Clinical term

Low back pain

Low back pain is pain in the lower back, located between the thoracolumbar junction and the gluteal fold. In the vast majority of cases it is described as common (non-specific): it is mechanical in origin and does not stem from a serious disease.

Scientific basis

A classic distinction is made between acute low back pain, lasting less than 6 weeks; subacute low back pain, lasting between 6 weeks and 3 months; and chronic low back pain, lasting beyond 3 months.

Low back pain is now the leading cause of disability worldwide. For most people affected, it is not possible to identify a specific nociceptive source: muscles, ligaments, joints and discs can all contribute to the pain, often in combination.

The French National Authority for Health (HAS) distinguishes common low back pain, by far the most frequent form, from so-called symptomatic low back pain, which is linked to a specific cause (infection, inflammation, tumor, fracture). The latter is rare; the medical history and physical examination look for it on the basis of warning signs known as "red flags." When the pain radiates into the lower limb along the path of a nerve, it is called lumbar radicular pain (sciatica or femoral neuralgia).

Blue Portance / SBNFA™ reading

SBNFA™ does not seek to single out one structure as responsible. It complements the question "which structure is affected?" with other questions: how are loads distributed? which movements remain available? can the pelvis and hips change configuration? are some regions compensating for others over the long term?

This reading does not replace diagnosis: it shifts the scale of analysis from the isolated structure to the functional capacities of the system, that is, to its adaptive potential.

Contribution to the analysis of sitting

Sitting changes the orientation of the pelvis and the organization of the lumbar spine. When low back pain appears or increases while sitting, observing how long the position is held, the variability of support and the relationship between the pelvis and the femurs provides functional information, without on its own identifying the origin of the pain.

Not to be confused with

Lumbar radicular pain (sciatica, femoral neuralgia), where the pain follows the path of a nerve root; lumbago, a common term for an acute episode; MSDs, a broader occupational health category.

Sources and scope

Established definitions and classification (HAS, international literature). This entry does not replace a medical evaluation, particularly when warning signs are present.