Bishop Peter J, Clemente Christofer J, Hocknull Scott A, Barrett Rod S, Lloyd David G
Geosciences Program, Queensland Museum, Brisbane, Qld, Australia.
School of Allied Health Sciences, Griffith University, Southport, Qld, Australia.
J Anat. 2017 Mar;230(3):461-470. doi: 10.1111/joa.12569. Epub 2016 Nov 29.
Cancellous bone is very sensitive to its prevailing mechanical environment, and study of its architecture has previously aided interpretations of locomotor biomechanics in extinct animals or archaeological populations. However, quantification of architectural features may be compromised by poor preservation in fossil and archaeological specimens, such as post mortem cracking or fracturing. In this study, the effects of post mortem cracks on the quantification of cancellous bone fabric were investigated through the simulation of cracks in otherwise undamaged modern bone samples. The effect on both scalar (degree of fabric anisotropy, fabric elongation index) and vector (principal fabric directions) variables was assessed through comparing the results of architectural analyses of cracked vs. non-cracked samples. Error was found to decrease as the relative size of the crack decreased, and as the orientation of the crack approached the orientation of the primary fabric direction. However, even in the best-case scenario simulated, error remained substantial, with at least 18% of simulations showing a > 10% error when scalar variables were considered, and at least 6.7% of simulations showing a > 10° error when vector variables were considered. As a 10% (scalar) or 10° (vector) difference is probably too large for reliable interpretation of a fossil or archaeological specimen, these results suggest that cracks should be avoided if possible when analysing cancellous bone architecture in such specimens.
松质骨对其所处的力学环境非常敏感，对其结构的研究此前有助于解读已灭绝动物或考古群体的运动生物力学。然而，化石和考古标本保存不佳，如死后出现裂纹或断裂，可能会影响结构特征的量化。在本研究中，通过模拟未受损的现代骨样本中的裂纹，研究了死后裂纹对松质骨结构量化的影响。通过比较有裂纹和无裂纹样本的结构分析结果，评估了对标量变量（结构各向异性程度、结构伸长指数）和矢量变量（主要结构方向）的影响。结果发现，随着裂纹相对尺寸的减小以及裂纹方向接近主要结构方向的取向，误差会降低。然而，即使在模拟的最佳情况下，误差仍然很大，在考虑标量变量时，至少18%的模拟显示误差>10%，在考虑矢量变量时，至少6.7%的模拟显示误差>10°。由于10%（标量）或10°（矢量）的差异可能太大，无法可靠地解读化石或考古标本，这些结果表明，在分析此类标本的松质骨结构时，应尽可能避免出现裂纹。
