Functional Anatomy
James Crossley in Functional Exercise and Rehabilitation, 2021
Skeletal muscle is composed of many individual muscle fibers wrapped together in bundles. Connective tissue known as fascia covers each of these bundles. The outer layer that covers the whole muscle is called the epimysium. The epimysium runs into tendon of the muscle that attaches and transmits force to the bone. Muscles attach to bone proximally (origin) and distally (insertion). Origin – muscle attachment that is generally more proximal and moves the leastInsertion – muscle attachment that is generally more distal and moves the most Under the epimysium we see bundles of muscle fibers known as the fascicles, wrapped in fascia called the perimysium. Each muscle fiber is wrapped in a connective tissue called the endomysium. Each muscle fiber forms the building blocks of muscle called myofibrils.
Fascial Anatomy
David Lesondak, Angeli Maun Akey in Fascia, Function, and Medical Applications, 2020
Aponeurotic fasciae envelope and connect whole groups of muscles. It covers the extremity muscles and includes both the thoracolumbar fascia (TLF) and the rectus abdominal sheath (RAS) in the torso. Epimysial fasciae covers and adheres to the whole muscle and can be used to refer to all the intramuscular connective tissue, which includes the epimysium, perimysium, and endomysium. Because it is so intertwined with the muscle tissue, it is not possible to separate the epymysial fascia from the muscle. It is in continuity, and the function of one is strongly dependent on the other. In the extremities and in some parts of the trunk, such as the TLF and RAS, the aponeurotic fascia slides over the epimysium that covers the muscle and continues around the tendon (epitenon). Both epimysial fascia and epimysium proper transmit the force of the muscle to the surrounding areas thanks to myofascial expansions, but they have different thickness. Epimysial fascia is thicker, between 0.5 and 0.9 mm, whereas the epimysium is thinner, less than 0.1 mm. Both aponeurotic fasciae and epimysial fascia transmit the forces of muscle contraction. Closely associated with the epimysium is the perimysium, which covers the muscle fiber bundles and is in continuity with the endomysium located around every single muscle fiber.
Fascial Syndromes
Kohlstadt Ingrid, Cintron Kenneth in Metabolic Therapies in Orthopedics, Second Edition, 2018
While anatomy books like to divide fascia into discrete units and aggregates, it is vital to remember that all these parts, pieces and layers are part of one system. Starting just under the skin with the more superficial or areolar layer to the deep fascia or fascia profunda. The deep fascia comprises all the layers that interact with the musculoskeletal body (Figure 21.2). The deep fascia is highly organized and very much like an elastic, full-length body stocking – the innermost layer peeling away to form an epimysium, a pocket around each muscle. These epimysial pockets are free to glide due to hyaluronan [5]. This layer continues to the bundled perimysium, down to each individual muscle fiber wrapped in its own endomysium. This honeycomb arrangement allows for load sharing among the individual myofibers. Electron microscope studies have also revealed collagen fibers running in a more perpendicular fashion, creating a longitudinal network through the epimysium to the adjacent antagonistic muscle [16]. Other imaging studies clearly show the collagen fibers getting smaller and smaller, going all the way down to and through individual cell walls [17].
Modeling of muscular activation of the muscle-tendon complex using discrete element method
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2021
Anthony Roux, Jennyfer Lecompte, Ivan Iordanoff, Sébastien Laporte
The mechanical properties and structures of the MTC model were described in Roux et al. (2016) (Figure 5). Numerical model was complete in DEM using GranOO software (www.granoo.org). Mechanical properties of MTC were based on values from the literature (Matschke et al. 2013, Regev et al. 2011). Fibers were built with spherical discrete elements, to model the inertia effects, linked by springs, to model the rheological behavior (stiffness was related to Young’s modulus: fiber’s Young’s modulus = 37.44 kPa). Tendon fibers were built in accordance with the arrangement of finger-like muscle fibers, inserted into the muscle to represent the myo-tendinous junction (MTJ) (Roux et al. 2016) (tendon’s Young’s modulus = 800 MPa, MTJ’s Young’s modulus = 400 MPa). Links are also created between fibers themselves and between tendon’s fibers and the epimysium (same Young’s modulus as tendon’s fibers) in order to simulate sliding between these two entities. The extracellular matrix (ECM) was computed using springs between fibers in all directions (ECM’s Young’s modulus = 0.1 MPa). For further information, the reader can refer to Roux et al. 2016.
Superficial CD34-Positive Fibroblastic Tumor on the Chest Wall of an 8-Year-Old Girl: A Case Report and Literature Review
Published in Pediatric Hematology and Oncology, 2021
Si Ying Li, Hai Lan Zhang, Yu Zuo Bai
An 8-year-old girl was admitted to our hospital 4 months after a tumor was detected on her left chest wall. The patient’s symptoms had started 4 months earlier with a mild tenderness mass on the left chest wall without irritation or inflammatory manifestations such as redness, swelling, or fever. The tumor was approximately the size of a fingernail and grew slowly. During physical examination, an enclosed solid mass with size of 1.5 × 1.0 × 1.0 cm was detected on the left chest wall, at approximately the level of the 8th to 9th rib, with a clear border. Imaging examination by ultrasonography showed a hypoechoic enclosed mass on the epimysium layer of left chest wall. The mass was 0.9 × 0.7 × 0.6 cm in size. No obvious blood flow signal was detected by Color Doppler Flow Imaging (CDFI) (Figure 1A).
Metalloproteinases in disease: identification of biomarkers of tissue damage through proteomics
Published in Expert Review of Proteomics, 2018
Cristina Herrera, Teresa Escalante, Alexandra Rucavado, Jay W. Fox, José María Gutiérrez
Exudate proteomic analysis from mice injected with SVMPs also underscored the presence of fragments of types XII, XIV and XV collagens. The former two are fibril-associated collagens with interrupted triple helices (FACITs) and play a role in the supramolecular organization of fibrillar collagens [91]. In skeletal muscle, these FACITs connect muscle BM with the connective tissue components of epimysium and perimysium [92,93]. Type XV collagen, on the other hand, acts as a BM organizer [94]. Both types VI and XV collagens are degraded to a higher extent by hemorrhagic SVMPs than by non-hemorrhagic enzymes, suggesting that their hydrolysis might be implicated in the mechanical weakening of the capillary wall which causes hemorrhage [58]. Figure 5 summarizes the main targets of SVMPs in the BM and surrounding matrix components.
Related Knowledge Centers
- Collagen
- Fascia
- Muscle
- Endomysium
- Skeletal Muscle
- Dense Irregular Connective Tissue
- Perimysium