Cutts A, Seedhom B B
Rheumatology and Rehabilitation Research Unit, School of Medicine, University of Leeds, Leeds, UK.
Clin Biomech (Bristol). 1993 May;8(3):156-62. doi: 10.1016/0268-0033(93)90057-O.
Muscle physiological cross-sectional area (PCSA) is calculated from muscle volume, fibre length and fibre pennation angle, and is a measure of force/stress. Muscle force analyses in the human body usually yield combined forces of groups of synergistic muscles rather than individual muscle forces, because of the constraints of statically determinate models. As stresses acting in a group of muscles are uniform, the ratio of the physiological cross-sectional areas of a group of muscles can be used to divide the combined force into its component parts. This paper investigates the validity of the common practice of using cadaveric physiological cross-sectional area to divide in-vivo group muscle forces into component parts. Muscle volumes were determined in vivo using a combination of radiographic techniques for a small number of active young males, and 'in-vivo' physiological cross-sectional areas were calculated using cadaveric data for fibre length and pennation angle. As would be expected, in absolute terms, the 'in-vivo' values were much larger than those of cadavers. Comparison of the percentage contribution of each muscle to the total value of its group showed little difference between the cadaveric and 'in-vivo' data. We conclude that it is reasonable to use cadaveric data when only relative physiological cross-sectional areas are required, more so in the quadriceps than in the hamstrings. Considering data from active young subjects and cadavers, we have shown the ratios of the physiological cross-sectional area of the individual muscles of the quadriceps (and to a lesser extent the hamstrings) to be comparable. This validates the practice of using cadaveric data for relative physiological cross-sectional area in statically determinate force analysis in the human body. 9n-vivo' ratios are also presented for future use.
肌肉生理横截面积（PCSA）由肌肉体积、纤维长度和纤维羽状角计算得出，是力/应力的一种度量。由于静定模型的限制，人体肌肉力分析通常得出协同肌群的合力而非单个肌肉的力。由于作用于一组肌肉的应力是均匀的，一组肌肉的生理横截面积之比可用于将合力分解为其组成部分。本文研究了使用尸体生理横截面积将体内肌群力分解为组成部分这一常见做法的有效性。对于少数活跃的年轻男性，结合放射学技术在体内测定肌肉体积，并使用尸体数据中的纤维长度和羽状角计算“体内”生理横截面积。不出所料，从绝对值来看，“体内”值比尸体的要大得多。比较每块肌肉对其肌群总值的贡献百分比，尸体数据和“体内”数据之间差异不大。我们得出结论，当只需要相对生理横截面积时，使用尸体数据是合理的；对于股四头肌而言比腘绳肌更合理。考虑到来自活跃年轻受试者和尸体的数据，我们已表明股四头肌（在较小程度上也包括腘绳肌）各肌肉的生理横截面积之比具有可比性。这验证了在人体静定力学分析中使用尸体数据获取相对生理横截面积这一做法的合理性。还给出了“体内”比值以供未来使用。
