Anatomy · functional reading
Thoracolumbar fascia
The thoracolumbar fascia is a set of connective tissue layers in the lower back. It envelops the deep back muscles and receives the attachments or extensions of several muscles of the trunk and pelvis.
Scientific basis
In particular, it receives attachments from the latissimus dorsi, gluteus maximus, transversus abdominis and the abdominal obliques. Depending on the description, it has two or three layers; it contributes to load transfer between the trunk, the pelvis and the limbs (Willard et al., 2012).
It is innervated mainly by free nerve endings, more numerous in the superficial layers, some of which are nociceptive (Tesarz et al., 2011). In volunteers, an injection of hypertonic saline into this fascia causes more intense and longer-lasting pain than in the underlying muscle (Schilder et al., 2014).
In chronic low back pain, an observational study measured about 20% less shear motion (Langevin et al., 2011). Its stiffness also varies with knee position and with contraction of the thigh muscles (Kellis et al., 2024).
Blue Portance / SBNFA™ reading
SBNFA™ reads the thoracolumbar fascia as a crossroads between the pelvis and the trunk: it is both a pathway for load distribution and a sensory interface. The hypothesis that a fixed sitting position deprives this crossroads of the variability that maintains its gliding is part of the SBNFA™ reading.
Contribution to the analysis of sitting
In a seated position, pelvic orientation changes the tension of the lumbar structures. The analysis observes whether the pelvis can still tilt and shift its support, without attributing low back pain to this fascia.
Not to be confused with
Lumbar aponeurosis, an older term for part of this structure; erector spinae muscles, which it envelops; fascia, the family of tissues of which it is one example.
Related terms
Sources and scope
- Willard et al. (2012): the thoracolumbar fascia, anatomy, function and clinical considerations (Journal of Anatomy)
- 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)
- Langevin et al. (2011): reduced thoracolumbar fascia shear strain in chronic low back pain (BMC Musculoskelet Disord)
Anatomy and innervation are established; its contribution to a given case of low back pain cannot be asserted from a single examination.
Further reading
- Learn more — Article: Back Pain and Biotensegrity: What If Your Spine Isn’t a Stack of Vertebrae?
- Go further — Expert guide: Is Fascia a Neurosensory Interface?
