Mechanical Characterization of Human Fascia Lata: Uniaxial Tensile Tests from Fresh-Frozen Cadaver Samples and Constitutive Modelling

Abstract

Human Fascia Lata (FL) is a connective tissue with a multilayered organization also known as aponeurotic fascia. FL biomechanics is influenced by its composite structure formed by fibrous layers (usually two) separated by loose connective tissue. In each layer, most of the collagen fibers run parallel in a distinct direction (with an interlayer angle that usually ranges from 75–80°), mirroring the fascia’s ability to adapt and withstand specific tensile loads. Although FL is a key structure in several musculoskeletal dysfunctions and in tissue engineering, literature still lacks the evidence that proves tissue anisotropy according to predominant collagen fiber directions. For this purpose, this work aims to analyze the biomechanical properties of ex-vivo FL (collected from fresh-frozen human donors) by performing uniaxial tensile tests in order to highlight any differences with respect to loading directions. The experimental outcomes showed a strong anisotropic behavior in accordance with principal collagen fibers directions, which characterize the composite structure. These findings have been implemented to propose a first constitutive model able to mimic the intra- and interlayer interactions. Both approaches could potentially support surgeons in daily practices (such as graft preparation and placement), engineers during in silico simulation, and physiotherapists during musculoskeletal rehabilitation, to customize a medical intervention based on each specific patient and clinical condition.

Ultrasound Imaging of Thoracolumbar Fascia Thickness: Chronic Non-Specific Lower Back Pain versus Healthy Subjects; A Sign of a “Frozen Back”?

“…Moreover, these findings extend those about the anisotropic behavior of fasciae [ 33 ], confirming how a healthy TLF has a good adaptive capacity that is different in multiple directions of movement [ 34 ]. According to our data, the patients with chronic non-specific LBP lost TLF anisotropy, with it becoming homogeneously thicker.…”

“…According to our data, the patients with chronic non-specific LBP lost TLF anisotropy, with it becoming homogeneously thicker. The aponeurotic fasciae, as with the TLF, are usually more rigid in the longitudinal direction, working as a tendon, connecting different body segments and different muscles, and being more adaptable in the transversal direction [ 34 ]. This behavior allows the adaptability of the fasciae to the volume variation of the underlying muscles.…”

Mechanical Characterization of the Male Lower Urinary Tract: Comparison among Soft Tissues from the Same Human Case Study

“…This region corresponded to specific strain ranges according to the tissue: for the bladder [19.42-29.99]%, for the Buck's fascia [13.05, 22.91]%, for the prostate [23.63-19.48]% along the longitudinal direction while [52.51-68.32]% along the transversal one and for the tunica albuginea [9.03, 19.04]% along the longitudinal direction and [10.52-19.02]% along the transversal one. E was then defined as the slope of these regions, computed by means of linear fitting (R 2 > 0.99), as performed in other studies [24,25].…”

Not All Porcine Intestinal Segments Are Equal in Terms of Breaking Force, but None Were Associated to Allometric Parameters

“…We did not aim for a complete and detailed description of porcine intestinal segments with respect to their biomechanical details. At first, this would have required an exact assessment of the specimen thickness, because changes in the sample size would affect the measurements and thus result in an incorrect assessment of the mechanical properties of the specimens [82,83]. Consequently, rectangular specimens cut out of the organs had been used regularly, because they allowed for uni-and biaxial tensile testing with parallel measurement of specimen deformation [84][85][86], as, for example, depicted in detail by Sommer and colleagues [87].…”