From Big Medical Encyclopedia

SCIATIC NERVE [nervus ischiadicus (PNA, JNA, BNA)] — the mixed nerve originating from a sacriplex and participating in an innervation of the lower extremity.

The page of N is a long branch of a sacriplex (see. Lumbosacral texture ), contains the nerve fibrils departing from segments of a spinal cord L4 — S3. S. of N in small forms to a basin (see) near big sciatic opening (foramen ischiadicum ma-jus) also leaves a pelvic cavity through subpiriform opening (foramen infrapiriforme) together with the artery accompanying a sciatic nerve (a. comitans n. ischiadici). In subpiriform opening the nerve is located more lateralno; higher and knutr from it go the lower buttock artery (a. glutea inf.) with the veins accompanying it and the lower buttock nerve (n. gluteus inf.). Medially there passes the back cutaneous nerve of a hip (n. cutaneus femoris post.), and also the neurovascular bunch consisting of an internal sexual artery (a. pudenda int.), veins and sexual nerve (n. pudendus). The page of N can leave through a nadgrushevidny opening (foramen suprapiriforme) or directly through thickness grushevidnokh! muscles (m. piriformis), and in the presence of two trunks — through both openings.

In rump (see) S. the N is located under a big gluteus (m. gluteus maximus) behind twin muscles (vol. of gemelli), an internal locking muscle (m. obturatorius int.) and square muscle of a hip (m. quadratus femoris). In this place branches depart from S. of N to to a hip joint (see).

In the field of a buttock fold of S. of N lies superficially under a wide fascia of a hip of a knaruzha from a long head of a biceps of a hip (m. biceps femoris). Further it goes down the centerline of a back surface hips (see), between a biceps of a hip, semitendinous (m. semitendinosus) and semimembranous (m. semimembranosus) muscles, kzad from a big adductor (m. adductor magnus).

Fig. 1. The diagrammatic representation of back area of the right hip, coxofemoral and knee joints at low division of a sciatic nerve in a popliteal space (a) and at high division of a sciatic nerve (b) with an exit of a fibular nerve through a nadgrushevidny opening, a tibial nerve — through subpiriform opening (skin, hypodermic cellulose and partially muscles of back area of a hip are removed): 1 — a tibial nerve; 2 — the general fibular nerve; 3 — a sciatic nerve.

Around a nerve on all its extent the vascular network is formed of a numerous anastomosis (an artery companion, branches of the lower buttock and subnodal arteries), to-rye carry out S.'s blood supply N. On a hip muscular branches depart from S. of N (rr. musculares) to a biceps of a hip, semitendinous and semimembranous muscles, and also to a big adductor. As a rule, in an upper part of a popliteal space the nerve is divided into final branches (fig. 1, a): tibial nerve (n. tibialis) and general fibular nerve [n. peroneus (fibularis communis)]. However division of a nerve can happen at the different levels. Can be one of options of norm separate from - circulation tibial and the general fibular nerves directly from a sacriplex (fig. 1, b).

The tibial nerve at an independent otkhozhdeniye from a sacriplex is formed of L4 segments — L5, S1 — S2. The nerve on character of fibers mixed, passes through nadgrushevidny or subpiriform opening, its topography on a hip is similar to S.'s course of N. Then it passes in the middle of a popliteal space, being located lateralny and poverkhnostny subnodal Bena and an artery, and together with vessels goes to golenopodkolenny channel (canalis cruropopliteus) through its upper opening. The tibial nerve passes in the channel with a back tibial artery and a vein between deep and superficial sgibatel to the lower opening of the channel, then is located behind a medial anklebone under a retinaculum of sinews-sgibateley (retinaculum musculorum flexorum) where is divided into two final branches — medial and lateral bottom nerves (nn. plantaris med. et lat.).

The tibial nerve innervates back group of muscles of a shin, all muscles of a sole, skin of the back side of a shin, skin of a heel and lateral edge of foot and the V finger, skin of a sole and bottom side of all five fingers, sends branches to knee and talocrural joints.

It is divided into several branches.

1. Muscular branches (rr. musculares), the shins going to back group of muscles. 2. The branches going to a knee joint. 3. Medial cutaneous nerve of caviar (n. cutaneus surae med.), going together with a small saphena under a fascia of a shin in a groove between paunches of a gastrocnemius muscle. In the lower third of a shin the nerve probodat a fascia, becomes a hypodermic nerve and, connecting to a skin branch of a fibular nerve, forms a sural nerve (n. suralis), to-ry behind lateral anklebone is divided into lateral calcaneal branches (rr. calcanei laterales), and further forms a lateral back cutaneous nerve (n. cutaneus dorsalis lat.), reaching the basis of a trailer phalanx of the V finger. 4. The branches going to an ankle joint. 5. Medial calcaneal branches (rr. calcanei med.). 6. Medial and lateral bottom nerves. The medial bottom nerve innervates group of muscles of the I finger — a short sgibatel of fingers, the muscle which is taking away the I finger of foot, a head of a short sgibatel of the I finger and worm-shaped muscles of I and II fingers gives skin branches to medial edge of foot and the I finger. The medial bottom nerve is divided into three general manual bottom nerves (nn. digitales plantares communes), to-rye, passing between a bottom aponeurosis and a short sgibatel of fingers (m. flexor digitorum brevis), are divided everyone into two own manual bottom nerves (nn. digitales plantares proprii), the innervating skin of the sides of the I—IV fingers turned to each other. The lateral bottom nerve accompanies the artery of the same name and is divided into deep and superficial branches (rr. profundus et superficialis). The superficial branch is divided into bottom and manual nerves (subitem of digitales plantares) going to lateral side of the V finger and to the parties turned to each other V and IV fingers. The deep branch of a lateral bottom nerve innervates a square muscle of a sole (m. quadratus plantae), group of muscles of the V finger, worm-shaped muscles of the III—IV fingers, interosseous muscles, the muscle giving the I finger and a lateral head of a short sgibatel of the I finger of foot.

The general fibular nerve [n. peroneus (fibularis) communis] is formed of L4 segments — L5 and S1 — S5 and is mixed on structure of branches. Having separated from S. N, it goes along the lateral party of a popliteal space, bending around a head of a fibular bone, and is divided into final branches — deep fibular and superficial fibular nerves. The general fibular nerve gives branches: the branch going to a knee joint and a lateral cutaneous nerve of caviar (n. cutaneus surae lat.). The last falls under a fascia of a shin on a back surface of a lateral head of a gastrocnemius muscle and sends a fibular connecting branch to a medial cutaneous nerve of caviar, innervates skin of a lateral surface of a shin.

The deep fibular nerve [n. peroneus (fibularis) profundus] accompanies lobbies a tibial artery and a vein and innervates front muscles of a shin, back muscles of foot and skin of the back of fingers of foot in the area I of an interdigital interval.

The superficial fibular nerve [n. peroneus (fibularis) superficialis] passes in the upper muscular and fibular channel, innervates long and short fibular muscles, skin of the back of fingers of foot, except for the I interdigital interval. Its branches medial back skin and intermediate back skin nerves (nn. cutanei dorsales medialis et intermedius) come to an end in the form of back manual nerves of foot (nn. digitales dorsales pedis).


the Reasons of defeat of S. of N are various — infections, intoxications, local cooling, injuries, diseases of bodies of a small pelvis, dystrophic and other changes of a backbone (the osteochondrosis deforming a spondylarthrosis, a spondylolisthesis, loss of an intervertebral disk), and also anomalies of its development in a look sacralization (see), lumbalizations (see) and splittings of handles of sacral vertebrae (see. Spina bifida ).

Damages Pages of N result from bruises and stretchings, at fractures and dislocations, at a prelum aneurism, a tumor as a complication at surgeries. Allocate injection damages of S. of N to a rump, to genesis to-rykh the injury a needle, excessively bystry introduction and toxicity of the entered medicine matters. Gunshot wounds of S. of N in wartime borrowed, but to B. S. Doynikov (1935) data, N. I. Mironovich (1952), one of the first places among wounds of nerves. In peace time tibial and fibular nerves in subnodal area and on a shin are more often injured.

Fig. 2. The diagrammatic representation of zones of the broken sensitivity on skin of a shin and foot at a break of a sciatic nerve (in black color the zone of anesthesia, by points — a zone of a hypesthesia is shown): and — an anterior aspect; — the back view.

At a full break of S. of N in a rump and in upper parts of a hip from the moment of damage the active movements of foot and fingers are lost. Sensitivity is broken to degree of anesthesia on a sole and a heel, on the back of foot and on an anteroexternal surface of the lower third of a shin. On the periphery of sites of anesthesia the narrow zone of a hypesthesia (fig. 2) comes to light. Bending in a knee joint usually is not broken since the main branches, the innervating muscles of a back surface of a hip, depart above, sometimes directly from a sacriplex. At a full break of N walking is complicated by S., but is possible; at a break only of a fibular nerve it is very complicated because of droop of foot. At injury only of a tibial nerve on a hip of stop resides in the provision of extension («calcaneal foot»), the patient cannot get up on socks. At a break of a fibular nerve there comes paralysis of front and outside groups of muscles of a shin owing to what the patient cannot unbend foot and raise its outer edge.

For diagnosis of injury of a tibial nerve if the wound is located above a knee joint, it is necessary otsenlt a condition of back group of muscles of a shin, having suggested the patient to bend foot and to investigate sensitivity of skin on a sole. If the wound is located at the level of a knee joint or below it i.e. where branches to back group of muscles of a shin already separated, bending of foot is not broken; in this case investigate a possibility of bending of fingers and sensitivity of a sole. Denervation of a sole and a heel at a break of a tibial nerve at any level constitutes the main danger because the bottom surface during the walking is injured and the hardly healing ulcers are formed. Also plusnevy bones are involved in dystrophic process calcaneal over time. It is long not healing ulcer and damage of bones of foot can be a reason for amputation of a shin, sometimes years later after damage. The complete recovery of sensitivity on a sole comes seldom; it is long the phenomena of a hyperpathia and paresthesia remain. Quite often contractures of foot and fingers in the wrong situation develop.

Fig. 3. The diagrammatic representation of quick access to a sciatic nerve in a rump by means of a section across Radziyevsky: 1 — a sciatic nerve; 2 — a back cutaneous nerve of a hip; 3 — a sexual nerve; 4 — the big gluteus (is dissect and turned away); 5 — a pear-shaped muscle; 6 — an average gluteus; 7 — the lower buttock artery (is crossed).
Fig. 4. The diagrammatic representation of quick access to a sciatic nerve in back area of the left hip: 1 — a biceps of a hip (an upper part is removed by hooks of a knutra, lower — knaruzh); 2 — the semitendinous muscle (is delayed); 3 — a semimembranous muscle; 4 — a sciatic nerve.

At open damages with the full disturbance of conductivity confirmed with data of electrodiagnosis and an electromyography stitching on S. is shown to N (see. Nervous seam). For a wide exposure of S. of N in a rump access according to Radziyevsky (fig. 3) is most reasonable. On a hip the nerve is bared on the projective line drawn from the middle of distance between a sciatic hillock and a big spit down on the middle of a popliteal space, the biceps of a hip is delayed in an upper third of a hip of a knutra, and in lower — knaruzh (fig. 4). Stages of imposing epinevralyggo a seam do not differ from standard. During the imposing of a perineural seam it is necessary to consider that S. of N consists of a set of bunches and it is important to avoid connection of motive bunches with sensitive and vice versa.

At the closed S.'s damages by N conservative treatment using thermal procedures is shown, to electrostimulation, by LFK, massage for a long time. It is necessary to prevent development of vicious provisions of foot and fingers by means of bandages, tires, and also orthopedic footwear.

S.'s damages by N differ in the big duration of regeneration (3 — 5 years and more) and its insufficient completeness. The level of damage is higher, the recovery is less full. After an epinevralny seam in a rump and in proximal departments of a hip of a complete recovery of an innervation of muscles of foot it is not observed, pains in a sole are often noted, however patients adapt to the available frustration. The hyperpathia and paresthesias can be facilitated, having correctly picked up footwear with a firm sole and a soft insole.

Diseases Pages of N are shown a wedge, a picture of neuralgia (ischialgia) and neuritis (sciatica). At neuralgia patol. process is more often limited to a perineural cover, causing a syndrome of irritation. S.'s neuritis of N develops during the involvement in patol. process, except a perineurium, and a parenchyma of a nerve.

In a wedge, a picture of neuralgia of S. of N into the forefront act aching, and at times tearing, pricking or the thermalgias which are localized in the beginning on a back surface of a hip and extending to a shin and foot. At damage of a nerve on a high level (above a buttock fold) pains arise in poyasnichnoyagodichny area with distribution on a hip and a shin. More often pains develop gradually, less often they arise sharply, especially at sharp turns of a trunk, rises in weight, and sometimes are followed by paresthesias (feeling of numbness or crawling of goosebumps, cold sense or a heat, etc.). Pains amplify during the walking, standing or sitting on a rigid chair. In a standing position of the patient leans on a healthy leg, the sore leg is slightly bent.

Points, painful at pressing, are characteristic; they are located between L5 and S1 with vertebrae, on the middle of a buttock, between a big spit of a hip and a sciatic hillock, in a popliteal space, under a head of a fibular bone and on average department of an internal half of a sole. At severe and long pains, especially at patients with neurotic manifestations, the antalgichesky rachiocampsis can develop in the healthy party. Symptoms of Lasega, Bonnet, the Minor are expressed (see. Radiculitis ), Sikar's symptom (at bottom bending of foot there is pain on the course of a fibular nerve), a symptom of Turin (the forced bottom bending of a thumb causes a gastrocnemius muscle pain). A number of tonic pain reflexes comes to light: Vengerov's symptom (a muscle tension of a stomach at the time of a raising of the unbent leg from a dorsal decubitus), involuntary bending of a sore leg in a knee joint upon transition from a prone position to a sitting position, bending of a sore leg at a ducking.

Gait of the patient is peculiar — it goes having bent, lean a hand in a knee of a healthy leg, or moves with a stick, on to-ruyu leans both hands. The sore leg of a polusognut also touches a floor only a sock, the trunk is rejected to the opposite side. The hyperesthesia or decrease in skin sensitivity in a zone of an innervation of S. of N is often noted. Cricks of a biceps of a hip are in some cases possible. Akhillov reflex (see) it is kept or raised. Vasculomotor and secretory disturbances are limited to reddening or blanching of the skin of feet and fingers raised by perspiration.

In mild cases S.'s neuralgia of N under the influence of treatment is successfully stopped, sometimes it is an initial phase neuritis (see), at Krom motive, sensitive and vasculomotor and trophic frustration join symptoms of irritation.

In a wedge, a picture of neuritis of S. of N symptoms of decrease or loss of function of a nerve prevail. At S.'s defeat the N above a buttock fold decreases the volume of gluteuses and there comes paresis of back group of muscles of a hip owing to what there is impossible a bending of a shin.

At damage of a fibular nerve reduction of volume and decrease in a tone of peroneal group of muscles, restriction of a dorsiflexion of foot and fingers, droop of foot and its turn inside is noted (pes equinovarus) owing to what appears peroneal, or «cock», gait — the patient highly raises a leg not to touch about a floor with the hanging-down foot. Walking on heels is complicated or impossible. Skin sensitivity is unsharply broken on an outer surface of a shin and foot. Akhillov and knee reflexes are kept.

During the involvement in patol. process of a tibial nerve megalgias and unpleasant paresthesias on a back surface of a shin and a sole, and also loss of skin sensitivity in the same zone are observed. Reduction of volume of gastrocnemius muscles and muscles of a sole therefore the arch of foot goes deep is noted and fingers adopt the sharp-clawed provision (pes calcaneus). Walking on fingers is impossible owing to paresis of gastrocnemius muscles. Vazomotornosekretorny frustration are expressed as pallor or cyanosis of fingers of foot and disturbance in them of sweating and thermal control (humidity, decrease in skin temperature). In hard cases are noted a hair loss on shins or a local hypertrichosis, fragility of nails, trophic ulcers of foot. Akhillov the reflex, a periosteal reflex from a calcaneus, and also a medioplan-tare reflex drop out; knee jerk (see) it can be raised.

Neuralgia and S.'s neuritis and. it is necessary to differentiate first of all with syphilitic defeat of roots of spinal nerves (see. Syphilis , Back tabes ), and also with a meningoradiculitis, a lumbosacral plexitis, a polyradiculoneuritis and some other diseases, at to-rykh morbidity in lumbosacral and buttock areas is observed. At a meningoradiculitis (see. Radiculitis ) pains usually bilateral also go beyond S.'s innervation of N, in cerebrospinal liquid (see) the pleocytosis is possible. A lumbosacral plexitis (see. Lumbosacral texture ) differs in localization of pains in a rump and on a front surface of a hip, weight loss of muscles of a hip and shin, and also decrease knee and an akhillova of reflexes is quite often observed. For a polyradiculoneuritis (see. Polyneuritis ) multiple defeat of peripheral nerves, sometimes proteinaceous and cellular dissociation and a xanthochromia of cerebrospinal liquid is characteristic. At a long and recurrent current it is necessary to exclude diseases of a backbone and bodies of a small pelvis. Morbidity in lumbosacral area at axial loading is characteristic of tubercular spondylitis (see), and at percussion on a big spit of a hip and heel — for coxitis (see). At localization of pain in a rump it is necessary to exclude existence patol. the center in a small basin (a tumor, a parametritis, a bend of a uterus, etc.).

In the acute period at observance of a bed rest carry out thermal procedures on area of a sacrum or a hip in the form of hot-water bottles and mustard plasters, appoint banks, sollyuks, light bathtubs, a diathermy, etc. in combination with analgetics. At megalgias resort to intravenous administration of 0,5% of solution novokaind or to futlyarny to novocainic blockade (see). The analgesic effect occurs also at intramuscular administration of vitamin of Vg and novocainic skin infiltration across Astvatsaturov. Widely use physical therapy: uv radiation in erythema doses, Bernard's currents, iono-galvanization with novocaine, potassium iodide or lithium on area of a sacrum or a hip. At persistent pains the positive effect occurs from perineural injections of isotonic solution of sodium chloride in mix * from 0.25% solution of novocaine or epidural administration of the same solutions. At neuritis of proximal department of S. and., connected with osteochondrosis of a backbone, wearing the fixing belt is shown, extension (see), and in some cases operative measure. At long and recurrent forms of neuritis it is shown a dignity. - hens. treatment with use of balneological factors: hydrosulphuric bathtubs, including and thermal (Sochi — Matsesta), radonic bathtubs (Tsqaltubo), sulfur baths, gryaze-torfolecheny, paraffin and ozo-keritovy applications (Pyatigorsk, Saky, Yevpatoria, Odessa, etc.).

The forecast at timely treatment favorable. However a recurrence is frequent. Permanent disability meets seldom.

For the prevention of a recurrence of a disease it is necessary to avoid overcooling or overheating, excessive load of a backbone. It is necessary to observe strictly preventive measures in operating time, connected with unfavorable conditions (dampness, cold, forced position of a body, etc.). Early detection of diseases of female generative organs is necessary for timely prevention and treatment of complications. Medical examination for the prevention of a recurrence of a disease and transition of easy forms to heavy is of great importance.

During the definition of extent of disability consider the frequency and duration of a recurrence, their communication with character and working conditions.

Tumors can be found at any level C. of N of Nek-rye from them, napr, neurinoma (see) and neurofibroma (see), move apart or remove not struck bunches of nerve fibrils. Sometimes tumor, e.g. lipoma (see), infiltrirut vnut-ristvolny cellulose C. of N. Other tumors, napr, a malignant shvannoma (see. Neurinoma ) and sarcoma (see), infiltrirut cellulose, sprout a perineurium and destroy nerve fibrils.

At the tumors which are not sprouting bunches of nerve fibrils, a wedge, the picture usually develops slowly. Pains, as a rule, do not arise, parestetichesky feelings are insignificant, and disturbances of conductivity are insignificant. The tumors having infiltrative growth grow quickly, in a wedge, to a picture pains, losses of sensitivity and movements are noted.

Treatment operational. Removal of the tumors which are not burgeoning in nervous bunches can be made without resection of not struck bunches, to-rye atraumatic allocate after a section of an epineurium and otslaivat from a tumor. Losses of sensitivity and movements are not caused by usually operational treatment. Tumors with infiltrative growth exsect together with a nervous trunk within healthy fabrics.

A recurrence after removal of single neinfiltriruyushchy tumors is usually rare. After an operative measure concerning the tumors consisting of multiple nodes, napr at neurofibromatosis (see), a recurrence is frequent, the malignancy, acceleration of growth of the remained nodes, emergence of new nodes of a tumor in other areas of a body is sometimes possible. The forecast at malignant tumors of S. of N adverse.

Bibliography: Bogolepov N. K., etc. Nervous diseases, page 197, M., 1956; Grigorovich K. A. Surgical treatment of injuries of nerves, JI., 1981; Yeremeyev V. S. and Yeremeyeva A. A. To the mechanism of trophic influence of a motor nerve on a skeletal muscle, Fiziol. shurn. USSR, t. 59, No. 10, page 1494, 1973; Kaverina V. V. and Rozhkov E. N. Topografo-anatomi-cheskiye of relationship of a sciatic nerve with nerves of a rump, Uchen. zap. Petrozavodsk, un-that, t. 19, century 7, page 63, 1973; Kanareykin K. F. Lumbosacral pains, page 18, M., 197 °; M. B. and Fedorov E. A. Crawl. Main neuropathological syndromes, page 76, 199, M., 1966; JI at about c to and y D. N, Fundamentals of topographical anatomy, M., 1953; The Multivolume guide to neurology, under the editorship of S. N. Davidenkov, t. 1, book 1, page 307, M., 1955, t. 3, book 1, page 117, M., 1962; Experience of the Soviet medicine in the Great Patriotic War of 1941 — 1945, t. 20, page 31, M., 1952; R at with e c to and y I. I. Vegetative nervous disturbances, page 210, M., 1958; A. V Triumphs. Topical diagnosis of diseases of a nervous system, page 231, JI., 1974; Flat I. M. To a question of anatomy of circulatory system of the lower extremity of the person at damage of a sciatic nerve, in book: Aktualn. vopr. patol. bodies of blood circulation, page 126, Barnaul, 1971; F at - t e r D. S. Lumbosacral radiculitis, M., 1940; Shamburov D. A. Sciatica, page 46, M., 1954; S e d d about n H. J. Surgical disorders of the peripheral nerves, Edinburgh, 1972; Sunderland S. Nerves and nerve injuries, p. 1161, Edinburgh — L., 1972; V i 1 1 i g e r E. Die periphere Innervation, Basel — Stuttgart, 1957.

K. F. Kanareykin; K. A. Grigorovich (injuries., PMC.), N. V. Krylova (An.).