Neurodynamics · functional reading

Nerve compression

Nerve compression is the application of mechanical stress to a nerve by the tissues or structures that surround it. Depending on its intensity and duration, it can disrupt nerve circulation and conduction.

Scientific basis

A peripheral nerve runs through anatomical passages (canals, tunnels, muscular and ligamentous interfaces). Stress applied by these structures can, depending on its intensity and duration, disrupt the nerve’s microcirculation, then its conduction and, beyond that, the structure of its fibers. Entrapment syndromes are clinical examples (Rempel, Dahlin and Lundborg 1999; Topp and Boyd 2006).

The presence of compression cannot be inferred from pain, a posture or an isolated feeling of numbness. It rests on a body of clinical evidence and, depending on the case, on additional tests; for the pudendal nerve, the Nantes criteria frame this reasoning (Labat et al. 2008).

The sheaths of the nerve. A peripheral nerve is organized in connective tissue layers: the endoneurium surrounds each fiber, the perineurium each fascicle, and the epineurium the whole nerve. Around the epineurium, a loose connective tissue (the paraneurium) links it to neighboring structures and allows it to glide (Millesi and Zöch 1990; Topp and Boyd 2006). These sheaths are themselves innervated (Bove 2008). Proximity between a nerve and a fascia implies neither mechanical stress nor nerve damage.

Blue Portance / SBNFA™ reading

In the SBNFA™ framework, nerve compression is one possible mechanical interaction between a nerve and its environment. The framework considers it among other hypotheses in some types of pain that worsen when sitting, without presuming it.

Contribution to the analysis of sitting

Seating analysis does not detect nerve compression. It describes pelvic orientation and the distribution of support, which change the mechanical conditions around certain nerve pathways; interpreting them is a matter for medical evaluation.

Not to be confused with

Neuropathic pain, which implies a lesion or disease of the somatosensory nervous system; Neuralgia, pain in the territory of a nerve; “Pinched nerve” and “trapped nerve,” everyday expressions, not diagnoses; Neural tension, the tensioning of a nerve as its pathway lengthens; Peripheral sensitization and central sensitization, processes that change how the nervous system responds; Nerve irritation and reduced functional space, covered in this entry.

Sources and scope

Established pathophysiological concept. Sitting does not necessarily compress the pudendal nerve, pain when sitting does not prove nerve compression, and no seat “frees a pinched nerve.”