Harrington M A, Keller T S, Seiler J G, Weikert D R, Moeljanto E, Schwartz H S
School of Medicine, Vanderbilt University, Nashville, TN 37232-0685.
J Biomech. 1993 Apr-May;26(4-5):417-26. doi: 10.1016/0021-9290(93)90005-y.
An image processing system was used to examine histomorphometric properties of 15 adult male and female human clavicles. Variations in porosity, cross-sectional area, anatomic and principal moments of inertia were assessed at 2.5-5.0% increments along the length of the clavicles. The clavicle's biomechanical behavior (axial, flexural, and torsional rigidities and the critical force for buckling) was modeled from these data using beam theory. Over threefold variations in porosity and moments of inertia were found along the length of the s-shaped clavicle--the greatest porosity and moments of inertia were located in the variably shaped sternal and acromial thirds of the bone in contrast to the denser and smaller, more circulatory shaped central third of the bone. Clavicle orientation, as indicated by the direction of greatest resistance to bending (maximum principal moment of inertia), was found to rotate from a primarily cranio-caudal orientation at the sternum to a primarily anterior-posterior orientation at the acromion. Based on cross-sectional geometry, section moduli, and estimates of flexural and torsional rigidity, the clavicle was found to be weakest in the central third of its length. These data concur with the fracture location most commonly reported clinically. Analysis of Euler buckling predicted a minimum critical force for buckling during axial loading of approximately two to three body weights for an average adult. Thus, buckling, or a combination of axial loading and bending or torsional loading, must be considered as possible failure mechanisms for this commonly injured bone.
使用图像处理系统对15例成年男性和女性的人类锁骨进行组织形态计量学特性检查。沿着锁骨长度以2.5 - 5.0%的增量评估孔隙率、横截面积、解剖学和主惯性矩的变化。利用梁理论从这些数据对锁骨的生物力学行为（轴向、弯曲和扭转刚度以及屈曲临界力）进行建模。沿着S形锁骨的长度发现孔隙率和惯性矩有超过三倍的变化——最大的孔隙率和惯性矩位于形状各异的胸骨端和肩峰端三分之一处，而与之形成对比的是，骨头更致密、更小且更呈圆形的中间三分之一处。发现锁骨的方向，如通过最大抗弯方向（最大主惯性矩）所示，从胸骨处主要的颅尾方向旋转到肩峰处主要的前后方向。基于横截面几何形状、截面模量以及弯曲和扭转刚度估计，发现锁骨在其长度的中间三分之一处最弱。这些数据与临床上最常报道的骨折部位一致。对欧拉屈曲的分析预测，对于平均成年人，轴向加载时屈曲的最小临界力约为两到三倍体重。因此，屈曲，或轴向加载与弯曲或扭转加载的组合，必须被视为这种常见受伤骨头可能的失效机制。
