The relative contributions of multiarticular snake muscles to movement in different planes
The relative contributions of multiarticular snake muscles to movement in different planes
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DOI：
10.1002/jmor.21591
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发表时间：
2023-06-01
影响因子：
1.5
通讯作者：
Astley，Henry C.
中科院分区：
文献类型：
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作者：
Tingle，Jessica L.;Jurestovsky，Derek J.;Astley，Henry C.
跨越多个关节的肌肉在四足动物的广泛系统中发挥着重要的功能作用;然而，它们的基本力学机制却知之甚少，特别是解剖位置对机械优势的影响。蛇为推进这一主题提供了一个很好的研究系统。它们依靠中轴肌进行许多活动，包括攻击、收缩、防御展示和运动。此外，这些肌肉的跨度从一个或几个椎骨到30多个，肌肉和物种之间的解剖结构各不相同。我们使用diceCT扫描描述了玉米蛇（Pantherophis guttatus）大小系列中主要轴上肌肉的解剖结构，然后采用几种方法来计算每个肌肉对身体弯曲过程中产生的力和运动的贡献，从高度简单化的模型开始，并转向越来越复杂和逼真的模型。只有最现实的模型才能产生包括肌肉跨度对扭矩-位移权衡的影响的方程，并解决更简单模型产生的模糊性。我们还测试了肌肉横截面积或杠杆臂（总幅度或俯仰/偏航/滚转分量）是否与蛇质量、纵向身体区域（前、中、后）和/或肌肉群（半棘肌-棘肌、多裂肌、背最长肌、髂肋肌和肋提肌）相关。肌肉横截面积通常与正异速生长成比例，大多数杠杆臂没有显著偏离几何相似性（等距）。肋提肌的横截面积低于四块轴上肌，这四块肌在横截面积上没有显著差异。杠杆臂的总幅度和组件不同的肌肉。我们发现了一些区域差异的证据，表明功能区划值得进一步研究。我们的研究结果有助于了解蛇的肌肉，特别是多关节肌肉系统一般，提供了一个基础，为未来的比较物种和生物启发的多关节系统。
Muscles spanning multiple joints play important functional roles in a wide range of systems across tetrapods; however, their fundamental mechanics are poorly understood, particularly the consequences of anatomical position on mechanical advantage. Snakes provide an excellent study system for advancing this topic. They rely on the axial muscles for many activities, including striking, constriction, defensive displays, and locomotion. Moreover, those muscles span from one or a few vertebrae to over 30, and anatomy varies among muscles and among species. We characterized the anatomy of major epaxial muscles in a size series of corn snakes (Pantherophis guttatus) using diceCT scans, and then took several approaches to calculating contributions of each muscle to force and motion generated during body bending, starting from a highly simplistic model and moving to increasingly complex and realistic models. Only the most realistic model yielded equations that included the consequence of muscle span on torque‐displacement trade‐offs, as well as resolving ambiguities that arose from simpler models. We also tested whether muscle cross‐sectional areas or lever arms (total magnitude or pitch/yaw/roll components) were related to snake mass, longitudinal body region (anterior, middle, posterior), and/or muscle group (semispinalis‐spinalis, multifidus, longissimus dorsi, iliocostalis, and levator costae). Muscle cross‐sectional areas generally scaled with positive allometry, and most lever arms did not depart significantly from geometric similarity (isometry). The levator costae had lower cross‐sectional area than the four epaxial muscles, which did not differ significantly from each other in cross‐sectional area. Lever arm total magnitudes and components differed among muscles. We found some evidence for regional variation, indicating that functional regionalization merits further investigation. Our results contribute to knowledge of snake muscles specifically and multiarticular muscle systems generally, providing a foundation for future comparisons across species and bioinspired multiarticular systems.