Margulies S S, Yuan Q, Guccione S J, Weiss M S
Department of Bioengineering, University of Pennsylvania, Philadelphia 19104-6392, USA.
Aviat Space Environ Med. 1998 Sep;69(9):896-903.
The dynamic head-neck responses of human subjects and cadavers undergoing involuntary impact loading conditions have been studied extensively in order to define the kinematics of the neck undergoing rapid movements, but little detailed information is available regarding slower, voluntary motions. In this study, the dynamic kinematics of head/neck complex during subject-controlled, or voluntary head motion have been investigated to compare with the kinematics to involuntary response. Five male human subjects experienced two-types of posterior/anterior neck flexion: flexion initiated under their own volition, and flexion in response to -15Gx acceleration of the torso. Tri-axial photo target mounts were placed on a custom-fit plate at the mouth, on the first thoracic vertebra, and on the sled. High speed movie cameras captured the photo target motion. Linear and angular displacement and velocity of the head and T1 and sled were computed using customized data-processing software. The neck kinematics were represented by a 2-pin linkage which connected the anatomical origins of the head and T1.
The results show that maximum neck flexion relative to the torso was not significantly different between the voluntary and involuntary head motions, but that the head motion was significantly greater during the involuntary sled maneuvers. Maximum flexion velocities of 450 and 1236 degrees x s(-1) were sustained during the voluntary and involuntary maneuvers, respectively.
These findings are important in understanding the kinematics of the human head/neck complex undergoing rapid and slow movements, and will be valuable in future studies determining a realistic physiological performance corridor for the human neck.
为了确定颈部在快速运动时的运动学特征，人们对处于非自愿冲击负荷条件下的人体受试者和尸体的头部 - 颈部动态反应进行了广泛研究，但关于较慢的自愿运动的详细信息却很少。在本研究中，对受试者控制的或自愿的头部运动过程中头/颈复合体的动态运动学进行了研究，以与非自愿反应的运动学进行比较。五名男性受试者经历了两种类型的后/前颈部屈曲：一种是在他们自己的意志下开始的屈曲，另一种是对躯干 -15Gx 加速度的反应性屈曲。三轴光靶支架被放置在定制的贴合板上，分别位于口腔处、第一胸椎处和雪橇上。高速电影摄像机捕捉光靶的运动。使用定制的数据处理软件计算头部、T1 和雪橇的线性和角位移及速度。颈部运动学由连接头部和 T1 解剖学原点的双销连杆表示。
结果表明，自愿和非自愿头部运动之间相对于躯干的最大颈部屈曲没有显著差异，但在非自愿雪橇操作期间头部运动明显更大。在自愿和非自愿操作期间，分别维持了 450 和 1236 度×秒⁻¹ 的最大屈曲速度。
这些发现对于理解人类头/颈复合体在快速和缓慢运动时的运动学特征很重要，并且在未来确定人类颈部实际生理性能范围的研究中将具有重要价值。
