Sciatic nerve

Sciatic nerve
Nerve: Sciatic Nerve
Latin nervus ischiadicus
Gray's subject #213 960
Innervates Lateral rotator group (except Piriformis and Quadratus femoris), Posterior compartment of thigh
From lumbar plexus and sacral plexus: L4-S3
To tibial nerve, common fibular nerve
Sciatic nerve

The sciatic nerve (also known as the ischiadic nerve and the ischiatic nerve) is a large nerve fiber in humans and other animals. It begins in the lower back and runs through the buttock and down the lower limb. It is the longest and widest single nerve in the human body.

The sciatic supplies nearly the whole of the skin of the leg, the muscles of the back of the thigh, and those of the leg and foot. It is derived from spinal nerves L4 through S3. It contains fibres from both the anterior and posterior divisions of the lumbosacral plexus.

Contents

Branches

The nerve gives off articular and muscular branches.

  • The articular branches (rami articulares) arise from the upper part of the nerve and supply the hip-joint, perforating the posterior part of its capsule; they are sometimes derived from the sacral plexus.
  • The muscular branches (rami musculares) are distributed to the following muscles of the lower limb: biceps femoris, semitendinosus, semimembranosus, and adductor magnus. The nerve to the short head of the biceps femoris comes from the common fibular part of the sciatic (see below), while the other muscular branches arise from the tibial portion, as may be seen in those cases where there is a high division of the sciatic nerve.

The muscular branch eventually gives off the tibial nerve and common fibular nerve, which innervates the muscles of the (lower) leg. The tibial nerve goes on to innervate all muscles of the foot except the extensor digitorum brevis (which is innervated by the common fibular nerve).

Tibial and common peroneal nerve

Sensory Supply

The sciatic nerve innervates the skin on the posterior aspect of the thigh and gluteal regions, as well as the entire lower leg (except for its medial aspect).

Pathology

Pain caused by a compression or irritation of the sciatic nerve by a problem in the lower back is called sciatica. Common causes of sciatica include the following low back and hip conditions: spinal disc herniation, degenerative disc disease, lumbar spinal stenosis, spondylolisthesis and piriformis syndrome.[citation needed]

Additional images

  • Structures surrounding right hip-joint.

  • Plan of sacral and pudendal plexuses.

  • Nerves of the right lower extremity Posterior view.

  • A rough schematic of the sacral plexus.

References

See also

External links

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.

v · d · eNerves of lower limbs and lower torso: the lumbosacral plexus (L1–Co) (TA A14.2.05–07, GA 9.948)
lumbar
plexus
(L1–L4)
sacral
plexus
(L4–S4)
sciatic
other
coccygeal
plexus
(S4–Co)

M: PNS

anat(h/r/t/c/b/l/s/a)/phys(r)/devp/prot/nttr/nttm/ntrp

noco/auto/cong/tumr, sysi/epon, injr

proc, drug(N1B)

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Look at other dictionaries:

  • sciatic nerve — ► NOUN Anatomy ▪ a major nerve extending from the lower end of the spinal cord down the back of the thigh …   English terms dictionary

  • Sciatic nerve — The largest nerve in the body, the sciatic nerve begins from nerve roots in the lumbar part of the spinal cord (in the low back) and extends through the buttock area to send nerve endings down to the legs. Pain resulting from irritation of the… …   Medical dictionary

  • sciatic nerve — Anat. either of a pair of nerves, the largest in the body, that originate in the sacral plexus of the lower back and extend down the buttocks to the back of the knees, where they divide into other nerves: the sciatic nerve and its branches… …   Universalium

  • sciatic nerve stretch test — a variant of the straight leg–raising test in which after the leg is raised, the ankle is dorsiflexed; if this increases pain, it indicates abnormal tension of the sciatic nerve root …   Medical dictionary

  • sciatic nerve — the major nerve of the leg and the nerve with the largest diameter. It runs down behind the thigh from the lower end of the spine; above the knee joint it divides into two main branches, the tibial and common peroneal nerves, which are… …   The new mediacal dictionary

  • sciatic nerve — noun arises from the sacral plexus and passes about halfway down the thigh where it divides into the common peroneal and tibial nerves • Syn: ↑nervus ischiadicus • Hypernyms: ↑nerve, ↑nervus • Part Holonyms: ↑leg * * * noun, pl ⋯ nerves [count] …   Useful english dictionary

  • sciatic nerve — noun Date: 1741 either of the pair of largest nerves in the body that arise one on each side from the nerve plexus supplying the posterior limb and pelvic region and that pass out of the pelvis and down the back of the thigh …   New Collegiate Dictionary

  • sciatic nerve — noun A large nerve that starts in the lower back and runs through the buttock and down the lower limb …   Wiktionary

  • sciatic nerve — n. (Anatomy) largest main nerve in the body running down from the lower end of the spinal cord to the back of the muscle of the thigh and extends through the buttock endings down at the legs …   English contemporary dictionary

  • sciatic nerve — noun Anatomy a major nerve extending from the lower end of the spinal cord down the back of the thigh …   English new terms dictionary

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