Autonomic nerve plexuses. Nerve plexuses (types) Nerve plexuses on the back

Cervical nerve plexus(lat. plexus cervicalis) is a nerve plexus, a paired formation formed by the anterior branches of the four upper cervical spinal nerves, connected by three arcuate loops. It is located on the anterolateral surface of the deep muscles of the neck (the levator scapulae muscle, the medial scalene muscle, the splenius muscle of the neck) at the level of the four upper cervical vertebrae. In front and on the side it is covered by the sternocleidomastoid muscle. The cervical plexus consists of nerves such as: muscle; cutaneous; phrenic.

It has connections with the accessory and hypoglossal nerves.

Structure and function of the cervical nerve plexus

Motor (muscle) nerves (branches) innervate adjacent muscles: long muscles neck and head, anterior, middle and posterior scalene muscles, anterior and lateral rectus capitis muscles, anterior intertransverse muscles and levator scapulae muscles, as well as the cervical loop (lat. ansa cervicalis). Its formation involves the descending branch of the hypoglossal nerve - the upper root (lat. radix superior (anterior)), containing nerve fibers from the cervical plexus, and the branches extending from the cervical plexus - the lower root (lat. radix inferior (posterior)). The cervical loop is located slightly above the top of the intermediate tendon of the omohyoid muscle, on the anterior surface of the common carotid artery. Nerves arising from the cervical loop innervate the muscles located below the hyoid bone (subhyoid muscles: sternohyoid, sternothyroid, omohyoid, thyrohyoid). Branches of motor nerves depart from the cervical plexus, also innervating the trapezius and sternocleidomastoid muscles.

Cutaneous (sensory) nerves (branches) The cervical plexus bends around the posterior edge of the sternocleidomastoid muscle slightly above its middle and passes to the surface under the subcutaneous muscle of the neck. The cervical plexus gives off cutaneous branches: the greater auricular nerve, the lesser occipital nerve, the transverse cervical nerve and the supraclavicular nerves.

Phrenic nerve cervical plexus (lat. n. phrenicus) is formed from the anterior branches of the cervical spinal nerves, descends down the anterior surface of the anterior scalene muscle and penetrates the thoracic cavity through the superior aperture chest(between the subclavian artery and vein). Initially, both nerves go in the superior mediastinum, then pass into the middle mediastinum and are located on the lateral surface of the pericardium, in front of the root of the corresponding lung. Here the phrenic nerve lies between the pericardium and the mediastinal pleura and ends in the thickness of the diaphragm. The motor fibers of the phrenic nerve innervate the diaphragm, the sensory fibers (pericardial branch (lat. r. pericardiacus)) - the pleura and pericardium. Sensitive diaphragmatic-peritoneal branches (lat. rr. phrenicoabdominales) pass into the abdominal cavity and innervate the peritoneum covering the diaphragm. The branches of the right phrenic nerve pass, without interruption (in transit), through the celiac plexus to the liver.

Brachial nerve plexus(lat. plexus brachialis) is a nerve plexus of 4-8 cervical and 1-2 thoracic spinal nerves, as a result of which nerves are formed shoulder girdle and free upper limb.

Distinguish supraclavicular and infraclavicular parts of the brachial plexus. The supraclavicular part is located in lateral triangle of the neck, and subclavian - in the armpit.

The nerves of the brachial plexus innervate the skin of the upper limb, as well as its muscles.

Lumbar plexus(lat. Plexus lumbalis) - nerve plexus. It is formed from the anterior branches of the three superior and superior parts of the 4th lumbar nerves, as well as branches from the 12th thoracic nerve. Together with the sacral plexus it forms the lumbosacral plexus (lat. Plexus lumbosacralis)

Lies on the side of the transverse processes of the lumbar vertebrae under big psoas muscle and gives rise to a whole series of branches that partly emerge from under the lateral edge, partly from the thickness, and partly from under the medial edge of the muscle.

I. From under the lateral edge muscles come out:

Muscle branches - depart even before the formation of the plexus from the anterior branches of the I-IV transverse nerves to the intertransverse muscles of the lumbar region, to the quadratus lumborum muscle, the large and small lumbar muscles.

Iliohypogastric nerve (lat. Nervus iliohypogastricus)

Ilioinguinal nerve (lat. Nervus ilioinguinalis)

Lateral cutaneous nerve of the thigh (lat. Nervus cutaneus femoris lateralis)

Femoral nerve (lat. Nervus femoralis)

II. From the thickness of the muscle comes out:

Genitofemoral nerve (lat. Nervus genitofemoralis)

III. From under the medial edge of the muscle come out:

Obturator nerve (lat. Nervus obturatorius)

Accessory obturator nerve (lat. Nervus obturatorius accessorius)

Sacral plexus(lat. Plexus sacralis) - nerve plexus. Consists of the anterior branches of the 4th (lower part) and 5th lumbar nerves and the same branches of the four sacral nerves (SI - SIV).

It is a triangular thick plate whose apex is directed towards infrapyriform fissure. Part of the plexus lies on anterior surface of the sacrum, part on anterior surface piriformis muscle .

The plexus is surrounded by loose connective tissue and lies under the parietal layer of the pelvic fascia; on the side of its medial surface there is a number of branches of the internal iliac vessels.

The nerves of the plexus, connecting with each other, form a thick trunk of the sciatic nerve, emerging through the infrapiriform foramen from the pelvic cavity. The branches arising from the sacral plexus can be divided into short and long. The former branch in the region of the lower limb girdle, and the latter supply the entire lower limb, with the exception of that part of it that is supplied with branches of the lumbar plexus.

According to T.F. Lavrova, both lungs are innervated by the branches of the vagus, sympathetic and phrenic nerves. Numerous pulmonary branches of the vagus nerve extend from it along almost its entire length chest cavity, starting from the level of the subclavian artery, and reaching almost to the diaphragm. Sympathetic fibers anteriorly arise from the common cardiopulmonary plexus.
Posteriorly there are permanent posterior pulmonary nerves arising from the 1st to 5th thoracic sympathetic ganglia. The origin and number of these nerves vary greatly.

Phrenic nerve gives the thinnest branches to the mediastinal pleura. In the region of the root of the lungs, the phrenic nerve gives branches to the visceral pleura and along it reaches the lung tissue. Often one of these branches can be traced in the thickness of the visceral pleura to almost half of the anterior surface of the lung.

All these three nerve connected to each other. Moreover, in addition to direct anastomoses, sympathetic nerves and branches of nearby nerves anastomose with each other in the cardiopulmonary plexus (right and left), on back surface root of the lungs, on the esophagus, in the aortic plexus. The branches of this plexus, heading towards the heart, enter the pericardium and form there the intrapericardial plexus, from which branches extend to the vessels and the heart.

The most powerful nerve plexus The posterior mediastinum is the esophageal mediastinum, formed by the right and left vagus and sympathetic nerves. Numerous short branches extend from this plexus to the wall of the esophagus, the pericardium, and the right and left lungs.

Intrapulmonary nerves both the anterior and posterior plexuses follow the course of the vessels and. All of these plexuses are interconnected and functionally represent a single whole.

This short description nerves lungs gives a clear idea of ​​the complex innervation that exists in the chest, of the close connections that exist between the fibers innervating the lungs and heart. This explains the need for extensive, thorough anesthesia of the root of the lung and mediastinum to prevent pleuropulmonary shock.

It should also be noted that in warning this shock great importance has reliable anesthesia of the parietal pleura and parapleural tissue. Clinical observations constantly convince us of this. However, there are still no anatomical and experimental works explaining this situation.

Data on regarding the vagus nerve to the root of the lung, namely: at what distance from the lung tissue within its root lies the vagus nerve. This question is very important for the surgeon. Experience convinces us that the vagus nerve requires a lot of attention. It is very important that it or its large branch does not fall into the ligature. In this regard, there will be much less danger from crossing it than from ligation.

The human nervous system is divided into central, peripheral and autonomic parts. The peripheral part of the nervous system is a collection of spinal and cranial nerves. It includes ganglia and plexuses formed by nerves, as well as sensory and motor endings of nerves. Thus, the peripheral part of the nervous system unites all nerve formations that lie outside the spinal cord and brain. This association is to a certain extent arbitrary, since the efferent fibers that make up the peripheral nerves are processes of neurons whose bodies are located in the nuclei of the spinal cord and brain. From a functional point of view, the peripheral part of the nervous system consists of conductors connecting nerve centers with receptors and working organs. The anatomy of peripheral nerves is of great importance for the clinic, as the basis for the diagnosis and treatment of diseases and injuries of this part of the nervous system.

Peripheral nerves consist of fibers that have different structures and are not the same functionally. Depending on the presence or absence of the myelin sheath, fibers are myelinated (pulpless) or non-myelinated (pulpless). Based on their diameter, myelinated nerve fibers are divided into thin (1-4 µm), medium (4-8 µm) and thick (more than 8 µm). There is a direct relationship between fiber thickness and the speed of nerve impulses. In thick myelinated fibers, the speed of nerve impulse conduction is approximately 80-120 m/s, in medium ones - 30-80 m/s, in thin ones - 10-30 m/s. Thick myelinated fibers are predominantly motor and conductors of proprioceptive sensitivity, medium-sized fibers conduct impulses of tactile and temperature sensitivity, and thin fibers conduct impulses of pain. Unmyelinated fibers have a small diameter - 1-4 µm and conduct impulses at a speed of 1-2 m/s. They are efferent fibers of the autonomic nervous system.

Nerve fibers in the nerve trunk have a zigzag (sinusoidal) course, which protects them from overstretching and creates an elongation reserve of 12-15% of their original length at a young age and 7-8% at an old age.

Brachial plexus, plexus brachialis, formed by the anterior branches of the four lower cervical, part of the anterior branch of the IV cervical and I thoracic spinal nerves. In the interstitial space, the anterior branches form three trunks: the upper trunk, truncus superior middle trunk, truncus medius, and the lower trunk truncus inferior. These trunks emerge from the interscalene space into the greater supraclavicular fossa and stand out here together with the branches extending from them as the supraclavicular part, pars supraclavicularis, brachial plexus.

The branches extending from the brachial plexus are divided into short and long. Short branches arise mainly from the trunks of the supraclavicular part of the plexus and innervate the bones and soft fabrics shoulder girdle.

1. Dorsal nerve of the scapula, n. dorsdlis scapulae, starts from the anterior branch of the V cervical nerve, lies on the anterior surface of the levator scapulae muscle. Then between this muscle and the posterior scalene muscle, the dorsal scapular nerve travels back along with the descending branch of the transverse cervical artery and branches into the levator scapulae and rhomboid muscles.

2. Long thoracic nerve, n. thordcicus longus, originates from the anterior branches of the V and VI cervical nerves, descends behind the brachial plexus, lies on the lateral surface of the anterior serratus muscle between the lateral thoracic artery in front and the thoracodorsal artery behind, innervates the serratus anterior muscle.

3. Subclavian nerve, n. subcldvius, is heading the shortest route to the subclavian muscle in front of the subclavian artery.

4. Suprascapular nerve, n. suprascapuldris, goes laterally and backwards. Together with the suprascapular artery, it passes through the notch of the scapula under its superior transverse ligament into the supraspinous fossa, and then under the acromion into the infraspinatus fossa. Innervates the supra- and infraspinatus muscles, the capsule of the shoulder joint.

5. Subscapular nerve, n. subscapuldris runs along the anterior surface of the subscapularis muscle, innervates this and the teres major muscles.

6. Thoracospinal nerve, n. thoracodorsails, along the lateral edge of the scapula descends to latissimus muscle the back, which it innervates.

7. Lateral and medial thoracic nerves, pp. pectordles lateralis et medidlls, start from the lateral and medial bundles of the brachial plexus, go forward, pierce the clavipectoral fascia and end in the major (medial nerve) and minor (lateral nerve) pectoral muscles,

8. Axillary nerve, n. axilldris, starts from the posterior bundle of the brachial plexus. Along the anterior surface of the subscapularis muscle it goes down and laterally, then turns back and, together with the posterior circumflex humeral artery, passes through the quadrilateral foramen. After wrapping around the surgical neck of the humerus from behind, the nerve lies under the deltoid muscle. The axillary nerve innervates the deltoid and teres minor muscles, capsule shoulder joint. Terminal branch of the axillary nerve - superior lateral cutaneous nerve of the shoulder, n. cutaneus brdchii lateralis superior, goes around the back edge deltoid muscle and innervates the skin covering the posterior surface of this muscle and the skin of the upper part of the posterolateral region of the shoulder.

19. Lumbar and sacral peripheral nerve plexuses: formation, areas of innervation.

The lumbar plexus is formed by the anterior branches of the three upper lumbar nerves and branches from the IV lumbar and XII thoracic nerves and lies deep in the psoas muscle. The short nerves of the plexus innervate the iliopsoas muscle and the quadratus lumborum muscle. Long nerves(except for the obturator) come out from under the outer edge of the psoas muscle. The upper two innervate bottom part the anterior wall of the abdomen, as well as the skin of the external genitalia. The remaining long nerves are represented by the lateral cutaneous nerve hip, femoral and obturator nerves.

The lateral cutaneous nerve of the thigh, piercing the abdominal wall, exits onto the thigh at the level of the anterior superior iliac spine. Here this nerve innervates the skin of the lateral aspect of the thigh. The femoral nerve is the thickest in lumbar plexus. Coming out onto the thigh under the inguinal ligament (together with the iliopsoas muscle), it immediately breaks down into terminal muscle and cutaneous branches. The muscular branches innervate the sartorius muscle and all the heads of the quadriceps, and the cutaneous branches innervate the skin of the anterior surface of the thigh. The longest cutaneous branch, the hidden nerve, accompanies the large hidden vein, innervating the skin of the medial surface of the leg and foot. The obturator nerve is directed to the small pelvis, along the wall of which it reaches obturator foramen and through it exits to the medial side of the thigh. It innervates the skin of the medial thigh, hip joint and all adductor muscles.

The sacral plexus is formed by the anterior branches of the V lumbar, three sacral nerves and branches from the IV lumbar nerve. In the pelvis, the sacral plexus folds into powerful loops on the surface of the piriformis muscle. The short and long nerves begin from the plexus. Short nerves branch in the hip rotator muscles, in gluteal muscles, the tensor fascia lata muscle, in the skin and muscles of the perineum and in the skin of the external genitalia. The long nerves are the sciatic and posterior cutaneous nerves of the thigh. The posterior cutaneous nerve of the thigh, leaving the pelvis through the greater sciatic foramen, supplies its branches to the skin of the posterior surface of the thigh and popliteal region. The sciatic nerve, consisting of all the anterior branches of the sacral plexus, is the largest in humans. It leaves the pelvis together with the posterior cutaneous nerve of the thigh and gives branches mainly to the muscles of the posterior group of the thigh. Before reaching the popliteal fossa, the sciatic nerve is divided into the tibial (thick) and common peroneal nerves.

The tibial nerve in the lower leg penetrates between the superficial and deep layers flexors, innervating them and knee-joint; here it gives off the long medial cutaneous nerve of the leg. The latter, connected to the lateral cutaneous nerve of the leg by a branch of the common peroneal nerve, innervates the skin of the back of the leg (sural nerve). Having circled behind the medial malleolus, the tibial nerve enters the sole and innervates ankle joint, all the muscles of the foot, the skin of the sole and toes. The common peroneal nerve bends around the popliteal fossa on the lateral side and at the level of the head fibula divided into superficial and deep peroneal nerves. The superficial peroneal nerve innervates the peroneal muscles, as well as the skin of the foot and toes. The deep peroneal nerve supplies the anterior group of muscles of the leg.

20. I.P. Pavlov’s teaching on analyzers. Organ of vision: structure of the membranes of the eyeball, auxiliary apparatus of the eye. Diagram of a visual analyzer.

Nerve plexuses- These are pairs of nerves connected to each other. They extend from the human spine and serve certain areas of his body.

The functions of the nerve plexuses are determined by their localization in one of the parts of the spine, in particular, the cervical, thoracic, as well as lumbar and sacral. These elements can serve muscle movements or be responsible for skin sensitivity; in any case, their diseases lead to disturbances in the areas they serve.

General information

Nerve plexuses are complex connections. They can be internal or external. Internal ones can relate to both the nervous system and the nervous system. External ones are located exclusively in the periphery.

In particular, the nerve plexuses are located in spinal cord.

A total of 31 pairs of nerves pass through the spinal cord.

They exit through the intervertebral foramina, both anterior and posterior. The roots of these nerves intertwine, resulting in the formation of nerve plexuses.

Functions of plexuses

Nerve plexuses generally perform two types of functions. They can be associated with both muscles (motor function) and skin (sensory function). By innervating the skin, the plexuses make it sensitive. Thus, they contribute to the implementation of the tactile function of the skin. With their help, a person feels warmth and cold, distinguishes the textures of the surfaces he feels. A person can also experience pain.

By innervating muscles, nerve plexuses encourage them to move, help a person maintain orientation in space and support the functioning of the vestibular apparatus.

Another function of nerve endings is trophic innervation, which consists of promoting metabolism in the tissues to which they are connected.

Cervical region

The nerve plexus, located in the cervical region of the spine, is formed by anterior branches that belong to the four spinal nerves located superiorly. Their connection occurs through three arched loops.

In the cervical region there are nerves of the two named types, as well as the phrenic one. Thus, the motor plexuses belonging to this area are responsible for the innervation of muscles located nearby. Specifically, these nerves travel to the muscles that serve the head and neck, including the longus muscles and the lemniscus. They also work on the muscles that control the scapula.

The sensory nerves in this area form the transverse nerve, located in the neck, as well as a number of others, including the supraclavicular and lesser occipital.

The phrenic nerve runs inferiorly along the anterior scalene muscle. It enters the sternum through the superior aperture. The latter is located between the subclavian artery and vein

Lumbar region

The lumbar plexus functions together with the sacral plexus. It is responsible for the innervation of the legs, including their muscles, and buttocks.

Chest area

There are 12 pairs of nerves in the chest area. The location for them is the space between the ribs. Their purpose is to innervate the muscles of the abdominal wall, as well as the skin of the chest. These pairs of plexuses do not form.

How many pairs and how are they formed?

In total, there are 31 pairs of nerves in the human body, which means that there are 62 of these elements in the body. This number includes eight pairs cervical nerves, twelve thoracic and five located in the lumbar and sacral region. In addition, there is one plexus in the coccyx region.

The structure of the nerve is determined by the location of the root to which it belongs and its functional characteristics. The anterior branches consist of axons that belong to motor neurons. As a result, they are responsible for muscle movement.

The dorsal roots consist of central processes related to sensory cells, which are connected in a sequential manner with the sensory nuclei and dorsal horns related to the spinal cord.

The nerve fibers originating in the spinal cord are processes of neurons that have a cubic or prismatic shape. This configuration helps to accelerate the transition of pulses along them.

Nerve plexus diseases

Diseases of the spinal nerves affect the main functions of the body, including reflex and motor, as well as sympathetic. It is possible to determine which nerves suffer from inflammation by determining in which areas the innervation is impaired.

In particular, disturbances in the activity of the brachial plexus can be expressed in a number of consequences related to the functioning of the neck. In addition, the patient's fingers become numb. In the future, this can lead to weakening of the forelimbs as a whole. As a result, a person will be unable to hold them in weight or even lift them.

If disturbances appear in the meningeal branch, then the patient suffers from neurological disorders. In particular, his mandibular and trigeminal nerves become inflamed.

With inflammation of the nerves in the chest area, the patient suffers from neuralgia with intercostal localization. He experiences shortness of breath and pain syndrome, the causes of which he often sees in heart disease. However, their real source is precisely the problem with the nerves in this department.

Diseases of the sacral plexus will result in disturbances in the activity of organs localized in the pelvis. There may be numbness of the skin in this area. In serious cases, we can talk about paralysis lower limbs. A person may also suffer from dysfunction of the reproductive system; in particular, problems with sciatic nerve. In addition, pinching it can cause difficulty urinating and defecating, as well as pelvic pain.