Clinical term

Herniated disc

A herniated disc is the localized displacement of part of the intervertebral disc, most often the nucleus, through a tear in the annulus fibrosus. It can irritate or compress a nerve root, but it is also frequently painless.

Scientific basis

The disc consists of a gelatinous central core (nucleus pulposus) surrounded by a fibrous ring (annulus fibrosus). When the ring tears, part of the nucleus can extend beyond it in a localized way, unlike a protrusion, which corresponds to a more diffuse bulge.

In the lumbar spine, herniations mainly affect the L4-L5 and L5-S1 levels. They can cause lumbar radicular pain: sciatica or, more rarely, femoral neuralgia.

Disc abnormalities are common in people without pain. Disc protrusions in particular are observed in a large proportion of asymptomatic individuals, and their presence on imaging is not enough to explain pain. Many disc herniations regress spontaneously over time.

Blue Portance / SBNFA™ reading

The SBNFA™ distinguishes between the abnormality visible on imaging and the way the system organizes itself around it. The same herniation can be silent in one person and painful in another, depending in particular on nerve root irritation, local inflammation, the sensitivity of the nervous system and mechanical compensations.

It is this organization around the lesion — and the possibilities for adjustment that remain available — that the SBNFA™ adds to the reading of the image.

Contribution to the analysis of sitting

In a person with a herniated disc, prolonged sitting may be tolerated more or less well. Observing how long a position is held, the orientation of the pelvis and the possibilities for varying the points of support can shed light on this tolerance, without replacing a medical diagnosis.

Not to be confused with

Disc protrusion, an overall, diffuse bulge; intervertebral disc disease, a more general alteration of the disc; sciatica and femoral neuralgia, which refer to pain, not to lesions.

Sources and scope

Established anatomy and imaging data. In the presence of neurological signs (loss of strength, bladder or bowel dysfunction, saddle anesthesia), urgent medical attention is required.