 2012 Sep 21;45(14):2362-7
references.pmid: 22840756
references.citation: J Bone Joint Surg Am. 1990 Sep;72(8):1178-84
references.pmid: 2398088
references.citation: Clin Orthop Relat Res. 2007 Jan;454:66-73
references.pmid: 17091011
references.citation: Spine (Phila Pa 1976). 1978 Mar;3(1):12-20
references.pmid: 347598
references.citation: Clin Biomech (Bristol, Avon). 2012 Mar;27(3):226-33
references.pmid: 22019300
references.citation: J Bone Joint Surg Am. 2013 Mar 20;95(6):497-506
references.pmid: 23515984
references.citation: Eur Spine J. 2002 Aug;11(4):358-63
references.pmid: 12193998
references.citation: J Biomech Eng. 2006 Aug;128(4):604-9
references.pmid: 16813452
references.citation: J Spinal Disord Tech. 2010 Feb;23(1):15-21
references.pmid: 20051924
references.citation: Clin Biomech (Bristol, Avon). 2013 Feb;28(2):151-6
references.pmid: 23218255
references.citation: Spine (Phila Pa 1976). 1988 Jul;13(7):748-55
references.pmid: 3194782
references.citation: Med Eng Phys. 2009 Jan;31(1):10-6
references.pmid: 18434230