Pearsall D J, Reid J G, Livingston L A
Department of Physical Education, McGill University, Montréal, Quebec, Canada.
Ann Biomed Eng. 1996 Mar-Apr;24(2):198-210. doi: 10.1007/BF02667349.
This study used computed tomography (CT) imaging to determine in vivo mass, center of mass (CM), and moments of inertia (Icm) about the CM of discrete segments of the human torso. Four subjects, two males and two females, underwent serial transverse CT scans that were collected at 1-cm intervals for the full length of the trunk. The pixel intensity values of transverse images were correlated to tissue densities, thereby allowing trunk section mass properties to be calculated. The percentage of body mass observed by vertebral levels ranged from 1.1% at T1 to 2.6% at L5. The masses of the upper, middle, and lower trunk segments as percentages of body mass were estimated to be 18.5, 12.2, and 10.7%, respectively. The whole trunk mass was estimated to comprise 41.6% of the total body mass. Transverse vertebral CM values were found to lie anterior to their respective vertebral centroids by up to 5.0 cm in the lower thoracic region. For the upper, middle, and lower trunk segments, the average CM positions were found to be 25.9, 62.5, and 86.9% of the distance from the superior to inferior ends of the trunk. The upper and middle trunk CMs corresponded to approximately 4.0 cm anterior to T7/T8 vertebral centroid levels and 1.0 cm anterior to L3/L4 vertebral centroid levels, respectively. For the whole trunk, the CM was 52.7% of the distance from the xiphoid process and approximately 2.0 cm anterior to L1/L2 vertebral centroid levels. Variations in CM and Icm values were observed between subject, but these were within the range of previous reports of body segment parameters. Differences from previous studies were attributable to variations in boundary definitions, measurement techniques, population groups, and body states (live versus cadaver) examined. The disparity between previous findings and findings of this study emphasizes the need to better define the segmental properties of the trunk so that improved biomechanical representation of the body can be achieved.
本研究使用计算机断层扫描（CT）成像来确定人体躯干离散节段的体内质量、质心（CM）以及关于质心的转动惯量（Icm）。四名受试者，两名男性和两名女性，接受了连续的横向CT扫描，扫描在躯干全长范围内以1厘米的间隔进行采集。横向图像的像素强度值与组织密度相关，从而能够计算躯干各节段的质量特性。按椎体水平观察到的体重百分比范围从T1处的1.1%到L5处的2.6%。上、中、下躯干节段的质量占体重的百分比估计分别为18.5%、12.2%和10.7%。整个躯干质量估计占全身质量的41.6%。发现横向椎体质心值在胸段下部比其各自的椎体中心向前最多5.0厘米。对于上、中、下躯干节段，平均质心位置分别为躯干上下两端距离的25.9%、62.5%和86.9%。上躯干和中躯干的质心分别对应于T7/T8椎体中心水平前方约4.0厘米和L3/L4椎体中心水平前方1.0厘米。对于整个躯干，质心位于剑突距离的52.7%处，并且在L1/L2椎体中心水平前方约2.0厘米。在受试者之间观察到质心和转动惯量值的变化，但这些变化在先前身体节段参数报告的范围内。与先前研究的差异归因于边界定义、测量技术、人群组以及所检查的身体状态（活体与尸体）的变化。先前研究结果与本研究结果之间的差异强调了更好地定义躯干节段特性的必要性，以便能够实现对身体更好的生物力学表征。
