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首页> 外文期刊>Journal of Biomechanics >Wall thickness of gas- and marrow-filled avian long bones: Measurements on humeri, femora and tibiotarsi in crows (Corvus corone cornix) and magpies (Pica pica).
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Wall thickness of gas- and marrow-filled avian long bones: Measurements on humeri, femora and tibiotarsi in crows (Corvus corone cornix) and magpies (Pica pica).

机译：充满气体和骨髓的禽类长骨的壁厚：测量乌鸦（Corvus corone cornix）和喜pies（Pica pica）中的肱骨，股骨和胫骨tar。

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摘要

We studied how the ratio K of the internal to external diameter of gas- and marrow-filled avian long bones follows the biomechanical optima derived for tubular bones with minimum mass designed to fulfil various mechanical requirements. We evaluated radiographs of numerous humeri, femora and tibiotarsi in Corvus corone cornix and Pica pica. The K-values of the gas-filled humerus (K=0.78+/-0.03) and the marrow-filled femur (K=0.79+/-0.02) in Corvus are practically the same, while K of the marrow-filled tibiotarsus (K=0.71+/-0.04) is significantly smaller. The same is true for the gas-filled humerus (K=0.78+/-0.02) and the marrow-filled femur (K=0.77+/-0.02) and tibiotarsus (K=0.67+/-0.05) in Pica. K in Corvus is slightly larger than K in Pica, but the differences are statistically not significant. The standard deviation DeltaK of the tibiotarsi (DeltaK=0.04-0.05) is approximately two times as large as that of the humeri (DeltaK=0.02-0.03) and femora (DeltaK=0.02) in both species. Accepting the assumptionof earlier authors that the ratio Q of the marrow to bone density is 0.5, our data show that the marrow-filled tibiotarsi of Corvus and Pica are optimized for stiffness, while the marrow-filled femora are far from any optimum. The relative wall thickness W=1-K of the gas-filled avian humeri studied is much larger than the theoretical optimum W*=1-K*=0.07, and thus these bones are thicker-walled than the optimal gas-filled tubular bone with minimum mass.
机译：我们研究了充满气体和骨髓的禽类长骨的内径与外径之比K如何遵循为满足各种机械要求而设计的最小质量的管状骨的生物力学最佳值。我们对Corvus corone cornix和Pica pica中的许多肱骨，股骨和胫骨tar进行了放射线照相。乌鸦座中充满气体的肱骨（K = 0.78 +/- 0.03）和充满骨髓的股骨（K = 0.79 +/- 0.02）的K值几乎相同，而充满骨髓的胫骨的K值（ K = 0.71 +/- 0.04）明显较小。 Pica中充满气体的肱骨（K = 0.78 +/- 0.02）和充满骨髓的股骨（K = 0.77 +/- 0.02）和胫骨tar骨（K = 0.67 +/- 0.05）也是如此。乌鸦座中的K略大于皮卡中的K，但差异在统计学上不显着。在两个物种中，胫骨tar骨的标准偏差DeltaK（DeltaK = 0.04-0.05）大约是肱骨（DeltaK = 0.02-0.03）和股骨（DeltaK = 0.02）的两倍。接受先前作者的假设，即骨髓与骨密度之比Q为0.5，我们的数据表明，Corvus和Pica的充满骨髓的胫骨tar对刚度进行了优化，而充满股骨的骨髓远非最佳。所研究的充气禽肱骨的相对壁厚W = 1-K远大于理论最佳W * = 1-K * = 0.07，因此这些骨头的壁厚比最佳充气管状鱼骨更厚以最小的质量。

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