Bonnan Matthew F, Crisp Lexi Moore, Barton Ashley, Dizinno Jenna, Muller Kelly, Smith Justine, Walker Jenna
Biology Program, Stockton University, Galloway, New Jersey, USA.
Science Department, Cabrini University, Radnor, Pennsylvania, USA.
Anat Rec (Hoboken). 2025 Aug;308(8):2173-2193. doi: 10.1002/ar.25588. Epub 2024 Oct 14.
The functional morphology and kinematics of the elbow joint remain relatively understudied in squamates. Previous investigations of lizard elbow morphology and kinematics suggest long-axis rotation (LAR) of the radius and ulna during stance allows the manus to remain pronated during forelimb retraction. Using XROMM (X-ray Reconstruction of Moving Morphology), we explored the range of 3D movements and kinematics of the humerus, radius, and ulna in three adult male Central bearded dragons (Pogona vitticeps) during trackway walking. Our data indicate that the elbow joint of P. vitticeps experiences significant rotations in all three dimensions and that the radius and ulna adduct and rotate laterally on their long axes relative to the elbow joint and to one another during stance. These movements allow the distal ends of the radius and ulna to remain in a configuration necessary for manus pronation. These data support previous inferences that the radius and ulna of lizards move independently at the wrist joint. We suggest that independent LAR of the radius and ulna relative to the elbow joint and to one another may be an ancestral mechanism in lizards and perhaps more broadly across non-avian reptiles.
在有鳞目动物中，肘关节的功能形态学和运动学研究相对较少。先前对蜥蜴肘部形态学和运动学的研究表明，在站立时桡骨和尺骨的长轴旋转（LAR）可使手部在肢体回缩过程中保持旋前状态。利用XROMM（运动形态的X射线重建）技术，我们探究了三只成年雄性中部鬃狮蜥（鬃狮蜥）在轨道行走过程中肱骨、桡骨和尺骨的三维运动范围和运动学情况。我们的数据表明，鬃狮蜥的肘关节在所有三个维度上都有显著的旋转，并且在站立时，桡骨和尺骨相对于肘关节以及彼此在其长轴上内收并横向旋转。这些运动使桡骨和尺骨的远端保持在手部旋前所必需的构型。这些数据支持了先前的推断，即蜥蜴的桡骨和尺骨在腕关节处独立运动。我们认为，桡骨和尺骨相对于肘关节以及彼此的独立长轴旋转可能是蜥蜴，或许更广泛地说，是所有非鸟类爬行动物的一种原始机制。
