Sciatic nerve

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Sciatic nerve
Sciatic nerve2.jpg
Right gluteal region, showing surface markings for arteries and sciatic nerve
Details
Pronunciation /sˈætɪk/
From Lumbar and sacral plexus (L4-S3)
To Tibial and common fibular nerve
Innervates Lateral rotator group (except piriformis and quadratus femoris) and the posterior compartment of thigh
Identifiers
Latin nervus ischiadicus
MeSH D012584
TA98 A14.2.07.046
TA2 6569
FMA 19034
Anatomical terms of neuroanatomy

The sciatic nerve, also called the ischiadic nerve, is a large nerve in humans and other vertebrate animals. It is the largest branch of the sacral plexus and runs alongside the hip joint and down the lower limb. It is the longest and widest single nerve in the human body, going from the top of the leg to the foot on the posterior aspect. The sciatic nerve has no cutaneous branches for the thigh. This nerve provides the connection to the nervous system for the skin of the lateral leg and the whole foot, the muscles of the back of the thigh, and those of the leg and foot. It is derived from spinal nerves L4 to S3. It contains fibres from both the anterior and posterior divisions of the lumbosacral plexus.

Contents

Structure

In humans, the sciatic nerve is formed from the L4 to S3 segments of the sacral plexus, a collection of nerve fibres that emerge from the sacral part of the spinal cord. The lumbosacral trunk from the L4 and L5 roots descends between the sacral promontory and ala, and the S1 to S3 roots emerge from the ventral sacral foramina. These nerve roots unite to form a single nerve in front of the piriformis muscle. The nerve passes beneath the piriformis and through the greater sciatic foramen, exiting the pelvis. [1] :422–4 From here, it travels down the posterior thigh to the popliteal fossa. The nerve travels in the posterior compartment of the thigh behind (superficial to) the adductor magnus muscle and is itself in front of (deep to) the long head of the biceps femoris muscle. At the popliteal fossa, the nerve divides into its two branches: [1] :532

The sciatic nerve is the largest nerve in the human body. [2] :422–4 [3] [4]

3D still showing Sciatica. 3D still showing Sciatica nerve.jpg
3D still showing Sciatica.
Tibial and common fibular nerve (aka common peroneal nerve) Tibial nerve and common peroneal nerve.jpg
Tibial and common fibular nerve (aka common peroneal nerve)

Development

Function

The sciatic nerve supplies sensation to the skin of the foot, as well as the entire lower leg (except for its inner side). Sensation to skin to the sole of the foot is provided by the tibial nerve, and the lower leg and upper surface of the foot via the common fibular nerve. [2] :422–4

The sciatic nerve also innervates muscles. In particular: [2] :422–4

Clinical significance

Sciatica

Pain caused by compression or irritation of the sciatic nerve by a problem in the lower back is called sciatica. Common causes of sciatica include the following lower back and hip conditions: spinal disc herniation, degenerative disc disease, lumbar spinal stenosis, spondylolisthesis, and piriformis syndrome. [5] Other acute causes of sciatica include coughing, muscular hypertension, and sneezing. [6]

Injury

A sciatic nerve injury occurs between 0.5% and 2.0% of the time during a hip replacement. [7] Sciatic nerve palsy is a complication of total hip arthroplasty with an incidence of 0.2% to 2.8% of the time, or with an incidence of 1.7% to 7.6% following revision. [8] Following the procedure, in rare cases, a screw, broken piece of trochanteric wire, fragment of methyl methacrylate bone cement, or Burch-Schneider antiprofusio cage can impinge on the nerve; this can cause sciatic nerve palsy, which may resolve after the fragment is removed and the nerve is freed. The nerve can be surrounded by oxidised, regenerated cellulose to prevent further scarring. Sciatic nerve palsy can also result from severe spinal stenosis following the procedure, which can be addressed by spinal decompression surgery. [7] [9] It is unclear if inversion therapy is able to decompress the sacral vertebrae; it may only work on the lumbar aspects of the sciatic nerves.

A sciatic nerve injury may also occur from improperly performed injections into the buttock, and may result in sensory loss. [10] :66

Other disease

Bernese periacetabular osteotomy resulted in major nerve deficits in the sciatic or femoral nerves in 2.1% of 1760 patients, of whom approximately half experienced complete recovery within a mean of 5.5 months. [11]

Sciatic nerve exploration can be done by endoscopy in a minimally invasive procedure to assess lesions of the nerve. [12] Endoscopic treatment for sciatic nerve entrapment has been investigated in deep gluteal syndrome. Patients were treated with sciatic nerve decompression by resection of fibrovascular scar bands, piriformis tendon release, obturator internus, or quadratus femoris, or by hamstring tendon scarring. [13]

Anaesthetic

Signals from the sciatic nerve and its branches can be blocked, in order to interrupt the transmission of pain signals from the innervation area, by performing a regional nerve blockade called a sciatic nerve block.

Society and culture

According to Jewish law, the sciatic nerve (Hebrew: Gid hanasheh) may not be eaten by Jews to commemorate Jacob's injury in his struggle with an angel. [14]

Additional images

See also

Notes

  1. Namely the flexor hallicus longus, flexor digitorum longus, tibialis posterior and popliteus of the deep part of the compartment, and the gastrocnemius, soleus and plantaris of the superficial part of the compartment.
  2. Namely the tibialis anterior, extensor hallucis longus, extensor digitorum longus, and fibularis tertius (peroneus tertius) of the anterior compartment, and the Fibularis longus and brevis of the lateral compartment.

Related Research Articles

<span class="mw-page-title-main">Human leg</span> Lower extremity or limb of the human body (foot, lower leg, thigh and hip)

The leg is the entire lower limb of the human body, including the foot, thigh or sometimes even the hip or buttock region. The major bones of the leg are the femur, tibia, and adjacent fibula. The thigh is between the hip and knee, while the calf (rear) and shin (front) are between the knee and foot.

<span class="mw-page-title-main">Spinal nerve</span> Nerve that carries signals between the spinal cord and the body

A spinal nerve is a mixed nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body. In the human body there are 31 pairs of spinal nerves, one on each side of the vertebral column. These are grouped into the corresponding cervical, thoracic, lumbar, sacral and coccygeal regions of the spine. There are eight pairs of cervical nerves, twelve pairs of thoracic nerves, five pairs of lumbar nerves, five pairs of sacral nerves, and one pair of coccygeal nerves. The spinal nerves are part of the peripheral nervous system.

<span class="mw-page-title-main">Sciatica</span> Lower back pain that extends down leg

Sciatica is pain going down the leg from the lower back. This pain may go down the back, outside, or front of the leg. Onset is often sudden following activities like heavy lifting, though gradual onset may also occur. The pain is often described as shooting. Typically, symptoms are only on one side of the body. Certain causes, however, may result in pain on both sides. Lower back pain is sometimes present. Weakness or numbness may occur in various parts of the affected leg and foot.

<span class="mw-page-title-main">Piriformis muscle</span> Hip muscle in the lateral rotator group

The piriformis muscle is a flat, pyramidally-shaped muscle in the gluteal region of the lower limbs. It is one of the six muscles in the lateral rotator group.

<span class="mw-page-title-main">Piriformis syndrome</span> Medical condition

Piriformis syndrome is a condition which is believed to result from nerve compression at the sciatic nerve by the piriformis muscle. It is a specific case of deep gluteal syndrome. The largest and most bulky nerve in the human body is the sciatic nerve. Starting at its origin it is 2 cm wide and 0.5 cm thick. The sciatic nerve forms the roots of L4-S3 segments of the lumbosacral plexus. The nerve will pass inferiorly to the piriformis muscle, in the direction of the lower limb where it divides into common tibial and fibular nerves. Symptoms may include pain and numbness in the buttocks and down the leg. Often symptoms are worsened with sitting or running.

<span class="mw-page-title-main">Gastrocnemius muscle</span> Calf muscle

The gastrocnemius muscle is a superficial two-headed muscle that is in the back part of the lower leg of humans. It is located superficial to the soleus in the posterior (back) compartment of the leg. It runs from its two heads just above the knee to the heel, extending across a total of three joints.

The biceps femoris is a muscle of the thigh located to the posterior, or back. As its name implies, it consists of two heads; the long head is considered part of the hamstring muscle group, while the short head is sometimes excluded from this characterization, as it only causes knee flexion and is activated by a separate nerve.

<span class="mw-page-title-main">Plantaris muscle</span> One of the superficial muscles of the superficial posterior compartment of the leg

The plantaris is one of the superficial muscles of the superficial posterior compartment of the leg, one of the fascial compartments of the leg.

<span class="mw-page-title-main">Nerve plexus</span> Network of nerve fibres

A nerve plexus is a plexus of intersecting nerves. A nerve plexus is composed of afferent and efferent fibers that arise from the merging of the anterior rami of spinal nerves and blood vessels. There are five spinal nerve plexuses, except in the thoracic region, as well as other forms of autonomic plexuses, many of which are a part of the enteric nervous system. The nerves that arise from the plexuses have both sensory and motor functions. These functions include muscle contraction, the maintenance of body coordination and control, and the reaction to sensations such as heat, cold, pain, and pressure. There are several plexuses in the body, including:

<span class="mw-page-title-main">Sacral plexus</span> Nerve plexus

In human anatomy, the sacral plexus is a nerve plexus which provides motor and sensory nerves for the posterior thigh, most of the lower leg and foot, and part of the pelvis. It is part of the lumbosacral plexus and emerges from the lumbar vertebrae and sacral vertebrae (L4-S4). A sacral plexopathy is a disorder affecting the nerves of the sacral plexus, usually caused by trauma, nerve compression, vascular disease, or infection. Symptoms may include pain, loss of motor control, and sensory deficits.

<span class="mw-page-title-main">Posterior cutaneous nerve of thigh</span> Sensory nerve that supplies the back of the thigh, leg, buttock, and perineum

The posterior cutaneous nerve of the thigh is a sensory nerve of the thigh. It is a branch of the sacral plexus. It supplies the skin of the posterior surface of the thigh, leg, buttock, and also the perineum.

<span class="mw-page-title-main">Inferior gluteal nerve</span>

The inferior gluteal nerve is the main motor neuron that innervates the gluteus maximus muscle. It is responsible for the movement of the gluteus maximus in activities requiring the hip to extend the thigh, such as climbing stairs. Injury to this nerve is rare but often occurs as a complication of posterior approach to the hip during hip replacement. When damaged, one would develop gluteus maximus lurch, which is a gait abnormality which causes the individual to 'lurch' backwards to compensate lack in hip extension.

<span class="mw-page-title-main">Inferior gluteal artery</span>

The inferior gluteal artery is a terminal branch of the anterior trunk of the internal iliac artery. It exits the pelvis through the greater sciatic foramen. It is distributed chiefly to the buttock and the back of the thigh.

<span class="mw-page-title-main">Nerve to obturator internus</span> Human nerve

The nerve to obturator internus is a mixed nerve providing motor innervation to the obturator internus muscle and gemellus superior muscle, and sensory innervation to the hip joint. It is a branch of the sacral plexus. It is one of the group of deep gluteal nerves.

<span class="mw-page-title-main">Posterior compartment of thigh</span> One of the fascial compartments that contains the knee flexors and hip extensors

The posterior compartment of the thigh is one of the fascial compartments that contains the knee flexors and hip extensors known as the hamstring muscles, as well as vascular and nervous elements, particularly the sciatic nerve.

<span class="mw-page-title-main">Outline of human anatomy</span> Overview of and topical guide to human anatomy

The following outline is provided as an overview of and topical guide to human anatomy:

<span class="mw-page-title-main">Outline of the human nervous system</span> Overview of and topical guide to the human nervous system

The following diagram is provided as an overview of and topical guide to the human nervous system:

<span class="mw-page-title-main">Deep gluteal syndrome</span> Medical condition

Deep gluteal syndrome describes the non-discogenic extrapelvic entrapment of the sciatic nerve in the deep gluteal space. In simpler terms this is sciatica due to nerve irritation in the buttocks rather than the spine or pelvis. It is an extension of non-discogenic sciatic nerve entrapment beyond the traditional model of piriformis syndrome. Where sciatic nerve irritation in the buttocks was once thought of as only piriformis muscle, it is now recognized that there are many other causes. Symptoms are pain or dysthesias in the buttocks, hip, and posterior thigh with or without radiating leg pain. Patients often report pain when sitting. The two most common causes are piriformis syndrome and fibrovascular bands, but many other causes exist. Diagnosis is usually done through physical examination, magnetic resonance imaging, magnetic resonance neurography, and diagnostic nerve blocks. Surgical treatment is an endoscopic sciatic nerve decompression where tissue around the sciatic nerve is removed to relieve pressure.

References

PD-icon.svgThis article incorporates text in the public domain from page 960 of the 20th edition of Gray's Anatomy (1918)

  1. 1 2 Drake, Richard L.; Vogl, Wayne; Tibbitts, Adam W.M. Mitchell; illustrations by Richard; Richardson, Paul (2005). Gray's anatomy for students. Philadelphia: Elsevier/Churchill Livingstone. ISBN   978-0-8089-2306-0.
  2. 1 2 3 Drake, Richard L.; Vogl, Wayne; Tibbitts, Adam W.M. Mitchell; illustrations by Richard; Richardson, Paul (2005). Gray's anatomy for students. Philadelphia: Elsevier/Churchill Livingstone. ISBN   978-0-8089-2306-0.
  3. "What Is Sciatica?". WebMD. Medically Reviewed by Tyler Wheeler. Retrieved 12 May 2022.{{cite web}}: CS1 maint: others (link)
  4. Winn, Richard; Youmans, Julian (2017). Youmans & Winn neurological surgery. Elsevier. ISBN   9780323287821.
  5. "Sciatica - Topic Overview". WebMD. 21 July 2010. Retrieved 23 April 2012.
  6. "What is sciatica: What causes sciatica?". MedicalBug. 11 April 2012. Retrieved 23 April 2012.
  7. 1 2 Stiehl JB, Stewart WA (1998). "Late sciatic nerve entrapment following pelvic plate reconstruction in total hip arthroplasty". J Arthroplasty. 13 (5): 586–8. doi:10.1016/s0883-5403(98)90060-2. PMID   9726326.
  8. Alessandro Bistolfi; et al. (2011). "Operative Management of Sciatic Nerve Palsy due to Impingement on the Metal Cage after Total Hip Revision: Case Report". Case Rep Med. 2011: 1–3. doi: 10.1155/2011/830296 . PMC   3163138 . PMID   21876701.
  9. Abitbol JJ, Gendron D, Laurin CA, Beaulieu MA (1990). "Gluteal nerve damage following total hip arthroplasty. A prospective analysis". J Arthroplasty. 5 (4): 319–22. doi:10.1016/s0883-5403(08)80090-3. PMID   2290087.is cited by Stiehl and Stewart for the 0.5-2.0% figure.
  10. James, William D.; Berger, Timothy G.; et al. (2006). Andrews' Diseases of the Skin: clinical Dermatology. Saunders Elsevier. ISBN   978-0-7216-2921-6.
  11. Sierra RJ, Beaule P, Zaltz I, Millis MB, Clohisy JC, Trousdale RT (2012). "Prevention of nerve injury after periacetabular osteotomy". Clin. Orthop. Relat. Res. 470 (8): 2209–19. doi:10.1007/s11999-012-2409-1. PMC   3392380 . PMID   22684336.
  12. Mobbs RJ, Teo C (2004). "Endoscopic-assisted sciatic nerve exploration". Minim Invasive Neurosurg. 47 (3): 178–80. doi:10.1055/s-2004-818488. PMID   15343436. S2CID   260241055.
  13. Martin HD, Shears SA, Johnson JC, Smathers AM, Palmer IJ (2011). "The endoscopic treatment of sciatic nerve entrapment/deep gluteal syndrome". Arthroscopy. 27 (2): 172–81. doi: 10.1016/j.arthro.2010.07.008 . PMID   21071168.
  14. Goldberger, Moshe. "1: Not to Eat the Gid HaNasheh". The First Prohibitions. Retrieved 10 March 2014.