Clinical term

Sciatica

Sciatica is pain that follows the path of the sciatic nerve, from the buttock down the back or side of the leg, sometimes as far as the foot. It is most often related to irritation of a lower lumbar nerve root (L5 or S1), frequently from a herniated disc.

Scientific basis

The sciatic nerve is formed by the joining of lumbar and sacral roots (L4 to S3). When an L5 or S1 root is irritated or compressed, pain radiates into its territory: the outer side of the leg, the top of the foot and the big toe for L5; the back of the leg, the heel, the sole and the outer edge of the foot for S1.

The pain may be accompanied by tingling, reduced sensation and, more rarely, loss of strength. The most common causes are disc herniation and, in older people, osteoarthritis or narrowing of the lumbar spinal canal. The outcome is often favorable within a few weeks.

Blue Portance / SBNFA™ reading

The SBNFA™ distinguishes the neurological mechanism of pain from the mechanical conditions of the nerve’s environment: relative mobility, gliding, sustained positions, duration of exposure and variability of configurations.

Nerves move relative to the surrounding tissues during movements of the trunk and limbs. The SBNFA™ reading therefore looks at what the situation leaves possible for this adjustment, as a complement to diagnosing the cause.

Contribution to the analysis of sitting

Some people with sciatica tolerate prolonged sitting poorly. Observing pelvic orientation, hip position and the possibility of shifting support provides functional information, but cannot on its own determine the origin of the pain.

Not to be confused with

Femoral neuralgia, which affects the front of the thigh (L3-L4 roots); piriformis syndrome, sometimes called “false sciatica”; pudendal neuralgia, perineal pain; buttock pain of sacroiliac origin or referred from the lumbar spine, which does not follow the path of a nerve root.

Sources and scope

Established clinical definitions. In case of loss of strength, urinary problems or numbness of the perineum, seek urgent medical care.