McMahon J M, Boyde A, Bromage T G
Department of Anthropology, Hunter College, C.U.N.Y., NY 10021, USA.
Anat Rec. 1995 Jun;242(2):147-58. doi: 10.1002/ar.1092420203.
Gebhardt (1905. Arch. Entwickl. Org., 20:187-322) originated the hypothesis that the direction of collagen fibers in bone is a structural response to the type of mechanical load to which the bone is subjected. He proposed that collagen fibers aligned parallel to the loading axis are best suited to withstand tensile strain, whereas fibers oriented perpendicular to the loading axis are best able to resist compressive strain. Research comparing load patterns with fiber alignment in bone have tended to support Gebhardt's hypothesis. The aim of the present study is to further test this hypothesis by assessing the correspondence between the distribution of strain and the distribution of collagen fiber orientation in a bone that is subjected to compound loading (i.e., both tension and compression at different phases during the loading cycle). The ovine calcaneum was selected to meet this criterion.
Calcaneum surface strain distributions were obtained from experimental results reported by Lanyon (1973. J. Biomech. 6:41-49). Histological sections of the calcaneal shaft were prepared and observed using circularly polarized light (CPL) microscopy to determine the distribution of collagen fiber alignment. The observed alignment pattern was then compared with the predicted pattern based on Gebhardt's hypothesis.
Contrary to previous studies, our findings show no clear correspondence between the strain type of greatest magnitude and the direction of collagen fibers. Areas of bone characterized by high compression and low tension showed predominantly longitudinal collagen alignment (contra to Gebhardt).
It is argued that even small magnitudes of tension operating on local areas of bone may be sufficient to induce collagen alignment favorable to this type of strain, even when greater magnitudes of compressive strain are acting on the same bone volume.
格布哈特（1905年，《发育器官学文献》，20:187 - 322）提出了一个假说，即骨中胶原纤维的方向是对骨所承受的机械负荷类型的一种结构反应。他提出，与负荷轴平行排列的胶原纤维最适合承受拉伸应变，而与负荷轴垂直排列的纤维最能抵抗压缩应变。比较骨中负荷模式与纤维排列的研究倾向于支持格布哈特的假说。本研究的目的是通过评估在承受复合负荷（即在负荷周期的不同阶段既有张力又有压缩）的骨中应变分布与胶原纤维取向分布之间的对应关系，进一步检验这一假说。选择绵羊跟骨来满足这一标准。
跟骨表面应变分布是根据兰扬（1973年，《生物力学杂志》，6:41 - 49）报道的实验结果获得的。制备跟骨骨干的组织学切片，并使用圆偏振光（CPL）显微镜进行观察，以确定胶原纤维排列的分布。然后将观察到的排列模式与基于格布哈特假说的预测模式进行比较。
与先前的研究相反，我们的研究结果表明，最大应变类型与胶原纤维方向之间没有明显的对应关系。以高压缩和低张力为特征的骨区域主要显示纵向胶原排列（与格布哈特的观点相反）。
有人认为，即使作用于骨局部区域的张力幅度很小，也可能足以诱导有利于这种应变类型的胶原排列，即使在相同骨体积上作用着更大幅度的压缩应变。
