Comparative strengths and structural properties of the upper and lower cervical spine in flexion and extension

Nightingale, Roger W.; Winkelstein, Beth A.; Knaub, Kurt E.; Richardson, William J.; Luck, Jason F.; Myers, Barry S.

doi:10.1016/s0021-9290(02)00037-4

Cited by 121 publications

(115 citation statements)

References 28 publications

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“…For a specified moment, the shorter moment arm in flexion (d, as seen in Figure 4-5), requires a greater reaction force generated by the ligaments in tension from the dens. The greater force results in increased risk of fracture in flexion compared to extension, and are consistent with lower moment tolerances in flexion compared to extension found in the study (Nightingale et al, 2002). These findings stress the importance of accurate craniovertebral ligament properties for mathematical modeling.…”

Section: Craniovertebral Segment Studiessupporting

confidence: 86%

“…This is of interest because numerous studies have reported these segments as having the largest range of motion in flexion and extension (Van Mameren et al, 1990;Lind et al, 1989;Ito et al, 2004) and axial rotation (Penning et al, 1987). One study found range of motion in flexion/extension to be significantly greater in the C5-C6 (22.8 ± 2.3°) compared to the C7-T1 (13.8 ± 2.8; Nightingale et al, 2002). These similarities between the results of the current study and previous segment tests suggest ligament properties may differ between spinal levels, thus may play a role in the larger range of motion.…”

Section: Spinal Level and Gender Effectssupporting

confidence: 73%

“…Range of motion in flexion and extension was found to be significantly greater in the C5-C6 (22.8 ± 2.3°) compared to the C7-T1 (13.8 ± 2.8°), and C7-T1 was shown to be significantly stronger in flexion than C3-C4, in cervical spine segment tests (Nightingale et al, 2002). Another study found different ranges of motion in whole cervical spine specimen impact testing, where the middle regions (C4-C5, C5-C6) had larger ranges of motion, although not significantly different ).…”

Section: Level Effectsmentioning

confidence: 81%

“…Numerical models have shown that under loading cases, the distractions and forces seen at each spinal level vary (Stemper et al, 2006), and this suggests the importance that ligaments at each spinal level are modeled accurately. Several segment and whole cervical spine studies have reported gender (Pintar et al, 1995;Ferrario et al, 2002;Stemper et al, 2003;Pintar et al, 1998;Nightingale et al, 2007) and spinal level differences (Shea et al, 1991;Nightingale et al, 2002), or recommended further investigation in those areas (Pintar, 1986;Van Ee et al, 2000).…”

Section: Motivation For Researchmentioning

confidence: 99%

“…The mechanical properties of the ligaments that connect the dens to the skull are important, as these ligaments are thought to play a significant role in tensile loading of the dens, resulting in fracture (Nightingale et al, 2002;Nightingale et al, 2007). Under flexion, the compression force of the skull and the anterior arch of the C1, and the tensile force of the ligaments on the dens create a couple moment (Figure 4-5).…”

Section: Craniovertebral Segment Studiesmentioning

confidence: 99%

See 4 more Smart Citations

Strain rate dependent properties of younger human cervical spine ligaments

Mattucci

Moulton

Chandrashekar

et al. 2012

Journal of the Mechanical Behavior of Biomedical Materials

124

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Section: Craniovertebral Segment Studiessupporting

confidence: 86%

Section: Spinal Level and Gender Effectssupporting

confidence: 73%

Section: Level Effectsmentioning

confidence: 81%

Section: Motivation For Researchmentioning

confidence: 99%

Section: Craniovertebral Segment Studiesmentioning

confidence: 99%

See 3 more Smart Citations

Strain rate dependent properties of younger human cervical spine ligaments

Mattucci

Moulton

Chandrashekar

et al. 2012

Journal of the Mechanical Behavior of Biomedical Materials

124

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An investigation of dimensional scaling using cervical spine motion segment finite element models

Singh

Cronin

2017

Numer Methods Biomed Eng

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The paucity of experimental data for validating computational models of different statures underscores the need for appropriate scaling methods so that models can be verified and validated using experimental data. Scaling was investigated using 50th percentile male (M50) and 5th percentile female (F05) cervical spine motion segment (C4-C5) finite element models subject to tension, flexion, and extension loading. Two approaches were undertaken: geometric scaling of the models to investigate size effects (volumetric scaling) and scaling of the force-displacement or moment-angle model results (data scaling). Three sets of scale factors were considered: global (body mass), regional (neck dimensions), and local (segment tissue dimensions). Volumetric scaling of the segment models from M50 to F05, and vice versa, produced correlations that were good or excellent in both tension and flexion (0.825-0.991); however, less agreement was found in extension (0.550-0.569). The reduced correlation in extension was attributed to variations in shape between the models leading to nonlinear effects such as different time to contact for the facet joints and posterior processes. Data scaling of the responses between the M50 and F05 models produced similar trends to volumetric scaling, with marginally greater correlations. Overall, the local tissue level and neck region level scale factors produced better correlations than the traditional global scaling. The scaling methods work well for a given subject, but are limited in applicability between subjects with different morphology, where nonlinear effects may dominate the response.

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On the importance of retaining stresses and strains in repositioning computational biomechanical models of the cervical spine

Boakye‐Yiadom

Cronin

2017

Numer Methods Biomed Eng

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Human body models are created in a specific posture and often repositioned and analyzed without retaining stresses that result from repositioning. For example, repositioning a human neck model within the physiological range of motion to a head-turned posture prior to an impact results in initial stresses within the tissues distracted from their neutral position. The aim of this study was to investigate the effect of repositioning on the subsequent kinetics, kinematics, and failure modes, of a lower cervical spine motion segment, to support future research at the full neck level. Repositioning was investigated for 3 modes (tension, flexion, and extension) and 3 load cases. The model was repositioned and loaded to failure in one continuous load history (case 1), or repositioned then restarted with retained stresses and loaded to failure (case 2). In case 3, the model was repositioned and then restarted in a stress-free state, representing current repositioning methods. Not retaining the repositioning stresses and strains resulted in different kinetics, kinematics, or failure modes, depending on the mode of loading. For the motion segment model, the differences were associated with the intervertebral disc fiber reorientation and load distribution, because the disc underwent the largest deformation during repositioning. This study demonstrated that repositioning led to altered response and tissue failure, which is critical for computational models intended to predict injury at the tissue level. It is recommended that stresses and strains be included and retained for subsequent analysis when repositioning a human computational neck model. | INTRODUCTION AND BACKGROUNDRecently, extensive efforts are being made with automotive crash simulations and computational models to address occupant safety challenges, such as out-of-position scenarios, using advanced finite element human body models (HBM). [1][2][3][4] These models incorporate representations of soft and hard tissues including bones surrounded by muscles, tendons, and ligaments such as the total human model for safety, human models for safety (HUMOS2), and the HBMs developed by the global human Received: 20 September 2016 Revised: 29 May body models consortium (GHBMC). [5][6][7] Although these HBMs have demonstrated new potential to evaluate injuries at the tissue level, they are often created in a specific position such as a seated driving posture and therefore must be morphed or repositioned to other important postures such as standing in the case of a pedestrian, or may be repositioned to investigate postural effects for specific body regions such as the neck or thorax. 3,4 In addition, integrating an occupant HBM with a vehicle model may require considering different positions of the HBMs compared to the standardized positions of the models. [8][9][10] This implies that repositioning of body regions or the entire HBM may be required for analysis of different impact scenarios; however, in current methods the focus has been on retaining mesh quality,...

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Comparative strengths and structural properties of the upper and lower cervical spine in flexion and extension

Cited by 121 publications

References 28 publications

Strain rate dependent properties of younger human cervical spine ligaments

Strain rate dependent properties of younger human cervical spine ligaments

An investigation of dimensional scaling using cervical spine motion segment finite element models

On the importance of retaining stresses and strains in repositioning computational biomechanical models of the cervical spine

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