Biomechanical Properties of Fascial Tissues and Their Role as Pain Generators

ABSTRACT

Objectives: To highlight the load bearing functions of fascial tissues and their proneness to micro tearing during physiological or excessive loading, to review histological evidence for a proprioceptive as well as nociceptive innervation of fascia, and to emphasize the potential role of injury, inflammation, and/or neural sensitization of the posterior layer of the human lumbar fascia in non-specific low back pain.

Findings: In addition to a tensional load bearing function of tendons and ligaments, muscles transmit a significant portion of their force via their epimysia to laterally positioned tissues, such as to synergistic or antagonistic muscles. Fascial tissues are commonly used as elastic springs [catapult action] during oscillatory movements, such as walking, hopping, or running, in which the supporting skeletal muscles contract rather isometrically. They are prone to viscoelastic deformations such as creep, hysteresis, and relaxation. Such temporary deformations alter fascial stiffness and may take several hours for recovery. There is a gradual transition zone between reversible viscoelastic deformation and complete tissue tearing. Micro tearing of collagenous fibers and their interconnections have been documented in this zone. Fascia is densely innervated by myelinated nerve endings which are assumed to serve a proprioceptive function. These are Pacini [and paciniform] corpuscles, Golgi tendon organs, and Ruffini endings. In addition they are innervated by free endings, containing substance P, suggestive of a nociceptive function. New findings suggest that noicipetive activity of epimysial fasciae play a major role in delayed onset muscle soreness subsequent to repetitive concentric exercise.

Conclusions: Fascial tissues serve important load bearing functions. The innervation of fascia indicates a sensory role as an organ for propriocepton, and also a potential nociceptive function. Micro tearing and/or inflammation of fascia can be a direct source of musculoskeletal pain. Fascia may be an indirect source of back pain.

KEYWORDS. :

• Myofibroblasts
• fascial tonicity
• delayed onset muscle soreness [DOMS]
• fascial innervation
• micro tearing