Directional Differences in the Biaxial Material Properties of Fascia Lata and the Implications for Fascia Function

Abstract

Fascia is a highly organized collagenous tissue that is ubiquitous in the body, but whose function remains an enigma. Because fascia has a sheet-like structure attaching to muscles and bones at multiple sites, it is exposed to different states of multi-or biaxial strain. In order to measure how biaxial strain affects fascia material properties, planar biaxial tests with strain control were performed on longitudinal and transversely oriented samples of goat fascia lata (FL). Cruciform samples were cycled to multiple strain levels while the non-cycling perpendicular direction was held at a constant strain. Structural differences among FL layers were examined using histology and SEM. Results show that FL modulus, hysteresis, and strain energy density are greater in the longitudinal versus transverse direction. Increased stiffness in the longitudinal layer is likely due to its greater thickness and greater average fibril diameter compared to the transverse layer(s). Perpendicular strain did not affect FL material properties.Differential loading in the longitudinal versus transverse directions may lead to structural changes, enhancing the ability of the longitudinal FL to transmit force, store energy, or stabilize the limb during locomotion. The relative compliance of the transverse fibers may allow expansion of underlying muscles when they contract.

A semiautomatic method for in vivo three-dimensional quantitative analysis of fascial layers mobility based on 3D ultrasound scans

“…In the past years, many efforts have been made to develop biomechanical models to assist in deciphering the fascia function and help in understanding how alterations of the deep fascia can result in musculoskeletal disorders and pain [3,18,[46][47][48]. In this context, our approach attempts to contribute to the knowledge of the fascia behavior, by proposing a novel strategy for the assessment in vivo fascial mobility in 3D.…”

The capacity of the human iliotibial band to store elastic energy during running

“…5. Normalized force-length curves for anterior and posterior regions of the ITB derived from experimental data (Butler et al, 1984;Derwin et al, 2008;Eng et al, 2014). Curves are shown for TFL-ITB ant (short dash), GMax1,2-ITB post1 (long dash), and GMax3,4-ITB post2 (dot-dash) with shaded regions indicating 7 20% stiffness used in the sensitivity analysis.…”

“…5) based on published material properties of the human ITB (Butler et al, 1984;Derwin et al, 2008). We assumed a transition strain of 4% based on data from goat fascia lata (Eng et al, 2014). Above 4% strain, we assumed a linear relationship between force and strain with a normalized stiffness k ( ) determined using the ITB's elastic modulus (E), the muscle's F max , and the ITB's effective cross-sectional area (a):…”

“…4). This model represents the muscles as independent, proximal-to-distal MTUs, even though the ITB is multilayered and loaded from different directions, based on detailed dissections and on biaxial testing of goat fascia lata, which showed that the fascia's material properties are not strongly influenced by its biaxial strain environment (Eng et al, 2014).…”

Determination and Finite Element Validation of the WYPIWYG Strain Energy of Superficial Fascia from Experimental Data

“…The mechanical properties of fasciae strongly affect muscular actions and the development of pathologies, such as acute and chronic compartment syndromes. However, very few studies regarding fascia mechanical properties are available and these are mainly focused on the study of the properties of deep fascia [2,3] but not on the properties of superficial fascia [4].…”