Anatomy · functional reading
Fascial innervation
Fascial innervation refers to the nerve fibers that fascia contains. Made up mainly of free nerve endings that are sensitive to deformation, it informs the nervous system about tissue tension, stretch and pressure, and can contribute to pain.
Scientific basis
A systematic review (Suarez-Rodriguez et al., 2022) confirms the presence of nerve fibers in many fascial structures, with a density that varies by region, depth and study method. The superficial layers and the areas close to blood vessels or attachments are often the most densely innervated.
In the three regions where the comparison has been made, connective or fascial tissue is more densely innervated than the neighboring muscle: about 1.8 times for the connective tissue of the masseter in humans (Alhilou et al., 2021), and about 3 times for the thoracolumbar fascia in mice (Barry et al., 2015). The figures of “six” or “ten times” that circulate do not correspond to measurements.
Deep fascia contains mainly free nerve endings, some of which are nociceptive. Corpuscles (Ruffini, Pacini) have been described in certain fascial structures, such as those of the hand, the foot or the flexor retinaculum, but recent studies do not find them in the thoracolumbar fascia (Tesarz et al., 2011). In volunteers, an injection of hypertonic saline into this fascia causes more intense and longer-lasting pain than an injection into the underlying muscle (Schilder et al., 2014).
Blue Portance / SBNFA™ reading
In the SBNFA™, fascial innervation is read as the interface through which the mechanical state of tissues becomes information for the nervous system: the tension, stretch and pressure that a position imposes are perceived and integrated. The hypothesis that varied mechanical inputs sustain more diverse mechanosensory information than a fixed, unchanging load belongs to the SBNFA™ reading.
Contribution to the analysis of sitting
In the seated position, the fascia of the pelvis and lower back undergoes sustained pressure and stretch. The analysis looks at the duration, location and variability of these loads; it does not make it possible to attribute pain to a fascial origin.
Not to be confused with
Cutaneous tactile receptors (Merkel, Meissner), specialized in fine touch; proprioception, the perception of position and movement, to which fascia contributes among other sources; myofascial pain syndrome, a regional clinical syndrome.
Related terms
Sources and scope
- Suarez-Rodriguez et al. (2022): the innervation of fascia, a systematic review (Int J Mol Sci)
- Alhilou et al. (2021): nerve fiber density of the human masseter muscle (J Oral Rehabil)
- Barry et al. (2015): sensory fibers of the thoracolumbar fascia and back muscles in the mouse (Neuroscience)
- Tesarz et al. (2011): sensory innervation of the thoracolumbar fascia in rats and humans (Neuroscience)
- Schilder et al. (2014): stimulation of the thoracolumbar fascia with hypertonic saline (Pain)
Established but heterogeneous histological data, partly from animal studies. The quantitative contribution of fascia to proprioception and to clinical pain has yet to be determined.
Further reading
- Go further — Expert guide: Is Fascia a Neurosensory Interface?
