Morgan M I, Corrales M A, Kaur H, Cripton P A, Cronin D S
Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, ON, Canada.
Faculties of Applied Science and Faculty of Medicine, School of Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada.
Ann Biomed Eng. 2025 May 15. doi: 10.1007/s10439-025-03745-8.
Head-first impacts (HFI) are associated with a high risk of cervical spine trauma. Experimentally, HFI use an inverted full body (FB), or a head and neck with torso surrogate mass (TSM) attached to the first thoracic vertebra. FB testing is complex and few studies have been completed, while more testing has been done in the TSM configuration, no comparison of the two setups exists.
In this study, the effect of TSM and FB on the head and neck response was investigated computationally using three initial neck postures (flexed, neutral, and extended). The TSM was applied to an extracted head and neck from a contemporary full body model, while the FB was used for comparison. The models were inverted and dropped on a rigid plate at three velocities (2.0, 3.1, and 3.6 m/s). Head impact force, head and neck kinetics, vertebral kinematics, and internal energy were measured and compared between the models.
TSM models demonstrated higher neck forces, and internal energy, compared to FB models. Despite similar head contact forces, the compliant thorax of the FB model reduced the neck forces and energy. The neutral and extended posture predicted higher neck forces due to facet joints engaging, while anterior head translation in the flexed posture reduced neck forces.
This study identified that the neck response using a TSM boundary condition differs from a FB condition, leading to higher neck loads, and that lordotic neck postures lead to higher neck forces compared to a kyphotic initial posture.
头部先着地撞击（HFI）与颈椎创伤的高风险相关。在实验中，HFI使用倒置的全身（FB）模型，或在第一胸椎上附着有躯干替代质量（TSM）的头颈部模型。FB测试很复杂，完成的研究很少，而在TSM配置下进行了更多测试，但不存在对这两种设置的比较。
在本研究中，使用三种初始颈部姿势（屈曲、中立和伸展）通过计算研究了TSM和FB对头部和颈部反应的影响。将TSM应用于从当代全身模型中提取的头颈部，同时使用FB模型进行比较。将模型倒置并以三种速度（2.0、3.1和3.6米/秒）落在刚性板上。测量并比较了模型之间的头部撞击力、头部和颈部动力学、椎体运动学以及内能。
与FB模型相比，TSM模型显示出更高的颈部力和内能。尽管头部接触力相似，但FB模型顺应性的胸部降低了颈部力和能量。由于小关节参与，中立和伸展姿势预测颈部力更高，而屈曲姿势下头部向前平移降低了颈部力。
本研究确定，使用TSM边界条件时的颈部反应与FB条件不同，导致颈部负荷更高，并且与后凸初始姿势相比，前凸颈部姿势会导致更高的颈部力。
