Biomechanical Response of Head/Neck/Torso and Cervical Vertebral Motion to Lateral Impact Loading on the Shoulders of Volunteers

摘要

To understand the response of the head, neck and torso during a lateral collision, and to investigate the relation between cervical vertebral motion and the occurrence of neck injuries, lateral impact experiments were conducted on the shoulder areas of human volunteers. Test subjects consisted of 8 volunteers (5 males and 3 females). For the analysis of cervical vertebral motions of each subject, a cineradiography system was used. A VICON motion photographic device was also used for the three-dimensional analysis of head/neck/torso motions. In the experiment, 3 levels of impact force (400N，500N, and 600N) were applied considering both the presence and absence of muscle tension. Cervical vertebral rotations all started at 35 ms, but the time required to reach the peak rotation increased toward the upper vertebrae, with C7 and T1 peaking at 120 ms and the final peak in the head at 120 ms. At around 35-80 ms, the rotation angle of C5 surpassed those of the head and C4 showing that the cervical spine was bending into an S-curve. This phenomenon shows the same type of cervical vertebral motions causing whiplash during a rear-end collision. Also, extreme compression was at work in the vertebral disc and/or the facet joint in C6/C7 and C7/T1, suggesting a high probability of injury occurring in the neck.