Nerf sciatique

Nervus ischiadicus

The largest and longest nerve in the body, the sciatic nerve supplies motor innervation to the posterior thigh and every muscle below the knee, and sensation to the lateral leg, the foot, and part of the posterior thigh. Arising from the L4 to S3 roots of the sacral plexus, it leaves the pelvis through the greater sciatic foramen below the piriformis muscle, descends through the posterior thigh, and usually divides into the tibial and common peroneal nerves at the popliteal fossa. Irritation of the nerve, often from a herniated disc, produces sciatica, a pain that radiates down the back of the leg. Piriformis syndrome compresses it in the buttock, misplaced gluteal injections can injure it, and a complete lesion abolishes all movement below the knee.

Il se forme à partir des racines nerveuses L4-S3 du plexus sacré. Il quitte le bassin par le foramen ischiatique majeur, sous le muscle piriforme. Il descend dans la cuisse postérieure, se divisant en nerfs tibial et fibulaire commun, généralement au niveau de la fosse poplitée.

On this page
Type Nerve
Système corporel Nerveux
Région corporelle Hanche
Structure parente nerve
Nom latin Nervus ischiadicus
FMA ID 19034

Fonction

Le nerf le plus long et le plus épais du corps, assurant l'innervation motrice de la cuisse postérieure et de tous les muscles sous le genou. Il assure l'innervation sensitive de la face latérale de la jambe, du pied et de certaines parties de la cuisse postérieure.

Signification clinique

La sciatique (irritation du nerf sciatique, souvent due à une hernie discale) provoque une douleur irradiant le long de la face postérieure de la jambe. Le syndrome du piriforme comprime le nerf au niveau de la fesse. Des injections glutéales mal réalisées peuvent endommager le nerf. Une lésion complète du nerf sciatique provoque la perte de tout mouvement sous le genou.

Frequently Asked Questions

What does the sciatic nerve do?

The sciatic nerve is the largest and longest nerve in the human body. It provides motor innervation to most muscles of the posterior thigh and all muscles of the lower leg and foot. It also carries sensory information from the skin of the lower leg, foot, and part of the thigh back to the spinal cord.

Where is the sciatic nerve located?

The sciatic nerve forms from nerve roots L4 through S3 in the sacral plexus. It exits the pelvis through the greater sciatic foramen, typically below the piriformis muscle, and runs deep in the posterior thigh between the hamstring muscles. At the popliteal fossa behind the knee, it divides into the tibial nerve and common fibular nerve.

What causes sciatica?

Sciatica refers to pain radiating along the path of the sciatic nerve, typically from the lower back through the buttock and down the leg. The most common cause is a herniated lumbar disc compressing a nerve root (most often L4, L5, or S1). Other causes include spinal stenosis, piriformis syndrome, and rarely, tumors or injuries along the nerve's course.

References

  1. Foundational Model of Anatomy — FMA:19034 Reference anatomy ontology (University of Washington)
  2. UBERON — UBERON:0001322 Cross-species anatomy ontology (EMBL-EBI Ontology Lookup Service)
  3. Wikidata — Q307869 Structured knowledge base cross-reference
  4. Wikipedia — Nerf sciatique Encyclopedia article (verified cross-reference)

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Educational Disclaimer

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Data sources: Terminologia Anatomica, Foundational Model of Anatomy, Wikidata.