Murray W M, Delp S L, Buchanan T S
Department of Biomedical Engineering, Northwestern University, Chicago, IL, USA.
J Biomech. 1995 May;28(5):513-25. doi: 10.1016/0021-9290(94)00114-j.
We hypothesized that the moment arms of muscles crossing the elbow vary substantially with forearm and elbow position and that these variations could be represented using a three-dimensional computer model. Flexion/extension and pronation/supination moment arms of the brachioradialis, biceps, brachialis, pronator teres, and triceps were calculated from measurements of tendon displacement and joint angle in two anatomic specimens and were estimated using a computer model of the elbow joint. The anatomical measurements revealed that the flexion/extension moment arms varied by at least 30% over a 95 degrees range of motion. The changes in flexion/extension moment arm magnitudes with elbow flexion angle were represented well by the computer model. The anatomical studies and the computer model demonstrate that the biceps flexion moment arm peaks in a more extended elbow position and has a larger peak when the forearm is supinated. Also, the peak biceps supination moment arm decreases as the elbow is extended. These results emphasize the need to account for the variation of muscle moment arms with elbow flexion and forearm position.
我们假设，跨越肘部的肌肉的力臂会随着前臂和肘部位置的变化而大幅改变，并且这些变化可以用三维计算机模型来呈现。通过对两个解剖标本中肌腱位移和关节角度的测量，计算出了肱桡肌、肱二头肌、肱肌、旋前圆肌和肱三头肌的屈伸和旋前/旋后力臂，并使用肘关节计算机模型进行了估算。解剖测量结果显示，在95度的运动范围内，屈伸力臂至少变化了30%。计算机模型很好地呈现了屈伸力臂大小随肘关节屈曲角度的变化。解剖学研究和计算机模型表明，肱二头肌的屈曲力臂在肘关节更伸展的位置达到峰值，并且当前臂旋后时峰值更大。此外，随着肘关节伸展，肱二头肌旋后力臂的峰值会降低。这些结果强调了需要考虑肌肉力臂随肘关节屈曲和前臂位置的变化。
