home Audience 6 Innervation zone of the peroneal nerve. Treatment of the peroneal nerve: neuropathy, neuropathy, axonopathy, neuralgia, neuritis and damage. Nervus fibularis communis recovers quite quickly

Innervation zone of the peroneal nerve. Treatment of the peroneal nerve: neuropathy, neuropathy, axonopathy, neuralgia, neuritis and damage. Nervus fibularis communis recovers quite quickly

Peroneal nerve neuropathy develops when it is compressed or damaged. Depending on the location of the injury, the symptoms of this disease vary, but in general, neuropathy is characterized by pain, sensory disturbances, weakness or muscle paresis. This article will discuss the symptoms and treatment, including exercise, of this disease.

Speaking about diseases of the peroneal nerve, you need to have an idea of where it is located and how it works.

The common peroneal nerve is a branch of the sciatic nerve that arises from the sacral plexus. The sciatic nerve divides into the peroneal and tibial nerves at the popliteal fossa.

The common peroneal nerve is located on the outside of the leg, it goes down the leg and is divided into two large branches: superficial and deep, and small branches that are responsible for sensitivity on the outside of the leg. These branches unite with others and extend further to the outer edge of the foot.

The deep part of the peroneal nerve is responsible for the movements of the tibialis anterior muscle, the extensor of the toes and, separately, the extensor of the first digit. It then runs along the foot and ends at the first and second toes.

The superficial part is divided into cutaneous branches, responsible for sensitivity and going to the first, second and third toes, and muscle branches, responsible for the movements of the pennate muscles of the leg. A separate branch innervates all toes except the big toe. Such a complex course of the nerve leads to its vulnerability.

The causes of peroneal nerve neuropathy can vary.

Injuries - the location of the nerve on the surface of the leg means that it is relatively easily damaged as a result of injuries to the upper outer part of the leg. Post-traumatic neuropathy of the peroneal nerve is also called traumatic neuritis. It can occur as a result of injury, fracture, joint dislocation, joint surgery, needle penetration during intramuscular injection, falls, blows, compression by scar tissue after injuries and operations. Its integrity can be violated up to a complete break. When a fracture occurs, the nerve can be damaged by bone fragments, and it can also be compressed by a plaster cast. If the peroneal nerve is damaged, muscle paresis or paralysis may occur.
Tunnel syndromes. More often they occur when staying in a squatting position for a long time or during monotonous leg movements. At risk are people in professions whose work involves staying in this position for a long time. Carpal tunnel syndrome can also occur when sitting cross-legged for a long time. Tunnel syndrome can be caused by compression of a nerve by an intervertebral disc (spondylogenic tunnel syndrome).
Incorrect position of the legs during forced long-term immobility (in bedridden patients, during long operations).
Impaired blood supply.
Toxic lesions (with severe renal failure, diabetes mellitus, alcoholic lesions), in which both legs are affected in a “sock” type.
Severe infections.
Tumor compression and metastases in cancer.

The peroneal nerve can be affected in different areas, so the symptoms will vary. They can be divided into motor and sensory.

With high compression (in the popliteal fossa), the following symptoms occur:

Sensitivity on the anterolateral surface of the leg and the back of the foot is impaired; sensations of touch, heat and cold, and the distinction between pain and touch may be absent.
Pain on the lateral surfaces of the foot and lower leg, intensifies when squatting.
The extension of the foot is impaired, and the extensor muscles can completely fail.
Elevation of the outer edge of the foot is impaired and becomes impossible.
The patient cannot stand on his heels or walk on them.
“Horse foot” - the foot hangs down. When walking, the patient is forced to raise his leg high so as not to cling to the ground with his toes. When stepping, first the toes are placed on the ground, and then the entire leg (steppage, “cock walk”, “horse walk”).
With prolonged illness, muscle atrophy is observed, the diseased leg becomes thinner than the healthy one.

If the outer skin part is compressed, then the symptoms are only sensitive: sensitivity on the outer surface of the lower leg is impaired.

If the superficial branch is damaged, the symptoms will be as follows:

Pain and burning at the bottom of the lateral surface of the leg, in the back of the foot, in 1-4 fingers.
Loss of sensitivity in these same areas.
It is difficult to lift and abduct the outer edge of the foot.
Damage to the deep branch manifests itself as follows.
The muscles responsible for extending the foot and toes fail.
Decreased sensitivity between 1-2 toes on the back of the foot.
Slightly drooping foot.
With long-term illness - atrophy of the foot muscles. Compared to a healthy leg, the bones are more noticeable and the spaces between the toes are sunken.

It is important for the patient to remember that the disease can progress with little or no pain. An important symptom of this disease is the inability to stand or walk on your heels.

Electroneuromyography and ultrasound are used for accurate diagnosis.

Neuropathy of the tibial nerve can be combined with damage to the peroneal nerve. Both of them can be affected at the level of the head of the fibula. The following symptoms are noted:

Numbness on the outside of the foot.
“Spanking” foot is a gait disorder. Weakness of the muscles that flex the foot; it is difficult for the patient to turn the foot outward.
When pinched in the tarsal canal and ankle, pain and tingling on the sole and near the base of the fingers and numbness are observed.
When the plantar branches are involved, sensitivity on the lateral or inner surfaces of the foot is impaired.

Treatment for neuropathy depends on its cause and the area where the nerve is affected. Sometimes it is enough to remove the cause of the compression (plaster cast, uncomfortable shoes).

If neuropathy is caused by another disease, the main focus will be its treatment, and other measures, although also mandatory, are secondary.

Medicines used:

non-steroidal anti-inflammatory drugs (Ibuprofen, Nimesulide, Diclofenac),
drugs that improve nerve conduction (Prozerin, Neuromidin),
B vitamins (their combinations: Milgamma, Combilipen and others),
drugs that improve blood circulation,
antioxidant agents.

Physiotherapy is also used:

magnetic therapy,
amplipulse,
ultrasound therapy,
electrophoresis,
electrical stimulation for paresis and paralysis.

Acupuncture, massage and exercise therapy are also effective.

If there is significant compression, surgical treatment is indicated. In this case, the structures that compress the nerve are removed and the canal in which it passes is expanded. After surgery, the nerve function is restored using conservative methods.

The operation is also indicated for traumatic damage to the nerve, when its regeneration does not occur, for example, when it is interrupted. In this case, its integrity is restored surgically. The sooner such an operation is performed, the better its effect and the more complete the recovery.

To fix the foot in the correct position (correction of the “horse foot”), special orthoses are used.

Physiotherapy

The exercises chosen for physical therapy depend on the preservation of muscle function. The exercises are aimed at restoring plantar and dorsal flexion of the foot and improving blood circulation.

The most effective exercises are performed on special simulators in a physical therapy room, selected taking into account the patient’s condition. The doctor will individually select a complex that the patient can perform at home, having mastered it with an instructor. Self-medicating with exercise can cause further nerve damage. The same goes for therapeutic massage.

Peroneal nerve neuropathy can occur for a variety of reasons. This disease takes a long time to be treated, and the prognosis depends, among other things, on its duration. Therapy should be comprehensive; if nerve damage is the result of another disease, then it is treated first, while simultaneously restoring the function of the nerves and muscles of the leg. In some cases, conservative treatment is ineffective and surgery is required.

Before considering the functions of the peroneal nerve, it is necessary to consider the main branches of the “peroneal nervous system”, the levels of their origin, and then summarize the functions of the peroneal nerve (motor and sensory).

The initial structure of the “peroneal nervous system” is the common peroneal nerve (Latin: n. fibularis communis).

The common peroneal nerve is a direct continuation of the sciatic nerve (n. ischiadicus) [see. schematic representation of the peroneal nerve]. The place of transition of the “peroneal part” of the sciatic nerve into the common peroneal nerve in typical cases is the proximal apex of the popliteal fossa, from where the common peroneal nerve is directed to its lateral side towards the neck of the fibula. In this area, the (1) external (lateral) cutaneous nerve of the calf (shin) - n. cutaneus surae lateralis (which subsequently, when (1.1.) unites at the level of the lower third of the leg with a branch of the tibial nerve - with the medial cutaneous nerve of the calf - n. cutaneus surae medialis - forms the sural nerve - n. suralis *). Lateral cutaneous nerve of the calf - n. cutaneus surae lateralis - innervates the skin of the lateral (side) part of the leg.

When reaching (7) the head of the fibula, the common peroneal nerve bends around it, being covered here only by fascia and skin. At this level, the common peroneal nerve gives off (2) non-permanent articular branches to the lateral parts of the knee joint capsule, as well as to the tibiofibular joint.

Then, reaching and bending around the neck of the fibula, the common peroneal nerve divides into its two branches: (3) the superficial peroneal nerve (n. fibularis superficialis) and (4) the deep peroneal nerve (n. fibularis profundus).

(3) The superficial peroneal nerve (n. fibularis superficialis) is directed down the anterior outer surface of the leg, giving branches to the peroneal muscles ((3.1.) 2-4 branches from the proximal parts of the nerve trunk to the long peroneal muscle and (3.2.) 1-2 branches from the nerve trunk in the middle third of the leg to the peroneus brevis muscle), which abduct and elevate the outer edge of the foot (that is, they pronate the foot while simultaneously dorsiflexing it). At the level of the lower third of the shin The superficial peroneal nerve is divided into two branches, namely into two dorsal cutaneous nerves of the foot - medial and intermediate: (3.2.) n. cutaneus dorsalis medialis and (3.1.) n. cutaneus dorsalis intermedius. The medial dorsal cutaneous nerve of the foot innervates the skin of the inner edge and part of the dorsum of the foot on its medial side, the medial part of the first toe** of the foot (proximally to the interphalangeal joint), as well as the surfaces of the second and third toes facing each other. The intermediate dorsal cutaneous nerve of the foot innervates the skin of the lower third of the leg and dorsum of the foot (middle zone), as well as the dorsal surface between the III - IV, IV - V fingers (proximally to the distal interphalangeal joints).

(4) The deep peroneal nerve (n. fibularis profundus) in the upper parts of the leg gives off (4.1.) branches to the long extensor digitorum muscle (extends the II - V fingers and foot in the ankle joint, abducts and pronates the foot) and the tibialis anterior muscle (extends the foot in the ankle joint, adducts and raises its inner edge - supination), and in the lower parts of the leg it gives off (4.2.) a branch to the long extensor pollicis (extends the first toe and the foot in the ankle joint, supinating it). It should be noted that the deep peroneal nerve has (5) non-permanent connecting branches with the superficial peroneal nerve. When moving to the dorsum of the foot (and giving off the non-permanent (4.5.) articular branch to the capsule of the ankle joint in the transition), the deep peroneal nerve is divided into two branches - lateral (external) and medial (internal). (4.3.) The lateral branch innervates the short extensor muscles of the fingers, and (4.4.) the internal one innervates the skin of the dorsal surface of the sides of the I and II fingers facing each other (that is, I - II interdigital space) and (4.4.) the short extensor of the first finger (extends I finger and moves it slightly to the side); Also from the medial branch there departs (4.4.) a variable number of thin branches that approach the capsules of the metatarsophalangeal and interphalangeal joints of the first and second fingers from their dorsal surface.

*Please note that some manuals on the anatomy of the nervous system report that the formation of the sural nerve does not involve the lateral cutaneous nerve of the calf (which in this case innervates only the lateral surface of the leg, reaching the area of the lateral malleolus without forming an anastomosis with the medial cutaneous nerve of the calf), and the peroneal connecting branch (r. communicans fibularis), which is either directly a branch of the lateral cutaneous nerve of the calf, or is a branch of the main trunk of the peroneal nerve (that is, it is a branch of the common peroneal nerve).

**Please note that the innervation of the toes is carried out by the superficial and deep peroneal nerves due to their terminal branches: nn. digitales dorsales pedis (dorsal nerves of the toes).

Functions of the peroneal nerve

Motor:

1. extension of the foot at the ankle joint, adduction and elevation of the inner edge of the foot – tibialis anterior muscle 1 – see Fig. 1] (m. tibialis anterior), LIV-SI;

2. extension of the foot at the ankle joint, pronation of the foot – long [ 2 – see Fig. 1] and short peroneus muscles [ 3 – see Fig. 1,2] (m. peroneus longus et brevis), LIV-LV;

3. extension of the II – V fingers and foot at the ankle joint, abduction and pronation of the foot – long extensor digitorum longus (m. extensor digitorum longus), LIV – SI;

4. extension of the first toe and foot at the ankle joint, supination of the foot - long extensor hallucis longus (m. extensor hallucis longus), LIV - SI;

5. extension of the toes - short extensor of the fingers (m. extensor digitorum brevis), short extensor of the big toe (m. extensor hallucis breves).

Sensitive:

1. lateral cutaneous nerve of the calf (n. cutaneus surae lateralis - branch extending from the common peroneal nerve) - innervates the skin of the lateral (side) part of the leg;

2. medial dorsal cutaneous nerve: innervates the skin of the inner edge and part of the dorsum of the foot on its medial side, the medial part of the first toe (proximally to the interphalangeal joint), as well as the surfaces of the second and third toes facing each other;

3. intermediate dorsal cutaneous nerve: innervates the skin of the lower third of the leg and dorsum of the foot (middle zone), as well as the dorsal surface between the III - IV, IV - V fingers (proximally to the distal interphalangeal joints);

4. medial branch of the deep peroneal nerve: innervates innervates the skin of the dorsal surface of the sides of the 1st and 2nd fingers facing each other (that is, the 1st - 2nd interdigital space).

Clinical and diagnostic findings

Phenomenology of “storey lesion” of the peroneal nerve(MN). As a rule, MN is neuropathized by a compression-ischemic (tunnel) mechanism at the upper and lower levels (“floors”).

Top floor : level of the neck* of the fibula – damage to the common peroneal nerve (total neuropathy of the MN) – the clinical picture is characterized by
1. paralysis of foot extension (dorsial flexion);
2 paralysis of adduction of the foot inward and elevation (supination) of its inner edge;
3. paresis of abduction of the foot and elevation of its outer edge (pronation);
4.. deep paresis of the toe extensors;
5. atrophy (hypotrophy) of the muscles of the anterior outer surface of the leg (peroneus anterior muscle, long extensor of the first toe;
6. pain and paresthesia in the anterior outer parts of the leg, on the back of the foot and fingers, or anesthesia (hypoesthesia) in this area;
7. unexpressed vasomotor and trophic disorders;

The phenomenon of the upper floor is characterized by: foot drop (stepping - pes equino varus - peroneal, rooster, horse gait) and “lazy toes”; inability to stand on your heels and walk on them, “loss of weight in the lower leg” (due to its anterior outer surface).

* PLEASE NOTE: at the level of the neck of the fibula, “there is” only a division of the common peroneal nerve into superficial and deep branches, and the external cutaneous nerve of the calf, which is also a branch of the common MN (and is involved in the formation of the n. suralis and supplies sensitivity to the upper half of the anterolateral part of the skin of the leg) departs from the general MN above the neck of the fibula - in the popliteal fossa, therefore, with compression cervicofibular pathology, there are no sensitivity disorders on the upper half of the anterolateral surface, but there is only a sensitivity disorder on the lower half of the anterolateral part of the leg and on the dorsum of the foot (from superficial and deep MN-s).

Ground floor: = 1. dorsum of the ankle joint with the lower extensor retinaculum (ligament) (referred to as anterior tarsal syndrome) + 2. base of the metatarsal bone (referred to as inferior tunnel syndrome MN); = => compression-ischemic lesion of the deep peroneal nerve; the clinical picture depends on the damage to the branches of the deep peroneal nerve:

[isolated] damage to the outer (lateral) branch (deep branch MN):
1. conductor fibers of deep sensitivity are irritated and poorly localized pain occurs on the back of the foot;
2. paresis and atrophy of the small muscles of the foot (innervated by the MN) develops;
NB – no impairment of skin sensitivity;

[isolated] damage to the internal (medial) branch (deep branch MN):
1. symptoms of impaired superficial (skin) sensitivity in the Ι first interdigital space and adjacent surfaces of the Ι and ΙΙ fingers dominate;
2. pain and paresthesia may be felt only in the Ι - ΙΙΙ toes, especially if there is no retrograde spread of pain and paresthesia;
NB – no motor (movement) disorders;

Under the inferior extensor ligament of the foot is most often compressed common trunk of deep MN or both its branches(external and/or internal) [= joint lesion] - the clinical picture is determined by the sum of symptoms of damage to the external and internal branches:
1. the upper level of provocation of painful sensations on the back of the ankle joint;
2. paresis of the extensor digitorum brevis;
3. hypoesthesia in the skin zone of the internal branch of the deep MN.

As you can see, the “number of floors” of MN lesions is mainly associated (in educational publications and manuals on neurology) only with general MN and deep MN (with its branches). Participation in the “mid-rise” of the surface branch of the MN is not specifically considered anywhere. The essence middle floor consists of damage at this level (more precisely in the lower part of the lower third of the leg) of the superficial peroneal nerve as it passes through the fibrous opening in the fascia of the leg (see arrow pointer (A)) after which it divides into two branches, namely two dorsal cutaneous nerves of the foot - medial and intermediate.

Also at the level of the middle-lower third of the leg it is possible to develop traction neuropathy of the superficial peroneal nerve (Henry's peroneal mononeuralgia) . The syndrome is caused by hyperangulation of the nerve passing through the fibrous opening in the fascia propria of the leg, and its traction during forced plantar flexion of the foot and its medial rotation. Damage to the superficial peroneal nerve leads to weakened abduction and elevation of the outer edge of the foot. The foot is slightly adducted, its outer edge is lowered. Extension of the foot and fingers is possible, since the innervation of the extensors of the foot and fingers by the branches of the deep peroneal nerve is preserved. Sensitivity disorders of the dorsum of the foot are noted, with the exception of the first interdigital space (innervation is carried out by the cutaneous branches of the deep peroneal nerve) and the outer edge of the foot (innervation is carried out by the branches of the sural nerve).

Middle floor syndrome in relation to the peroneal nerve may occur anterior tibial syndrome(in the middle third of the shin + slightly lower and slightly higher) - where the deep branch of the MN passes in the muscles indicated below. The tibialis anterior muscle, extensor pollicis longus, and extensor digitorum longus are enclosed in a closed osteofascial sheath. It also contains the deep peroneal nerve, an artery and two veins. These muscles are deprived of any significant collateral circulation, which determines the increased vulnerability of this muscle group. A mechanical obstruction to blood flow can be caused by occlusion or thromboembolism of the great vessels of the legs. Edema with compression of arterioles and capillaries can develop in response to excessive stress that is not accompanied by an adequate increase in blood supply (long walking, running, dancing). Intense local pain occurs against the background of redness and dense swelling of the pretibial area. Paralysis of the extensors of the foot and fingers gradually develops. At the height of the disease, clear signs of sensory impairment are found in the zone of innervation of the deep peroneal nerve: numbness and hypoesthesia on the dorsum of the first interdigital space of the foot.

© Laesus De Liro

Name

Common peroneal nerve(lat. Nervus fibularis communis) - nerve of the sacral plexus. It is formed after the division of the sciatic nerve in the area of the popliteal fossa into two parts. Formed by fibers L IV, L V, S I, S II nerves.

From the proximal apex of the popliteal fossa it goes to its lateral side and is located under the medial edge of the biceps femoris muscle, between it and the lateral head of the gastrocnemius muscle, spiraling around the head of the fibula, being covered here only by fascia and skin. In this area, non-permanent articular branches extend from the nerve trunk to the lateral parts of the knee joint capsule. Distally, it penetrates into the thickness of the initial part of the peroneus longus muscle, where it divides into its two terminal branches - the superficial and deep peroneal nerves.

Branches of the nerve [ | ]

From the common peroneal nerve arise:

Peroneal nerve neuropathy often occurs in children and adults. To make a diagnosis, examinations are also needed.

The common peroneal nerve (n. peroneus communis, L4-L5, S1-S2) is the second terminal branch of the sciatic nerve; before it splits into terminal branches, the external cutaneous nerve departs from the common peroneus communis, innervating the lateral and posterior surface of the leg, and also forms an anastomosis with the medial cutaneous nerve of the leg, which gives rise to the sural nerve (described above). Next, the common peroneal nerve approaches the neck of the head of the fibula, where it splits into its terminal branches, forming the superficial, deep and recurrent nerves.

Portrait of a young girl enjoying a healthy skin treatment at a spa resort.

The superficial peroneal nerve innervates the long and short peroneus muscles (elevate and abduct the outer edge of the foot). At the level of the middle third of the leg, the superficial branch exits under the skin, forming the medial dorsal cutaneous nerve (innervates the inner edge of the foot, 1st toe and 2nd interdigital space) and the intermediate dorsal cutaneous nerve (innervates the lower third of the leg, dorsum of the foot and 3rd and 4th interdigital spaces).

The deep peroneal nerve innervates the extensor digitorum longus (extends digits 2-5 and the foot at the ankle joint, simultaneously pronates and abducts the foot), the tibialis anterior muscle (extends the foot at the ankle joint, adducts and elevates the inner edge of the foot), extensor hallucis longus (extends big toe and takes part in extension of the foot at the ankle joint). On the foot, the deep peroneal nerve innervates the short extensor of the digitorum (extends 2-5 fingers), the short extensor of the 1st toe (extends 1 toe and abducts it outward) and 1 interdigital space.

When the common peroneal nerve is damaged, the extension of the foot in the ankle joint and pronation of its outer edge are impaired, and a “horse foot” is formed - manifested by persistent plantar flexion of the foot. A steppage or “cock gait” appears, in which the patient, so that the back of the foot does not touch the floor, raises his legs high; when lowering the lower limb, the surface first touches the fingers, and then the entire foot. There is atrophy of the muscles of the anterior outer surface of the leg, in the same area there is a sensitivity disorder, on the foot there is hypoesthesia on the dorsal surface, which includes 1 interdigital space.

Treatment of neuropathy of the peroneal nerve should be comprehensive and include the use of medications, physiotherapy, massage, exercise therapy, electrical and magnetic stimulation, reflexology, and water treatments.

1. Internal obturator nerve, n. obturatorius internus, arises from the lumbosacral trunk and the anterior branch of the first sacral nerve (SI). Having left the pelvis under the piriformis muscle, the nerve bends around the ischial spine, approaches the obturator internus muscle, sometimes giving a small branch to the superior gemellus muscle.

2. Nerve of the piriformis muscle, n. piriformis, formed by two trunks extending from the posterior surface of the anterior branches of the first and second sacral nerves (SI, SII); With a common trunk, the nerve approaches the piriformis muscle and innervates it.

3. Nerve of the quadratus femoris muscle, n. quadratus femoris, originates from the anterior surface of the lumbosacral trunk and the first sacral nerve. Coming out of the pelvis under the piriformis muscle, it gives off terminal branches to the quadratus femoris muscle. Descending slightly in front of the sciatic nerve, it sends branches to the twin muscles and the capsule of the hip joint.

4. Superior gluteal nerve, n. gluteus superior(LIV, LV, SI), leaves the pelvic cavity, accompanied by the vessels of the same name, through the gap above the piriformis muscle and, bending around the greater sciatic notch, lies between the gluteus medius and minimus muscles, moving in an arched manner forward. Having given branches to the indicated muscles, the nerve is distributed with its terminal branches in the thickness of the tensor fascia lata.

5. Inferior gluteal nerve, n. gluteus inferior(LV, SI, SII), leaves the pelvic cavity through the gap under the piriformis muscle into the gluteal region under the gluteus maximus muscle along with the pudendal nerve (lateral to it), the sciatic nerve and the posterior cutaneous nerve of the thigh (medial to them). It branches in the thickness of the gluteus maximus muscle, also innervating the capsule of the hip joint. Sometimes the nerve takes part in the innervation of the obturator internus, gemellus and quadratus femoris muscles.

6. Posterior cutaneous nerve of the thigh, n. cutaneus femoris posterior, initially adjacent to the inferior gluteal nerve or along a common trunk with it; exits the pelvic cavity through a gap under the piriformis muscle medial to the sciatic nerve and lies under the gluteus maximus muscle, located almost in the middle between the ischial tuberosity and the greater trochanter of the femur, and descends to the posterior surface of the thigh. Here it is located immediately under the fascia lata, corresponding to the groove between the semitendinosus and biceps femoris muscles; heading down, it gives off branches that extend on both sides of the main trunk and pierce the fascia along the back of the thigh. The branches branch in the skin of the posterior and especially medial surfaces of the thigh, reaching the skin of the popliteal fossa.

Branches of the posterior cutaneous nerve of the thigh:

1) lower nerves of the buttocks, nn. clunium inferiores, moving away from the main trunk with 2-3 branches, bend around or pierce the lower edge of the gluteus maximus muscle, go upward and branch in the skin of the gluteal region;

2) perineal branches, rr. perineales, only 1-2, sometimes more - thin nerves, depart from the main trunk, go down and, bending around the ischial tuberosity, follow anteriorly, branching in the skin of the medial surface of the scrotum (labia majora) and perineum. These branches connect with the branches of the pudendal nerve of the same name.

7. Sciatic nerve, n. ischiadicus(LIV, LV, SI - SIII) - the thickest nerve not only of the lumbosacral plexus, but of the entire body; is a direct continuation of all the roots of the sacral plexus. Upon exiting through the gap under the piriformis muscle, the sciatic nerve is located lateral to all the nerves and vessels passing through this opening, and lies between the gluteus maximus muscle on one side and the gemelli, internal obturator muscles and quadratus femoris muscle on the other, almost in the middle of the line drawn between the ischial tuberosity and the greater trochanter of the femur. Even before exiting through the gap, an articular branch departs from the sciatic nerve to the capsule of the hip joint.

Coming from under the lower edge of the gluteus maximus muscle, the sciatic nerve is located in the region of the gluteal fold close to the fascia lata of the thigh; further down it is covered by the long head of the biceps femoris muscle, located between it and the adductor magnus muscle. In the middle of the thigh, a long head crosses it; below it is located between the semimembranosus muscle medially and the biceps femoris muscle laterally and reaches the popliteal fossa, where in its upper corner it is divided into two branches: a thicker medial one - the tibial nerve and a thinner lateral one - the common peroneal nerve.

The division of the sciatic nerve into these two branches can sometimes occur above the popliteal fossa, even directly at the sacral plexus itself. In this case, from the pelvic cavity, the tibial nerve passes under the piriformis muscle, and the common peroneal nerve can pierce this muscle or pass over it. Both of these branches, throughout the entire sciatic nerve, lie in a common connective tissue sheath, after opening which, it is easy to separate them to the sacral plexus. Along the line of contact of the tibial and common peroneal nerves passes the artery accompanying the sciatic nerve.

Branches of the sciatic nerve:

1) muscle branches, rr. musculares, branch in the following muscles: m. obturatorius interims, mm. gemelli superior et inferior, m. quadratus femoris.

The muscular branches arise either before or within the passage of the sciatic nerve through the foramen under the piriformis muscle. In addition, muscle branches in the thigh area extend from the tibial part of the sciatic nerve to m. biceps femoris (caput longum), m. semitendinosus, m. semimembranosus, m. adductor magnus. From the peroneal part of the sciatic nerve, the muscle branches go to m. biceps femoris (caput breve);

2) articular branches depart from the tibial and peroneal parts of the sciatic nerve to the articular capsule of the knee joint;

3) common peroneal nerve, n. fibularis communis(LIV, Lv, SI, SII), from the proximal apex of the popliteal fossa goes to its lateral side and is located under the medial edge of the biceps femoris muscle, between it and the lateral head of the gastrocnemius muscle, spirals around the head of the fibula, being covered here only by fascia and skin .

In this area, non-permanent articular branches extend from the nerve trunk to the lateral parts of the knee joint capsule, as well as to the tibiofibular joint. Distal to this area, it penetrates into the thickness of the initial part of the peroneus longus muscle, where it divides into its two terminal branches - the superficial peroneal nerve and the deep peroneal nerve.

Branches arise from the common peroneal nerve:

a) lateral cutaneous nerve of the calf, n. cutaneus surae lateralis, departs in the popliteal fossa, goes to the lateral head of the gastrocnemius muscle and, piercing the fascia of the leg in this place, branches in the skin of the lateral surface of the leg, reaching the area of the lateral malleolus;

b) fibular connecting branch, r. communicans fibularis, can start from the main trunk or from the lateral cutaneous nerve of the leg, follows the lateral head of the gastrocnemius muscle, located between it and the fascia of the leg, pierces the latter and, branching in the skin, connects with the medial cutaneous nerve of the leg;

c) superficial peroneal nerve, n. fibularis superficialis, passes between the heads of the long peroneal muscle, follows down, located at some distance between both peroneal muscles. Having passed to the medial surface of the peroneus brevis muscle, the nerve pierces the fascia of the leg in the region of the lower third of the leg and branches into its terminal branches: the dorsal medial and intermediate cutaneous nerves (foot).

Branches of the superficial peroneal nerve:

muscle branches, rr. musculares, innervate the peroneus longus muscle (2-4 branches from the proximal parts of the trunk) and the peroneus brevis muscle (1-2 branches from the trunk in the middle third of the leg);

medial dorsal cutaneous nerve, m. cutaneus dorsalis medialis,- one of the two terminal branches of the superficial peroneal nerve. It follows for some distance over the fascia of the leg, goes to the medial edge of the dorsum of the foot, gives off branches to the skin of the medial ankle, where it connects with the branches of the saphenous nerve of the leg, after which it divides into two branches. One of them, the medial one, branches in the skin of the medial edge of the foot and big toe to the distal phalanx and connects in the area of the first interosseous space with the deep peroneal nerve. The other branch, the lateral one, connects with the terminal branch of the deep peroneal nerve and goes to the area of the second interosseous space, where it branches in the surfaces of the II and III fingers facing each other, giving here the dorsal digital nerves of the foot, nn. digitales dorsales pedis;

d) intermediate dorsal cutaneous nerve, n. cutaneus dorsalis intermedius, like the medial dorsal cutaneous nerve, is located over the fascia of the leg and follows the anterolateral surface of the dorsum of the foot. Having given off branches to the skin of the area of the lateral ankle, which connect with the branches of the sural nerve, it is divided into two branches, of which one, going medially, branches in the skin of the surfaces of the third and fourth fingers facing each other. The other, lying more lateral, is directed to the skin of the surfaces of the fourth finger and little finger facing each other and to the lateral surface of the little finger, here forming a connection with the terminal branch of the sural nerve. All these branches are called the dorsal digital nerves of the foot, nn. digitales dorsales pedis;

e) deep peroneal nerve, n. fibularis (peroneus) profundus, piercing the thickness of the initial sections of the long peroneal muscle, the anterior intermuscular septum of the leg and the long extensor of the fingers, lies on the anterior surface of the interosseous membrane, located on the lateral side of the anterior tibial vessels.

Next, the nerve passes to the anterior and then to the medial surface of the vascular bundle, is located in the upper parts of the leg between the long extensor of the digitorum and the anterior tibialis muscle, and in the lower parts - between the anterior tibial muscle and the long extensor of the big toe, innervating them. The deep peroneal nerve has intermittent connecting branches with the superficial peroneal nerve.

When moving to the dorsum of the foot, the nerve passes first under the superior extensor retinaculum, giving a non-permanent articular branch to the ankle joint capsule, and then under the inferior extensor retinaculum and the tendon of the long extensor of the big toe and is divided into two branches: lateral and medial.

The first is shorter, most of its branches are directed to the short extensor fingers. The second branch is longer, accompanied by the dorsal artery of the foot, reaches the area of the first interosseous space, where, passing under the tendon of the short extensor of the big toe together with the first dorsal metatarsal artery, it is divided into two terminal branches, branching in the skin of the dorsum of the sides I and facing each other. II fingers. Along with them, a variable number of thin branches depart, approaching the capsules of the metatarsophalangeal and interphalangeal joints of the first and second fingers from their dorsal surface.

Branches of the deep peroneal nerve:

a) muscle branches, rr. musculares, in the lower leg area are directed to the following muscles: m. tibialis anterior - 3 branches that enter the upper, middle and lower parts of the muscle, to m. extensor digitorum longus and m. extensor hallucis longus - 2 branches each that enter the upper, middle and lower parts of the muscles. In the area of the dorsum of the foot, the muscle branches approach m. extensor digitorum brevis and m. extensor hallucis brevis;

b) dorsal digital nerves, nn. digitales dorsales, - terminal branches of the deep peroneal nerve. They are divided into two nerves: the lateral nerve of the big toe (branches in the skin of the dorsum of the first toe from its lateral edge) and the medial nerve of the second toe (innervates the skin of the dorsum of the toe from its medial edge);

4) tibial nerve, n. tibialis(LIV, Lv, SI, SII, SIII), being in its direction a continuation of the sciatic nerve, much thicker than its second branch - the common peroneal nerve. It begins at the top of the popliteal fossa, follows almost vertically to its distal angle, located in the area of the fossa directly under the fascia, between it and the popliteal vessels.

Further, following between both heads of the gastrocnemius muscle, it lies on the posterior surface of the popliteus muscle and, accompanied by the posterior tibial vessels, passes under the tendinous arch of the soleus muscle, being here covered by this muscle.

Heading further down under the deep layer of fascia of the leg between the lateral edge of the flexor digitorum longus and the medial edge of the flexor hallucis longus, the tibial nerve reaches the posterior surface of the medial malleolus, where it is located midway between it and the calcaneal tendon. After passing under the flexor retinaculum, the nerve divides into its two terminal branches: the medial plantar nerve and the lateral plantar nerve.

Branches of the tibial nerve:

a) muscle branches, rr. musculares, are directed to the following muscles: to the heads of the gastrocnemius muscle (the branch of the medial head is thicker than the lateral one); to the soleus muscle (anterior and posterior branches); to the popliteus muscle, to the plantaris muscle. The branches approaching the popliteus muscle send branches to the capsule of the knee joint and the periosteum of the tibia;

b) interosseous nerve of the leg, n. interosseus cruris, is a rather long nerve, from which, before it enters the thickness of the interosseous membrane, branches are directed to the wall of the tibial vessels, and after leaving the interosseous membrane - to the periosteum of the bones of the leg, their distal connection and to the capsule of the ankle joint, to the posterior tibialis muscle, long flexor big toe, flexor digitorum longus;

c) medial cutaneous nerve of the calf, n. cutaneus surae medialis, departs in the area of the popliteal fossa from the posterior surface of the tibial nerve, follows under the fascia, accompanied by the small saphenous vein running medially between the heads of the gastrocnemius muscle. Having reached the middle of the lower leg, approximately at the level of the beginning of the calcaneal tendon, sometimes higher, it pierces the fascia, after which it connects with the peroneal connecting branch, r. communicans peroneus (fubularis), into one trunk - sural nerve, n. suralis.

The latter runs along the lateral edge of the calcaneal tendon, accompanied by the small saphenous vein located medially from it and reaches the posterior edge of the lateral malleolus, where it sends the lateral calcaneal branches, rr, into the skin of this area. calcanei laterales, as well as branches to the ankle joint capsule.

Next, the sural nerve goes around the ankle and passes to the lateral surface of the foot in the form of the lateral dorsal cutaneous nerve, n. cutaneus dorsalis lateraslis, which branches in the skin of the dorsum and lateral edge of the foot and the dorsum of the fifth toe and gives off a connecting branch to the intermediate dorsal cutaneous nerve of the foot;

d) medial calcaneal branches, rr. calcanei mediates, penetrate the fascia in the area of the ankle groove, sometimes in the form of a single nerve, and branch in the skin of the heel and medial edge of the sole;

e) medial plantar nerve, n. plantaris medialis, - one of the two terminal branches of the tibial nerve. The initial sections of the nerve are located medial to the posterior tibial artery, in the canal between the superficial and deep layers of the flexor retinaculum. After passing through the canal, the nerve is directed, accompanied by the medial plantar artery, under the abductor muscle of the big toe. Following further forward between this muscle and the flexor digitorum brevis, it is divided into two parts - medial and lateral.

The medial plantar nerve gives off several cutaneous branches to the skin of the medial surface of the plantar:

muscle branches to m. abductor hallucis, m. flexor digitorum brevis, m. flexor hallucis brevis and common plantar digital nerves I, II, III, nn. digitales plantares communes I, II, III. The latter are accompanied by the metatarsal plantar arteries, send muscle branches to the first and second (sometimes to the third) vermiform muscles and pierce the plantar aponeurosis at the level of the distal end of the interosseous spaces. Having given thin branches here to the skin of the sole, they are divided into their own plantar digital nerves, nn. digitales plantares proprii, branching in the skin of the sides of the plantar surface of the I and II, II and III, III and IV fingers facing one another, and pass to the dorsal surface of their distal phalanges;

e) lateral plantar nerve, n. plantaris lateralis, is the second terminal branch of the tibial nerve, much thinner than the medial plantar nerve. Passing on the sole, accompanied by the lateral plantar artery, between the quadratus plantaris muscle and the flexor digitorum brevis muscle, it lies closer to the lateral edge of the foot between the flexor digiti brevis muscle and the abductor digiti minimi muscle, where it divides into its terminal branches: superficial and deep.

Branches of the lateral plantar nerve:

muscle branches extend from the main trunk before dividing it into terminal branches and are directed to the quadratus plantae muscle and to the abductor little finger muscle;

superficial branch, r. superficialis Having given several branches to the skin of the sole, it is divided into medial and lateral branches. Medial branch- common plantar digital nerve, n. digitalis plantaris communis (IV and V fingers), which, accompanied by the metatarsal plantar artery, passes through the fourth interosseous space. Approaching the metatarsophalangeal joint and sending a connecting branch to the medial plantar nerve, it divides into two proper plantar digital nerves, nn. digitales plantares propria. The latter branch in the skin of the sides of the IV and V fingers facing one another and pass to the dorsal surface of their nail phalanges. Lateral branch- the own plantar nerve of the fifth finger, which branches in the skin of the plantar surface and the lateral side of the fifth finger. This nerve often gives off muscular branches to the interosseous muscles of the fourth intermetatarsal space and to the flexor of the little finger;

deep branch, r. profundus, accompanied by the plantar arch artery, is located between the layer of interosseous muscles on one side and the flexor digitorum longus and the oblique head of the adductor big toe muscle on the other. It gives off muscle branches to these muscles, to the lumbrical muscles (II, III, IV) and the flexor hallucis brevis (to its lateral head).
In addition to the listed nerves, the superficial and deep branches of the lateral plantar nerve send nerves to the capsules of the metatarsal joints and to the periosteum of the metatarsal bones and phalanges.

8. Genital nerve n. pudendus(SI-SIV), is the caudal part of the sacral plexus and is connected to it by several branches. The nerve lies under the inferior border of the piriformis muscle on the anterior surface of the coccygeus muscle; The lateral sacral vessels pass along its anterior surface in the longitudinal direction.

Nerves, arteries and veins of a woman's perineum; bottom view.

The pudendal nerve is also connected with the coccygeal plexus and with the vegetative inferior hypogastric plexus, due to which its branches take part in the innervation of the internal organs of the pelvic cavity (rectum, bladder, vagina, etc.), the external genital organs, as well as the muscles of the pelvic diaphragm: the levator ani muscle and the coccygeus muscle - and the skin of the perineal area.

Nerves, arteries and veins of the male perineum; bottom view.

The pudendal nerve emerges from the pelvic cavity, accompanied by the internal genital vessels lying medially from it, through the gap under the piriformis muscle. Next, it lies on the posterior surface of the ischial spine, goes around it and, having passed through the lesser sciatic foramen, returns to the pelvic cavity, located below the levator ani muscle, in the ischial-anal fossa, where it runs along its lateral wall, in the thickness of the internal fascia obturator muscle.

In the ischial-anal fossa, the pudendal nerve divides into its branches:

1) inferior rectal nerves, nn. rectales inferiores, are located most medially, following to the perineal part of the rectum, the external sphincter of the anus and to the skin of the anal opening;

2) perineal nerves, nn. perineates, follow along with the vessels of the perineum and are the most superficial of the terminal branches of the pudendal nerve. From the perineal nerves, muscle branches extend to the anterior parts of the external anal sphincter, to the superficial transverse perineal muscle, bulbospongiosus muscle, ischiocavernosus muscle and posterior scrotal nerves, nn. scrotales posteriores (posterior labial nerves, nn. labiates posteriores, - in women), - a superficial group of branches.

These nerves are directed to the skin of the perineum and to the skin of the posterior surface of the scrotum (labia majora in women); connect to the lower rectal nerves, as well as to the perineal branches of the posterior cutaneous nerve of the thigh;

3) dorsal nerve of the penis (dorsal nerve of the clitoris in women), n. dorsalis penis (n. dorsalis clitoridis), is the superior branch of the pudendal nerve. It follows, accompanied by the penile artery, along the inner surface of the lower branch of the ischium and pubis and, passing through the urogenital diaphragm, lies together with the dorsal penile artery on the dorsum of the penis (clitoris in women), where it branches into its terminal branches in the skin and in cavernous bodies of the penis, reaching its head (in women it reaches the labia majora and minora).

On its way, the nerve sends branches to the deep transverse muscle of the perineum, the sphincter of the urethra and the cavernous plexus of the penis (clitoris).