Department of Mechanical Engineering, Bucknell University, Lewisburg, PA.
Musculoskeletal Institute, Geisinger, Danville, PA.
Acta Biomater. 2023 Sep 15;168:298-308. doi: 10.1016/j.actbio.2023.06.035. Epub 2023 Jun 30.
Aponeurosis is a sheath-like connective tissue that aids in force transmission from muscle to tendon and can be found throughout the musculoskeletal system. The key role of aponeurosis in muscle-tendon unit mechanics is clouded by a lack of understanding of aponeurosis structure-function properties. This work aimed to determine the heterogeneous material properties of porcine triceps brachii aponeurosis tissue with materials testing and evaluate heterogeneous aponeurosis microstructure with scanning electron microscopy. We found that aponeurosis may exhibit more microstructural collagen waviness in the insertion region (near the tendon) compared to the transition region (near the muscle midbelly) (1.20 versus 1.12, p = 0.055), which and a less stiff stress-strain response in the insertion versus transition regions (p < 0.05). We also showed that different assumptions of aponeurosis heterogeneity, specifically variations in elastic modulus with location can alter the stiffness (by more than 10x) and strain (by approximately 10% muscle fiber strain) of a finite element model of muscle and aponeurosis. Collectively, these results suggest that aponeurosis heterogeneity could be due to variations in tissue microstructure and that different approaches to modeling tissue heterogeneity alters the behavior of computational models of muscle-tendon units. STATEMENT OF SIGNIFICANCE: Aponeurosis is a connective tissue found in many muscle tendon units that aids in force transmission, yet little is known about the specific material properties of aponeurosis. This work aimed to determine how the properties of aponeurosis tissue varied with location. We found that aponeurosis exhibits more microstructural waviness near the tendon compared to near the muscle midbelly, which was associated with differences in tissue stiffness. We also showed that different variations in aponeurosis modulus (stiffness) can alter the stiffness and stretch of a computer model of muscle tissue. These results show that assuming uniform aponeurosis structure and modulus, which is common, may lead to inaccurate models of the musculoskeletal system.
腱膜是一种类似鞘的结缔组织,有助于将力从肌肉传递到肌腱,并存在于整个肌肉骨骼系统中。腱膜在肌肉-肌腱单位力学中的关键作用因对腱膜结构-功能特性缺乏了解而变得模糊不清。这项工作旨在通过材料测试确定猪三头肌腱膜组织的不均匀材料特性,并通过扫描电子显微镜评估不均匀腱膜微观结构。我们发现,与过渡区(靠近肌肉中腹部)相比,腱膜在插入区(靠近肌腱)可能表现出更多的微观胶原波纹(1.20 比 1.12,p=0.055),并且在插入区的应力-应变响应比过渡区更软(p<0.05)。我们还表明,腱膜异质性的不同假设,特别是弹性模量随位置的变化,会改变肌肉和腱膜有限元模型的刚度(超过 10 倍)和应变(大约 10%肌肉纤维应变)。总的来说,这些结果表明腱膜的异质性可能是由于组织微观结构的变化,而对组织异质性建模的不同方法会改变肌肉-肌腱单元计算模型的行为。
腱膜是一种存在于许多肌肉-肌腱单元中的结缔组织,有助于力的传递,但人们对腱膜的具体材料特性知之甚少。这项工作旨在确定腱膜组织的特性如何随位置而变化。我们发现,与靠近肌肉中腹部相比,腱膜在靠近肌腱处表现出更多的微观波纹,这与组织刚度的差异有关。我们还表明,腱膜模量(刚度)的不同变化可以改变肌肉组织计算机模型的刚度和拉伸。这些结果表明,假设常见的均匀腱膜结构和模量可能会导致肌肉骨骼系统的不准确模型。