Journal of biomechanics
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Journal of biomechanics · May 2015
Bootstrap prediction bands for cervical spine intervertebral kinematics during in vivo three-dimensional head movements.
There is substantial inter-subject variability in intervertebral range of motion (ROM) in the cervical spine. This makes it difficult to define "normal" ROM, and to assess the effects of age, injury, and surgical procedures on spine kinematics. The objective of this study was to define normal intervertebral kinematics in the cervical spine during dynamic functional loading. ⋯ For a targeted coverage of 90%, the estimated true coverage using bootstrap prediction bands averaged 86±5%, while the estimated true coverage using Gaussian point-by-point intervals averaged 56±10% over all movements and all motion segments. Bootstrap prediction bands are recommended as the standard for evaluating full ROM cervical spine kinematic curves. The data presented here can be used to identify abnormal motion in patients presenting with neck pain, to drive computational models, and to assess the biofidelity of in vitro loading paradigms.
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Journal of biomechanics · May 2015
Three-dimensional intervertebral kinematics in the healthy young adult cervical spine during dynamic functional loading.
The objective of this study was to determine the intervertebral kinematics of the young, healthy cervical spine during dynamic, three-dimensional, functional loading. Intervertebral motion was characterized by the range of motion (ROM) and the helical axis of motion (HAM). Biplane radiographs of the cervical spine were collected at 30 images/s as 29 participants (20-35 yr) performed dynamic flexion\extension, axial rotation, and lateral bending. ⋯ During lateral bending, the angle between the HAM and the transverse plane progressively increased from the C6-C7 motion segment (approximately ±22°) to the C3-C4 motion segment (approximately ±40°). During axial rotation, the angle between the transverse plane and the HAM was approximately ±42° at the C3-C4 through C5-C6 motion segments, and approximately ±32° at the C6-C7 motion segment. This study provides valuable reference data for evaluating the effects of age, degeneration, and surgical procedures on cervical spine kinematics during three-dimensional dynamic functional loading.