The close association between muscle and bone is broadly intuitive; however, details of the covariation between the two has not been comprehensively studied. Without quantitative understanding of how muscle anatomy influences bone shape, it is difficult to draw conclusions of the significance of many morphological traits of the skeleton. In this study, we investigated these relationships in the Quenda (Isoodon fusciventer), a scratch‐digging marsupial. We quantified the relationships between forelimb muscle anatomy and bone shape for animals representing a range of body masses (124–1,952 g) using two‐block partial least square analyses. Muscle anatomy was quantified as muscle mass and physiological cross‐sectional area (PCSA), and we used two morphometric methods to characterize bone shape: seven indices of linear bone proportions, and landmarks analysis. Bone shape was significantly correlated with body mass, reflecting allometric bone growth. Of the seven bone indices, only shoulder moment index (SMI) and ulna robustness index (URI) showed a significant covariation with muscle anatomy. Stronger relationships between muscle anatomy and forelimb bone shape were found using the landmark coordinates: muscle mass and PCSA were correlated with the geometric shape of the scapula, humerus, and third metacarpal, but to a lesser extent with shape of the ulna. Overall, our data show that landmark coordinates are more sensitive than bone indices to capturing shape changes evident throughout ontogeny, and is therefore a more appropriate method to investigate covariation with forelimb muscle anatomy. Single‐species studies investigating ontogeny require refined methods to accurately develop understanding of the important relationships between muscle force generation and bone shape remodeling. Landmark analyses provide such a method.

中文翻译：

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澳大利亚划痕有袋动物前肢肌肉解剖与骨骼形状的协变：形态测量方法的比较

肌肉和骨骼之间的密切关联在很大程度上是直观的；然而，尚未对两者之间的协变细节进行全面研究。如果不定量了解肌肉解剖结构如何影响骨骼形状，就很难得出骨骼许多形态特征的重要性的结论。在这项研究中，我们调查了 Quenda (Isoodon fusciventer) 中的这些关系，这是一种抓挠有袋动物。我们使用双区组偏最小二乘分析量化了代表一系列体重 (124–1,952 g) 的动物的前肢肌肉解剖结构与骨骼形状之间的关系。肌肉解剖被量化为肌肉质量和生理横截面积 (PCSA)，我们使用两种形态测量方法来表征骨骼形状：线性骨骼比例的七个指数，和地标分析。骨骼形状与体重显着相关，反映了异速骨骼生长。在七个骨骼指数中，只有肩力矩指数 (SMI) 和尺骨健壮指数 (URI) 显示出与肌肉解剖结构的显着协变。使用标志性坐标发现肌肉解剖结构和前肢骨骼形状之间更强的关系：肌肉质量和 PCSA 与肩胛骨、肱骨和第三掌骨的几何形状相关，但与尺骨的形状相关程度较小。总体而言，我们的数据表明，地标坐标比骨骼指数更敏感地捕捉整个个体发育过程中明显的形状变化，因此是一种更合适的方法来研究与前肢肌肉解剖结构的共变。调查个体发育的单一物种研究需要改进的方法来准确地理解肌肉力生成和骨骼形状重塑之间的重要关系。地标分析提供了这样一种方法。