Hert J, Fiala P, Petrtýl M
Anatomický ústav LF KU, Plzen.
Acta Chir Orthop Traumatol Cech. 1993;60(4):199-208.
The authors elaborated a new macroscopic method which made it possible to analyze the orientation of osteons in the entire diaphysis. All long bones of the human extremities were thus analyzed. In each bone the osteons are arranged in a specific pattern but according to a uniform plan. Most of them are oriented in an oblique direction and are arranged as two helices of opposite directions located on opposite sides of the bone. The two fields are separated by a sharp borderline. Biomechanical analysis revealed that the orientation of the osteons is consistent with the direction of the maximal principal stress which depends on the normal and torsional stress to which the bone is exposed. From the orientation of osteons the authors derived ex post the mode of dominant loading of all long bones: the femur is exposed to bending in the medial direction and to outer rotation, the tibia is exposed to bending in dorsal direction and to inner rotation. The humerus is bent in the medial direction, the radius in the dorsal one. Both these bones are exposed to loading in inner rotation. In the ulna and fibula the mode of stress could not be assessed by the authors' method. The results are summarized in two diagrams which indicate the orientation of osteons and the way in which the long bones in man are exposed to load. The authors discuss the theoretical and practical impact of these findings.
作者们阐述了一种新的宏观方法，该方法使得分析整个骨干中骨单位的取向成为可能。因此，对人类四肢的所有长骨进行了分析。在每根骨头中，骨单位都按照特定的模式排列，但遵循统一的规律。它们中的大多数呈倾斜方向排列，并形成位于骨头相对两侧的两个相反方向的螺旋。这两个区域由一条清晰的边界线分隔。生物力学分析表明，骨单位的取向与最大主应力方向一致，而最大主应力方向取决于骨头所承受的法向应力和扭转应力。根据骨单位的取向，作者事后推导了所有长骨的主要加载模式：股骨承受向内方向的弯曲和外旋，胫骨承受背侧方向的弯曲和内旋。肱骨向内方向弯曲，桡骨向背侧弯曲。这两块骨头都承受内旋加载。作者的方法无法评估尺骨和腓骨的应力模式。结果总结在两张图表中，这两张图表显示了骨单位的取向以及人类长骨承受负荷的方式。作者们讨论了这些发现的理论和实际影响。
