When vigorous goats are running and jumping, their leg bones play a crucial role in dynamic loading. The hierarchical structure of diverse tissues at different length scales is commonly used to account for the superior mechanical properties of bone. Yet, how the goat tibia achieves its remarkable function remains mostly unknown. Scanning electron microscopy was employed to image the multi-scale microstructure of the cortical bone in goat tibia. A new processing method was utilized during the preparation of one of the three kinds of samples. The transverse and longitudinal sections of the cortical bone were observed thoroughly, and high-quality images of the internal organizations are acquired. Some interesting findings, including the two-layered character of cortical bone and the microstructure near osteocyte lacunae, are discussed. A three-dimensional three-level hierarchical structure is found accordingly. Then, the cushioning mechanisms are discussed by analyzing the structure–function relationships of the bone tissues. Finally, a structural model of biomimetic composite is proposed based on the authors’ insights into the constitution of cortical bone, which is expected to inspire engineers to design load-bearing structures with excellent mechanical performance.

中文翻译：

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山羊胫骨皮质骨微观结构的启示

当有力的山羊奔跑和跳跃时，它们的腿骨在动态负荷中起着至关重要的作用。通常使用不同长度尺度的各种组织的层次结构来说明骨骼的优越机械性能。然而，山羊胫骨如何发挥其卓越的功能仍然未知。使用扫描电子显微镜对山羊胫骨皮质骨的多尺度显微结构进行成像。在三种样品之一的制备过程中采用了一种新的处理方法。彻底观察了皮质骨的横向和纵向截面，并获得了内部组织的高质量图像。讨论了一些有趣的发现，包括皮质骨的两层特征和骨细胞腔的微结构。相应地发现了三维三级分层结构。然后，通过分析骨骼组织的结构-功能关系来讨论缓冲机制。最后，根据作者对皮质骨组成的见解，提出了仿生复合材料的结构模型，有望激发工程师设计出具有优异机械性能的承重结构。