Shoulder plexus. Long thoracic nerve treatment What innervates the long thoracic nerve

BRANCHES OF THE SUPRACLUSIC PART OF THE BRACHERIC PLEXUS; AREAS OF INNERVATION. The brachial plexus, plexus brachialis, is formed by the anterior branches of the four lower cervical, part of the anterior branches of the IV cervical and I thoracic spinal nerves. In the interstitial space, the anterior branches form three trunks: the upper trunk, truncus superior, the middle trunk, truncus medius, and the lower trunk, truncus inferior. These trunks from the interstitial space go into a large supraclavicular fossa and stand out here, together with the branches extending from them, as the supraclavicular part, pars supraclavicularis, of the brachial plexus.

Branches extending from the brachial plexus are divided into short and long. Short branches depart mainly from the trunks of the supraclavicular part of the plexus and innervate the bones and soft tissues 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 muscle that lifts the scapula. Then, between this muscle and the posterior scalene muscle, the dorsal nerve of the scapula is sent back along with the descending branch of the transverse artery of the neck and branches in the levator scapula muscle and the rhomboid muscle. 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 thoracic artery behind, innervates the anterior serratus muscle. 3. Subclavian nerve, n. subcldvius, is sent by the shortest path to the subclavian muscle in front of the subclavian artery. 4. Suprascapular nerve, n. suprascapuldris, goes laterally and back. Together with the suprascapular artery, it passes in the notch of the scapula under its upper transverse ligament into the supraspinous fossa, and then under the acromion - into the infraspinatus fossa. Innervates the supraspinatus and infraspinatus muscles, the capsule of the shoulder joint. 5. Subscapular nerve, p. subscapuldris goes along the anterior surface of the subscapularis muscle, innervates this and the large round muscle. 6. Thoracic nerve, n. thoracodorsails, along the lateral edge of the scapula descends to the latissimus dorsi muscle, which it innervates. 7. Lateral and medial pectoral nerves, pp. pectordles lateralis et medidlls, start from the lateral and medial bundles of the brachial plexus, go forward, perforate the clavicular-thoracic fascia and end in the large (medial nerve) and small (lateral nerve) pectoral muscles, 8. Axillary nerve, n. axilldris, starts from the posterior bundle of the brachial plexus. On the anterior surface of the subscapularis muscle, it goes down and laterally, then turns back and, together with the posterior circumflex humerus, passes through the quadrilateral opening. Rounding the surgical neck humerus behind, the nerve lies under the deltoid muscle. The axillary nerve innervates the deltoid and teres minor muscles, the capsule of the shoulder joint. The final branch of the axillary nerve - the upper lateral cutaneous nerve of the shoulder, n. cutaneus brdchii lateralis superior, goes around the posterior edge of the deltoid muscle and innervates the skin covering the posterior surface of this muscle and the skin of the upper posterolateral region of the shoulder. BRANCHES OF THE SUBCLAVIAN PART OF THE BRACHERIC PLEXUS; AREAS OF INNERVATION. Long branches of the brachial plexus depart from the lateral, medial and posterior bundles of the subclavian part of the brachial plexus. The lateral thoracic and musculocutaneous nerves, as well as the lateral root of the median nerve, originate from the lateral bundle. The medial thoracic nerve, medial, cutaneous nerves of the shoulder and forearm, ulnar nerve and medial root of the median nerve begin from the medial bundle. The axillary and radial nerves originate from the posterior bundle. 1. The musculocutaneous nerve, p. musculocutdneus, begins at armpit behind the pectoralis minor. The nerve goes laterally and downwards, pierces the brachiocatorial muscle. Having passed through the abdomen of this muscle in an oblique direction, the musculocutaneous nerve is then located between the posterior surface of the biceps brachii and the anterior surface of the brachialis muscle and exits into the lateral ulnar groove. Having provided these three muscles with muscular branches, rr. musculares, as well as the capsule of the elbow joint, the musculocutaneous nerve in the lower part of the shoulder pierces the fascia and descends onto the forearm as the lateral cutaneous nerve of the forearm, n. cutaneus antebrachii laterals. The terminal branches of this nerve are distributed in the skin of the anterolateral surface of the forearm up to the elevation of the thumb. 2. The median nerve, n. medianus, does not give branches on the shoulder. On the forearm, it innervates with its muscular branches, rr. musculares, a number of muscles: round and square pronators, superficial flexor of the fingers, long flexor of the thumb, long palmar muscle, radial flexor of the wrist, deep flexor of the fingers, i.e. all muscles of the anterior surface of the forearm, except for the ulnar flexor of the hand and the medial part of the deep flexor fingers. The largest branch is the anterior interosseous nerve, p. interosseus anterior innervates the deep muscles of the anterior surface of the forearm and gives the branch to the front wrist joint. The terminal branches of the median nerve are the three common palmar digital nerves, n. digitales palmares communes.

3. The ulnar nerve does not give branches on the shoulder. On the forearm, the ulnar nerve innervates the ulnar flexor of the hand and the medial part of the deep flexor of the fingers, giving them muscle branches, rr. musculdres, as well as the elbow joint. The dorsal branch of the ulnar nerve goes to the back of the forearm between the ulnar flexor of the hand and the ulna.

4. The medial cutaneous nerve of the shoulder, n. cutaneus brachii medidlis, starts from the medial bundle of the brachial plexus, accompanies the brachial artery. Two - three branches perforate the axillary fascia and fascia of the shoulder and innervates the skin of the medial surface of the shoulder.

5. The medial cutaneous nerve of the forearm, n. cutaneus antebrachii medidlis, emerges from the axillary fossa, adjacent to the brachial artery. Innervates the skin of the anteromedial surface of the forearm. 6. Radial nerve, n. radialis starts from the posterior bundle of the brachial plexus at the level of the lower edge of the pectoralis minor muscle between the axillary artery and the subscapularis muscle. Together with the deep artery of the shoulder, the radial nerve passes through the so-called brachial canal, goes around the humerus and leaves the canal in the lower third of the shoulder on its lateral side. Further, the nerve pierces the lateral intermuscular septum of the shoulder and goes down between the brachialis muscle and the beginning of the brachioradialis muscle. At the level of the elbow joint, the radial nerve divides into superficial and deep branches. r. profundus. The superficial branch, r. superficiales, innervates the palmar digital nerves of the median nerve.

On the shoulder, the radial nerve innervates the muscles of the posterior group of the shoulder ( triceps shoulder and ulnar muscle) and the bag of the shoulder joint.

In the brachial canal, the posterior cutaneous nerve of the forearm departs from the radial nerve, p.

Medial bundle, fasciculus medialis , is formed by the anterior branches of the eighth cervical and first thoracic nerves (CVIII - ThI).

It gives off the lateral thoracic nerve, medial thoracic nerve, ulnar nerve, medial cutaneous nerve of the shoulder, medial cutaneous nerve of the forearm, medial root of the median nerve.

1. Lateral thoracic nerve, n. pectoralis lateralis(CV - CVIII, ThI), departs from the upper trunk or slightly lower - from the lateral bundle of the plexus and, heading downward, passes in front of the axillary artery, gives off branches to the deep part of the pectoralis major muscle, often sending a connecting branch to the nerve innervating the pectoralis minor muscle .

2.Medial thoracic nerve, n. pectoralis medialis(CV - CVIII), departs from the lower trunk or lower - from the medial bundle of the plexus and, following downward, passes between the axillary artery and vein, giving the final branches to the pectoralis major and minor muscles.

3. Ulnar nerve, n. ulnaris(Cvii - СVIII), located initially medially from the axillary and the beginning of the brachial arteries; at the level of the middle third of the shoulder, it departs from the brachial artery to the medial periphery of the shoulder towards the medial intermuscular septum of the shoulder, often going in its thickness, and in the lower half of the shoulder lies behind it.

Here, the ulnar nerve, accompanied by the superior ulnar collateral artery, follows, located on medial head the triceps muscle of the shoulder, down into the groove between the medial epicondyle of the humerus and the olecranon, where it lies directly on the bone in the groove of the ulnar nerve and is covered only by fascia and skin. In this area, the nerve gives off a thin articular branch to the capsule of the elbow joint.

Coming out of this gap, the trunk of the ulnar nerve passes between the heads of the ulnar flexor of the wrist, lies on the front surface of the forearm between the deep flexor of the fingers and the ulnar flexor of the wrist, medially from the ulnar arteries and veins. In the lower part of the forearm, the tendon of the ulnar flexor of the wrist covers it along with the vessels.

The ulnar nerve does not give off branches on the shoulder. In the region of the forearm there is a connecting branch between it and the median nerve.

At the border of the middle and lower thirds of the forearm, sometimes higher or lower, the trunk of the ulnar nerve divides into its terminal branches: a thinner dorsal branch of the ulnar nerve and a thicker palmar branch of the ulnar nerve.

Branches of the ulnar nerve:

1) muscle branches, rr. musculares, to the muscles: the ulnar flexor of the wrist and the ulnar part of the deep flexor of the fingers (to the ring finger and little finger); in the thickness of the muscle, the branches of the ulnar nerve are connected to the branch of the median nerve, which innervates the rest of the muscle;

2) dorsal branch of the ulnar nerve, r. dorsalis n. ulnaris, passes between the ulna, closer to its head, and the tendon of the ulnar flexor of the wrist, follows to the back surface of the hand, where, perforating the fascia, it splits into branches to the skin of the ulnar side of the back of the hand and the backs of the fingers, giving off the dorsal digital nerves:

a) dorsal digital nerves, nn. digitales dorsales, in the amount of five, innervate the skin of the back surface of the little finger, ring and ulnar sides of the middle fingers. On the little finger, the nerves reach the base of the nail, and on the ring and middle fingers they spread only within the skin of the proximal phalanx;

b) connecting branches (non-permanent) with the superficial branch of the radial nerve and with the branches of the medial, dorsal and lateral cutaneous nerves of the forearm;

c) palmar branch of the ulnar nerve, r. palmaris n. ulnaris, is accompanied by the ulnar artery and is a continuation of the main trunk of the ulnar nerve. In the distal forearm, a small palmar cutaneous branch departs from it, sometimes in the form of two thin nerves.

It sends a branch to the ulnar artery and, piercing the fascia of the forearm, between the ulnar flexor of the wrist and the superficial flexor of the fingers, it goes to the skin of the ulnar edge of the area of ​​the wrist joint, to the skin of the little finger elevation and to the skin of the little finger. There is a connecting branch between this branch and the medial cutaneous nerve of the forearm.

From the superficial branch, r. superficialis, depart:

a) common palmar digital nerve, n. digitalis palmaris communis, lies under the palmar aponeurosis along the fourth interosseous space. Here it divides into its own palmar digital nerves, nn. digitales palmares proprii, which include two branches: own palmar digital nerve of the little finger (innervates the skin of the radial side of the little finger) and own palmar digital nerve of the ring finger (innervates the skin of the ulnar surface of the ring finger and the skin of the back surface of the middle and distal phalanges of the same finger);

b) skin branches pierce the thickness of the short palmar muscle and innervate the skin of the area of ​​​​the elevation of the little finger;

c) connecting branch with the third common palmar digital nerve from the median nerve;

d) own palmar digital nerve, n. digitalis palmaris proprius, located at the ulnar edge of the palmar aponeurosis along the muscles of the little finger elevation, passes to the palmar surface of the little finger, innervating the skin of its ulnar edge;

Areas of distribution of cutaneous nerves of the girdle and free part upper limb, right (semi-schematically).

e) muscular branch - one or more thin nerves to the short palmar muscle (sometimes to other muscles of the little finger elevation).

The terminal branches of the cutaneous nerves of the fingers ends with lamellar bodies, corpuscula lamellosa, encapsulated receptors.

Deep branch, r. profundus, begins at the radial surface of the pisiform bone. This branch passes through the proximal parts of the muscles that form the elevation of the little finger, between the short flexor and the abductor muscle of the little finger, and, perforating the muscle that opposes the little finger, penetrates, accompanied by the deep branch of the ulnar artery, into the deep space of the palm between the tendons of the long flexors and the interosseous muscles. It runs in a slightly arcuate manner, almost along the course of the deep palmar arterial arch towards the thumb.

The deep branch sends the following nerves:

a) connecting branches with the first common palmar digital nerve of the median nerve;

b) articular branches to the articular capsules and periosteum of the bones of the hand;

c) muscular branches, rr. musculares, which go to the muscles of the eminence of the thumb; little finger elevations (m. abductor digiti minimi, m. flexor digiti minimi brevis, m. opponens digiti minimi); middle group of muscles of the hand (mm. lumbricales III, IV, mm. interossei palmares et dorsales);

d) the perforating branches penetrate through the interosseous spaces to the dorsal surface of the hand, where they connect with the branches of the interosseous dorsal nerve of the forearm.

4.Medial cutaneous nerve of the shoulder, n. cutaneus brachii medialis(СVIII, ThI, sometimes ThII, ThIII), originates from the medial bundle of the brachial plexus and is located in the axillary cavity anterior to the subscapularis and latissimus dorsi, first in front of the axillary artery, and then lies medially to it.

Here the nerve joins with the lateral cutaneous branch of the second thoracic nerve, sometimes the third thoracic nerve (ThIII), which are called the intercostal-brachial nerves, nn. intercostobrachiales. Two, sometimes three small nerve trunks pierce the axillary and brachial fascia and branch out in the skin of the axillary cavity, the anterior and postero-medial surfaces of the shoulder to the medial epicondyle of the humerus and the olecranon.

5. Medial cutaneous nerve of the forearm, n. Cutaneus antebrachii medialis(СVIII, ThI), lies in the axillary cavity along with the axillary artery, and in the shoulder region - with the brachial artery and median nerve. Having reached the middle of the shoulder, it passes through the fascia in the place where the medial saphenous vein of the upper limb penetrates through it, and, having entered the subcutaneous layer (sometimes more proximal), is divided into the anterior branch and the ulnar branch:

1) anterior branch, r. anterior, located in front of the aponeurosis of the biceps of the shoulder, on the radial side of the medial saphenous vein, then lies behind the intermediate vein of the elbow and branches in the skin of the ulnar half palmar surface forearms to the area of ​​the wrist joint.
In its course, the anterior branch connects with the branches of the lateral cutaneous nerve of the forearm (from the musculocutaneous nerve);

2) ulnar branch, r. ulnaris, is located on the ulnar side of the medial saphenous vein of the arm, descends along the ulnar edge of the forearm and, passing with its branches to its back surface, reaches the area of ​​the wrist joint.
In its course, the ulnar branch connects with the branches of the posterior cutaneous nerve of the forearm (from the radial nerve) and with the branches of the dorsal branch of the ulnar nerve.

6. C median nerve, n. medianus(CVI - ThI), is formed by the lateral root extending from the lateral bundle, and the medial root extending from the medial bundle. Both roots, connecting at an acute angle, form a loop, which is located on the anterior surface of the axillary artery.

Following further in one trunk, the median nerve is adjacent to the radial side of the brachial artery and, together with it, is located under the fascia of the shoulder in the medial groove of the shoulder. Having reached the middle of the shoulder, the nerve crosses the artery in front, is located on its ulnar side and gives 2-3 branches to the capsule of the elbow joint.

Continuing its course, it, together with the brachial artery, passes in the cubital fossa under the aponeurosis of the biceps brachii muscle on the forearm. Here the median nerve accompanies the ulnar artery at some distance, which is located behind the nerve.

Penetrating further between both heads of the round pronator, the median nerve goes to the midline of the forearm, fits under the tendon of the superficial flexor of the fingers and, accompanied by the median artery, follows between the superficial and deep flexors of the fingers to the area of ​​the wrist joint.

Between the tendons of the radial flexor of the wrist and the long palmar muscle, the median nerve, together with the tendons of both finger flexors, passes under the flexor retinaculum in the carpal tunnel to the hand, where it divides into its terminal branches.

In the region of the hand under the palmar aponeurosis, the terminal branches of the median nerve are located between the superficial palmar arch of the ulnar artery and the tendons of the superficial flexor of the fingers, giving a number of articular branches to the capsules of the wrist joints and joints I-III (IV) of the fingers from the side of the palmar surface.

Branches of the median nerve:

1) anterior interosseous nerve (forearm), n. interosseus (antebrachii) anterior, originates from the main trunk of the median nerve at the level of the round pronator and, following distally, accompanied by the anterior interosseous artery, is located between the long flexor of the thumb and the deep flexor of the fingers, reaching the square pronator.

It innervates the long flexor of the thumb, the deep flexor of the fingers (the radial part to the index and middle fingers) and the square pronator;

2) connecting branches with the ulnar nerve, rr. communicantes cum nervo ulnari, in the thickness of the deep flexor of the fingers.

In addition, a number of connecting branches are described:

a) in the shoulder area with a musculocutaneous nerve (sometimes 2-3), unstable, located in the upper third of the shoulder;

b) in the area of ​​the hand with the superficial branch of the ulnar nerve and with the superficial branch of the radial nerve;

3) muscle branches, rr. musculares.

In the shoulder region, the median nerve does not give off branches (except for the indicated connecting branch with the musculocutaneous nerve). In the region of the forearm, muscle branches depart from the main trunk of the median nerve at the level of the medial epicondyle of the humerus and go to the pronator teres, radial flexor of the wrist, long palmar muscle and to the superficial flexor of the fingers;

4) palmar branch of the median nerve, r. palmaris n. mediani, - a thin branch (sometimes two), departs from the main trunk of the median nerve in the region of the lower third of the forearm between the tendons of the radial flexor of the wrist and the long palmar muscle, pierces the fascia of the forearm and branches in the skin of the palmar surface of the wrist joint, thumb and palm;

5) common palmar digital nerves I, II, III, nn. digit ales palmares communes I, II, III, are formed by branching of the main trunk of the median nerve. They depart at the level of the distal edge of the flexor retinaculum, are located under the palmar aponeurosis and the superficial palmar arch in the first, second and third interosseous spaces, sending thin skin branches that penetrate through the palmar aponeurosis into the skin of the palm, in the region of its middle sections.

Muscle branches depart from each common palmar digital nerve and innervate the following muscles of the palm area:

a) the first common palmar digital nerve - m. abductor pollicis brevis, m. flexor pollicis brevis (caput superficiale), m. opponens pollicis, m. lumbricalis I;

6) the second common palmar digital nerve - m. lumbricalis II;

c) the third common palmar digital nerve - m. lumbricalis III (variably).

Then the common palmar digital nerves give off their own palmar digital nerves, nn. digitales palmares proprii, which innervate the skin of the radial and ulnar edges of the palmar surface of the thumb, index, middle fingers and the skin of the radial edge of the same surface of the ring finger. The first common palmar digital nerve sends 3 nerves: two to the thumb and one to the index finger, the second - two: to the index and middle fingers, and the third - two: to the middle and ring fingers.

Own palmar digital nerves of the thumb innervate the skin of the radial and ulnar edges of the palmar surface of the thumb and send connecting branches to the superficial branch of the radial nerve.

Own digital nerves, innervating the skin of the index, middle and ring fingers, send branches to the skin of the dorsal surface of the middle and distal phalanges of the same fingers.

The somatic peripheral nervous system includes the roots of the spinal nerves, spinal nodes, nerve plexuses, spinal and cranial nerves. Even within the spinal canal, the anterior (motor) and posterior (sensory) roots gradually approach each other, then merge and form the radicular nerve up to the spinal nodes, after which the spinal nerve. Therefore, the spinal nerves are mixed, as they contain motor (efferent) fibers from the cells of the anterior horns, sensory (afferent) fibers from the cells of the spinal nodes, and autonomic fibers from the cells of the lateral horns and nodes of the sympathetic trunk.

After leaving the central canal through the intervertebral foramina, the spinal nerves divide into anterior branches ( rr. anteriores), innervating the skin, muscles of the limbs and the anterior surface of the body; back branches ( rr. posteriores), innervating the skin and muscles of the back surface of the body; meningeal branches ( rr. meningei), heading to the hard shell of the spinal cord, and connecting branches ( rr. communicantes), containing sympathetic preganglionic fibers following to the nodes of the sympathetic trunk ( gangl. trunci sympathici). The anterior branches of the cervical, lumbar and sacral spinal nerves form bundles of the corresponding plexuses, from which the peripheral nerves depart.

Nerve fiber (axon) is the main structural element of the peripheral nerve. Distinguish between myelinated and non-myelinated nerve fibers. Myelinated nerve fibers are divided into thick, which conduct impulses at a speed of 40–70 m/s, and thin, conducting pulses with a speed of 10–20 m/s. The speed of impulse conduction along unmyelinated nerve fibers is 0.7–1.5 m/s. Thick myelin sheath fibers provide complex and deep species sensitivity (two-dimensional-spatial feeling, discriminatory feeling, stereognosis, joint-muscular feeling, etc.), fibers with a thin myelin sheath - pain, temperature and tactile, and non-myelinated fibers - only pain sensitivity. At the same time, fibers with a thin myelin sheath are involved in the formation of a sensation of localized pain, and non-myelinated fibers are involved in diffuse pain. Myelinated axons predominate in the somatic (spinal and cranial) nerves, unmyelinated - in the visceral nerves of the sympathetic part of the autonomic nervous system; the nerves of its parasympathetic part (vagus, oculomotor nerve root, etc.) mainly consist of myelin nerve fibers.

Nerve fibers are grouped into separate bundles of various calibers, delimited from other formations of the nerve trunk by the perineural sheath. On a transverse section of human nerves, connective tissue sheaths (epineurium, perineurium) occupy much more space (67–84%) than bundles of nerve fibers. The bundles in the nerve trunks can be located relatively rarely, with intervals of 170-250 microns, and more often - the distance between the bundles is less than 85-170 microns.

The epineurium of nerves with a large number of bundles is replete with small-caliber blood vessels. In nerves with a small number of bundles, the vessels are single, but larger. The thickness of the bundles depends not only on the number, but also on the type of their constituent nerve fibers. More powerful bundles are formed by myelin fibers. Due to the fact that the nerve fibers pass from one bundle to another, complex intrastem plexuses are formed. This partly explains the absence of clear zones of impaired motor, sensory and autonomic functions in case of partial nerve damage.

cervical plexus (plexus cervicalis) (Fig. 24). The plexus is formed by the anterior branches of the four upper cervical spinal nerves (C 1 -C 4) and is located lateral to the transverse processes on the anterior surface of the middle scalene muscle and the muscle that lifts the scapula, under the sternocleidomastoid muscle. From it leave the skin and muscle branches to deep muscles neck, which are involved in the innervation of the scalp, ear, neck, diaphragm and shoulder girdle. With the defeat, pain and sensitivity disorders occur in the zone of innervation.

The cervical plexus forms the following nerves.

Lesser occipital nerve (n. occipitalis minor) is formed from the anterior branches of the C 1 -C 3 cervical spinal nerves. It innervates the skin of the lateral part of the occipital region and partially the auricle. When the nerve is irritated, occipital neuralgia occurs, and with compression-ischemic lesions - paresthesia in the external occipital region.

Rice. 24. cervical plexus:

1 - suboccipital nerve; 2 - large occipital nerve; 3 - small occipital nerve; 4 - a large ear nerve; 5 - transverse nerve of the neck; 6 - supraclavicular nerves; 7 - phrenic nerve; 8 - neck loop; 9 - upper cervical node; 10 - hypoglossal nerve

Great ear nerve (n. auricularis magnus) is formed from the anterior branches of the C 3 -C 4 cervical spinal nerves and provides innervation to the earlobe, auricle and external auditory canal.

Transverse nerve of the neck (n. transverse colli) is formed from the anterior branches of the C 2 -C 3 cervical spinal nerves and innervates the skin of the lateral and anterior regions of the neck.

Supraclavicular nerves (nn. supraclavicularis) are formed from the fibers of the anterior branches of the C 3 -C 4 cervical spinal nerves and innervate the skin of the supraclavicular, subclavian, suprascapular regions and the upper outer part of the shoulder.

The defeat of the supraclavicular nerves is accompanied by pain in the zone of innervation, aggravated by tilting the head to the side. Intense pain is accompanied, as a rule, by tonic tension of the occipital muscles, leading to a forced position of the head (in such cases, differential diagnosis with meningeal syndrome is necessary). In addition, there are disorders of surface sensitivity in the zone of innervation and pain points along the posterior edge of the sternocleidomastoid muscle.

Phrenic nerve (n. phrenicus) is formed from C 3 -C 5 cervical spinal nerves, is mixed. It innervates the diaphragm, pleura, pericardium, peritoneum and ligaments of the liver. When the nerve is damaged, paralysis of the same half of the diaphragm occurs (it manifests itself in paradoxical breathing: when inhaling, the epigastric region sinks, when exhaling, it protrudes), and when irritated, hiccups, shortness of breath and pain in the hypochondrium, shoulder girdle and neck can be observed. Most often, the nerve is affected in infectious diseases (diphtheria, influenza, scarlet fever, etc.), intoxication, tumor metastases in the cervical vertebrae, etc.

Brachial plexus (plexus brachialis) (see fig. 25 on color incl.). The plexus is formed by the connection of the anterior branches of the four lower cervical (C 5 -C 8) and two upper thoracic (Th 1 -Th 2) spinal nerves. Nerve fibers form primary bundles - upper, middle and lower, and then secondary bundles (lateral, medial and posterior). The upper bundle is formed from the fusion of the anterior branches of the C 5 -C 6 spinal nerves, the middle one - C 7 and the lower one - C 8 -Th 2. In the brachial plexus, the supraclavicular and subclavian parts are distinguished. The supraclavicular part of the brachial plexus is located in the supraclavicular fossa. The following nerves are formed from it.

Anterior pectoral nerves (rr. anteriores nn. thoracici) innervate the pectoral muscles: large (leads and rotates the shoulder inward) and small (pulls the scapula forward and downwards). Isolated lesions of these nerves are rare. Paresis or paralysis of these muscles is manifested by difficulty in bringing the upper limb to the chest.

Dorsal nerve of the scapula (n. dorsalis scapulae) innervates the large and small rhomboid muscles and the muscle that lifts the scapula.

Long thoracic nerve (n. thoracicus longus) innervates the anterior serratus muscle, which brings the scapula closer to the chest.

subclavian nerve (n. subclavius) innervates the subclavian muscle, which pulls the clavicle down and medially.

suprascapular nerve (n. suprascapularis). The sensory part supplies the ligaments and capsule of the shoulder joint, the motor part supplies the supraspinatus and infraspinatus muscles (abduction of the shoulder at an angle of 15° and external rotation of the shoulder) (see color incl., fig. 25).

thoracic nerve (n. thoracodorsalis) innervates latissimus dorsi back. His defeat is accompanied by a violation of the movement of the hand back behind the back and towards the midline, i.e. rotation inward.

Subclavian part of the brachial plexus located in the armpit and innervates the arm. It distinguishes three bundles: lateral, formed by the anterior branches of the C 5 -C 7 nerves; medial - anterior branches of C 8 and Th 1 nerves; posterior - by the posterior branches of the three primary bundles. The musculocutaneous nerve is formed from the lateral bundle ( n. musculocutaneus) and the lateral root of the median nerve ( n. medianus); from the medial - ulnar nerve ( n. ulnaris), medial cutaneous nerve of the shoulder ( n. cutaneus brachii medialis) and forearms ( ), medial root of the median nerve; from the back - the axillary nerve ( n. axillaris) and radial nerve ( n. radialis).

median nerve (n. medianus) contains motor, sensory and a large number of autonomic fibers. Innervates the muscles of the anterior surface of the forearm; flexors of the hand and I-II fingers, pronators of the forearm and hand, muscle opposing the thumb of the hand and I-II worm-like muscles; skin of the palmar surface of the radial edge of the hand, I-III and half of the IV fingers, the back surface of the terminal phalanges of I-II and partially IV fingers. With damage to the median nerve, flexion of the hand and fingers I–III, opposition of the thumb and pronation (grasping objects is difficult), flexion of the proximal phalanges and extension of the remaining phalanges of the II–III fingers are disturbed. The muscles of the forearm and the eminence of the thumb atrophy, the "monkey hand" is formed, the appearance of vegetative-trophic disorders (regional pain syndrome, causalgia) is possible. Deep sensitivity is lost in the terminal interphalangeal joint of the second finger.

The nerve is often damaged in natural anatomical tunnels. At the same time, the syndrome of the supracondylar-ulnar groove is distinguished (it is provoked by extension of the forearm and pronation in combination with forced flexion of the fingers and is accompanied by pain, paresthesia in the zone of innervation of the median nerve, weakness of the flexors of the hand and fingers); pronator teres syndrome (symptoms of loss of function of the median nerve are aggravated by pressure in the area of ​​the pronator teres); carpal tunnel syndrome (the main symptom is paresthesia and pain in the fingers, aggravated by carpal flexion test and tapping along the projection of the median nerve at the level of the wrist).

Ulnar nerve (n. ulnaris) innervates the flexors of the IV and V fingers, all interosseous, III and IV worm-like muscles, the muscle that adducts the first finger of the hand and removes the fifth finger. Provides sensitive innervation to the palmar surface of the V and half of the IV, as well as the back surface of the V, IV and half of the III fingers.

When the nerve is damaged, the flexion of the little finger, the spreading and adduction of the fingers (the patient cannot grasp and hold objects between the fingers), the flexion of the proximal and the extension of the remaining phalanges of the IV-V fingers are upset. There is a partial atrophy of the muscles of the forearm, the interosseous spaces of the hand sink down and the elevation of the little finger is flattened (“clawed paw”). Sensitive disorders extend to the ulnar part of the hand from the palmar and back sides, the region of the V and the ulnar side of the IV fingers. Deep sensitivity is disturbed in the joints of the fifth finger.

There are the following tunnel syndromes of the ulnar nerve: cubital syndrome (with rheumatoid arthritis, prolonged sitting at a desk, paresthesia and numbness first appear in the area of ​​​​innervation of the ulnar nerve, and later weakness and atrophy of the muscles of the hand); wrist syndrome (paresthesia on the inner surface of the hand, weakness of flexion and adduction of the fifth finger, aggravated by finger pressure and tapping on the wrist).

Medial cutaneous nerve of the shoulder (n. cutaneus brachii medialis) innervates the skin of the inner surface of the shoulder. It is affected by prolonged walking on crutches or cicatricial processes in the upper third of the shoulder.

Medial cutaneous nerve of the forearm (n. Cutaneus antebrachii medialis) innervates the skin of the inner surface of the forearm. It is affected during cicatricial processes along the medial surface of the middle and lower third of the shoulder.

Clinical signs of damage to these nerves are paresthesia, pain, numbness in the zone of innervation.

axillary nerve (n. axillaris) innervates the deltoid muscle, which abducts the shoulder to a horizontal level, and also participates in flexion and extension of the shoulder (movement of the shoulder forward and backward), rotation of the shoulder outward (small round muscle) and provides sensitive innervation of the skin in the region of the shoulder joint and the outer surface of the shoulder in its upper third. Nerve damage is manifested by pain in the shoulder joint, impaired abduction of the upper limb to the side, raising it forward and backward, hypotrophy of the deltoid muscle (a differential diagnosis must be made with humeroscapular periarthrosis and cervicothoracic radiculopathy).

radial nerve (n. radialis) innervates the triceps muscle of the shoulder, the extensors of the hand and fingers, the arch support of the forearm, the brachioradialis muscle and the muscle that abducts the first finger of the hand. Provides sensitive innervation of the posterior region of the shoulder and forearm, the radial part of the dorsal surface of I, II and partially III fingers. If the radial nerve is damaged, the extension of the forearm, hand and fingers, and the abduction of the first finger are upset. The triceps muscle of the shoulder is atrophied (“hanging hand”, Fig. 26). The extensor-elbow and carporadial reflexes decrease or disappear, sensitivity in the zone of innervation is upset.

There are lesions of the radial nerve in the armpit (with fractures of the humerus), at the level of the intermuscular septum of the shoulder (“sleep paralysis”), in the area of ​​​​the elbow joint and the upper part of the forearm (lipomas, fibromas of this zone, bursitis, synovitis of the elbow joint, etc.) , supinator syndrome, Turner's syndrome (compression of the radial nerve with a fracture of the lower end of the radius).

Clinical symptoms of lesions of the brachial plexus depends on the location and prevalence of the pathological process. So, when the upper primary bundle is damaged (in case of injuries, prolonged throwing of the hands over the head during the operation, tumor metastases, etc.) Erb-Duchenne superior palsy characterized by damage to the proximal upper limb while maintaining the function of the hand and fingers. The hand hangs like a whip. The reflex from the biceps muscle of the shoulder disappears, and the carporadial reflex decreases. The sensitivity is upset according to the radicular type (C 5 -C 6) on the outer surface of the shoulder and forearm. One of the clinical forms of compression-ischemic lesions of the upper bundle of the brachial plexus is Personage-Turner neuralgic amyotrophy, which begins with increasing pain in the area of ​​the shoulder girdle, shoulder and scapula and gradually turns into deep paresis of the proximal arm with distinct atrophy of the anterior serratus, deltoid and parascapular muscles.

Rice. 26."Dangling brush" with damage to the radial nerve

Damage to the primary inferior plexus bundle causes inferior paralysis of Dejerine-Klumpke, in which distal paralysis occurs with a primary lesion and atrophy of the small muscles and flexors of the fingers and hand. Sometimes, with a high lesion, Horner's syndrome joins. Sensitivity is disturbed by the radicular type (C 8 -Th 2) on the inner surface of the hand, forearm and shoulder.

With a total lesion of the brachial plexus (with gunshot wounds of the supraclavicular and subclavian regions, with a fracture of the clavicle, 1st rib, with a dislocation of the humerus, tumors or metastases of this localization, etc.), peripheral paralysis of the arm and shoulder girdle occurs with sensitivity disorder and pain syndrome in the neck, shoulder blade, arm, with loss of extensor-elbow, flexion-elbow and carporadial reflexes. Most often, the brachial plexus is affected in musculo-tonic syndromes. cervical osteochondrosis(e.g. Naffziger anterior scalene syndrome; scalenus syndrome; pectoralis minor syndrome - Wright-Mendlovich hyperabduction syndrome; Steinbroker's shoulder-hand syndrome; Paget-Schroetter syndrome with subclavian vein thrombosis).

Thoracic nerves (nn. thoracici) are mixed, formed from roots Th 2 -Th 12 . The anterior branches of the thoracic nerves are intercostal. The first six intercostal nerves innervate the muscles and skin of the anterior and lateral sections. chest, six lower - muscles and skin of the anterior abdominal wall. The posterior branches of the thoracic nerves innervate the muscles and skin of the back. With damage to the intercostal nerves, pains of a girdle and constriction character arise and sensitivity is upset in their respective zones, reflexes fall out, muscle paresis develops abdominals. When spinal nodes are involved in the pathological process (ganglioneuritis), a rash in the form of vesicles is observed ( herpes zoster).

Lumbar plexus (plexus lumbalis) (Fig. 27, A) is formed from the anterior branches of the lumbar (L 1 -L 4) spinal nerves and partially the anterior branches of the 12th thoracic nerve. It is located anterior to the transverse processes of the lumbar vertebrae on the anterior surface of the square muscle of the lower back, in the thickness of the psoas major muscle.

The following nerves emerge from the plexus: ilio-hypogastric, ilio-inguinal, femoral-genital, femoral, obturator, lateral cutaneous nerve of the thigh. The defeat of the entire plexus is rare (with fractures of the spine and pelvic bones; with compression by tumors, hematoma, pregnant uterus; with inflammatory processes in the retroperitoneal space), its individual trunks are much more often affected. The clinical picture of lumbar plexopathy is characterized by pain in the lower abdomen, lumbar region, pelvic bones; a decrease in all types of sensitivity of the skin of the pelvic girdle and thighs; movement disorders in lumbar spine, hip and knee joints.

iliohypogastric nerve (n. iliohypogastricus) is formed from the anterior branches of the Th 12 and L 1 spinal nerves. Innervates the transverse, rectus and oblique muscles of the abdomen, the skin of the suprapubic region and the upper lateral region of the thigh. It is usually damaged during operations on the organs of the abdomen or small pelvis (especially during hernia repair).

ilioinguinal nerve (n. ilioinguinalis) is formed from the anterior branch L 1 . Innervates the lower sections of the transverse, internal and external oblique muscles of the abdomen, the skin of the upper section of the inner surface of the thigh, genitals and inguinal region. It is usually damaged during operations for hernia repair, appendectomy, nephrectomy; development of compression-ischemic (tunnel) neuropathy is also possible. Nerve damage is manifested by pain and paresthesia in the groin, antalgic posture when walking and limitation of extension, internal rotation and abduction of the hip.

Genital femoral nerve (n. genitofemoralis) is formed from the anterior branches of the L 1 -L 2 spinal nerves. motor fibers innervate m. cremaster And tunica dartos, sensitive - the skin of the anterior and inner thighs in the upper third. When the nerve is damaged, the cremasteric reflex decreases or disappears and sensitivity disorders (most often pain in the inguinal region) occur in the corresponding zone.

femoral nerve (n. femoralis) is formed from the anterior branches of the L 1 -L 4 spinal nerves. It innervates the iliopsoas muscle (flexes the thigh in the hip joint and the spine in the lumbar region), the quadriceps muscle of the thigh (flexes the thigh and lower leg, turns the bent lower leg inward). Sensory fibers innervate the skin of the lower two-thirds of the anterior surface of the thigh and the anterior inner surface of the lower leg. It is affected by injuries, spontaneous hematomas along its course, inguinal lymphadenitis, appendicular abscess, etc.

Rice. 27. Lumbar- sacral plexus:

A- lumbar plexus: 1 - iliac-hypogastric nerve; 2 - ilioinguinal nerve; 3 - femoral-genital nerve; 4 - lateral cutaneous nerve of the thigh; 5 - obturator nerve; 6 - femoral nerve.

B- sacral plexus: 7 - superior gluteal nerve; 8 - lower gluteal nerve; 9 - sciatic nerve; 10 - common peroneal nerve; 11 - tibial nerve; 12 - posterior cutaneous nerve of the thigh; 13 - pudendal nerve n. pudendum); 14 - coccygeal nerve ( n. coccygeus)

If the nerve is damaged below the inguinal ligament, pain first occurs in the inguinal region, radiating to the lower back and thigh; leg extension is impossible, atrophy of the quadriceps femoris muscle is noticeable, the knee reflex is lost, sensitivity on the anterior inner surface of the leg is impaired. If the nerve is damaged above the inguinal ligament, sensitivity disorders on the anterior surface of the thigh, a violation of hip flexion (bringing it to the stomach) and lifting the body in a supine position join; Difficulty gait (the leg is excessively unbent in knee joint) and especially climbing stairs. When the nerve is irritated, Wasserman's symptom appears: in the position of the patient on the stomach, raising the straightened leg or bending at the knee joint causes pain in the groin or along the front surface of the thigh.

obturator nerve (n. obturatorius) is formed from the anterior branches of the L 4 -L 5 spinal nerves and is located behind or inside the psoas major muscle. Motor fibers innervate the muscles that adduct the thigh. Sensory fibers innervate lower half inner surface of the thigh. Nerve lesions are possible at the beginning of the discharge (with retroperitoneal hematoma).

When the nerve is damaged, it is difficult to adduct the leg, it is impossible to lay one leg on the other, in addition, there are violations of sensitivity in the corresponding zone.

Lateral femoral cutaneous nerve (n. Cutaneus femoris lateralis) is formed from the fibers of the roots L 2 -L 3 and innervates the skin of the outer surface of the thigh. When a nerve is damaged, sensitivity disorders occur in the zone of innervation, with irritation - paresthesia, numbness in the same area of ​​\u200b\u200bthe skin (Bernhardt-Roth disease, or paresthetic meralgia).

sacral plexus (plexus sacralis) (Fig. 27, B). It is formed from the anterior branches of the L 4 -S 3 roots, located on the anterior surface of the sacrum and piriformis muscle. The nerves emanating from it exit through the large sciatic foramen. The sacral plexus is connected to the lumbar plexus by the anterior branch of the S 1 spinal nerve. The defeat of the sacral plexus or its constituent roots causes loss of function of the nerves emerging from it.

superior gluteal nerve (n. gluteus superior) is formed from fibers L 4 , L 5 and S 1 roots. Innervates the gluteus minimus and gluteus medius and the tensor fascia lata, which abduct the thigh outward. With the defeat of this nerve, hip abduction is difficult; bilateral lesion is characterized by a "duck" gait.

Inferior gluteal nerve (n. gluteus inferior) is formed from fibers L 5 , S 1 , S 2 roots and innervates the gluteus maximus muscle and the articular capsule of the hip joint. When the nerve is damaged, the extension (abduction posteriorly) of the thigh and the straightening of the body when standing in a forward-bent position are disturbed.

Posterior femoral cutaneous nerve (n. Cutaneus femoris posterior) is formed from the anterior branches of the S 1 -S 2 roots and innervates the skin of the lower buttocks, scrotum (labia majora), perineum and posterior thigh to the popliteal fossa.

sciatic nerve (n. ischiadicus) is a direct continuation of the anterior branches of the L 4 -S 3 spinal nerves. At the level of the thigh, branches extend from the nerve to the biceps femoris, semimembranosus, and semitendinosus muscles, which flex the lower leg and turn it outward or inward. In the upper part of the popliteal fossa, the sciatic nerve divides into the tibial and common peroneal nerves, although the subepineural isolation of both portions of the nerve is usually carried out in the pelvic cavity.

When the sciatic nerve is damaged above the gluteal fold, there is an inability to flex the lower leg, as well as loss of the function of the peroneal and tibial nerves (paralysis of the foot and fingers, loss of the Achilles reflex and anesthesia of the entire lower leg and foot). In addition, often the defeat of the sciatic nerves is accompanied by severe pain. When the nerve is irritated, the symptom of Lasegue is characteristic: pain along the sciatic nerve when raising the leg straightened at the knee joint in the supine position. When the sciatic nerve is affected below the gluteal fold, as a rule, the peroneal or tibial nerve is predominantly affected.

Common peroneal nerve (n. peroneus communis) is formed from L 4 -S 2 spinal nerves. Its main branches are the superficial peroneal ( n. peroneus superficialis) and deep peroneal nerve ( n. peroneus profundus). Muscular branches of the superficial peroneal nerve innervate the long and short peroneal muscles, raising the outer edge of the foot, as a result of which the foot is pronated and retracted, and the skin branches innervate the dorsum of the foot and the lateral region of the lower leg. When the nerve is damaged, the abduction and elevation of the outer edge of the foot is disturbed, the sensitivity in the corresponding zone is upset.

The muscular branches of the deep peroneal nerve innervate the anterior tibial muscle, the long and short extensors of the toes, which unbend, adduct and supinate the foot, unbend the proximal phalanges of the toes; cutaneous branches - a wedge-shaped area of ​​​​the skin of the rear of the foot between the I and II fingers. Damage to the nerve leads to a violation of the dorsiflexion of the toes, atrophy of the anterior group of muscles of the lower leg, and a disorder of sensitivity in the corresponding zone. Signs of damage to the common peroneal nerve are sagging foot (“horse foot”), inability to extend the foot, “cock” gait (steppage) (Fig. 28), inability to stand and walk on the heels, sensory disturbance on the back of the foot and in the lateral region of the lower leg.

tibial nerve (n. tibialis) is formed from L 4 -S 3 spinal nerves. The muscle branches innervate the triceps muscle of the lower leg (flexes the foot), the posterior tibial muscle (flexes the foot, turns it outward and adducts), the flexor of the toes (flexes the foot and its toes). Sensory branches innervate the posterior region of the lower leg, the sole and plantar surface of the fingers with access to the rear of the distal phalanges and the lateral edge of the foot.

With damage to the tibial nerve, the foot takes on a specific appearance: a protruding heel, a deep arch and a claw-like position of the fingers ( pes calcaneus); impossibility of plantar flexion of the foot and its toes, walking and standing on toes. Reduced sensitivity in the back of the leg, sole, toes, often there are vegetative-trophic disorders, causalgia.

Rice. 28."Cock" gait (steppage) with damage to the peroneal nerve

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The brachial plexus (plexus brachialis) is formed from the anterior branches of the C5 Th1 spinal nerves (Fig. 8.3). The spinal nerves, from which the brachial plexus is formed, leave the spinal canal through the corresponding intervertebral foramens, passing between the anterior and posterior intertransverse muscles. The anterior branches of the spinal nerves, connecting with each other, first form 3 trunks (primary bundles) of the brachial plexus that make it up Fig. 8.3. Shoulder plexus. I - primary upper beam; II - primary middle beam; III - primary lower beam; P - secondary posterior bundle; L - secondary outer beam; M - secondary internal beam; 1 - musculocutaneous nerve; 2 - axillary nerve; 3 - radial nerve; 4 - median nerve; 5 - ulnar nerve; 6 - internal cutaneous nerve; 7 - internal cutaneous nerve of the forearm. supraclavicular part, each of which is connected by means of white connecting branches to the middle or lower cervical vegetative nodes. 1. The superior trunk arises from the connection of the anterior branches of the C5 and C6 spinal nerves. 2. The middle trunk is a continuation of the anterior branch of the C7 spinal nerve. 3. The lower trunk consists of the anterior branches of the C8, Th1 and Th2 spinal nerves. The trunks of the brachial plexus descend between the anterior and middle scalene muscles above and behind the subclavian artery and pass into the subclavian part of the brachial plexus, located in the zone of the subclavian and axillary fossae. At the subclavian level, each of the trunks (primary bundles) of the brachial plexus is divided into anterior and posterior branches, from which 3 bundles (secondary bundles) are formed that make up the subclavian part of the brachial plexus and are named depending on their location relative to the axillary artery (a. axillaris), which they surround. 1. The posterior bundle is formed by the fusion of all three posterior branches of the trunks of the supraclavicular part of the plexus. From it begin the axillary and radial nerves. 2. The lateral bundle is made up of the joined anterior branches of the upper and partially middle trunks (C5 C6I, C7). From this bundle originate the musculocutaneous nerve and part (external pedicle - C7) of the median nerve. 3. The medial bundle is a continuation of the anterior branch of the lower primary bundle; from it the ulnar nerve, the cutaneous medial nerves of the shoulder and forearm, as well as part of the median nerve (internal pedicle - C8) are formed, which connects to the external pedicle (in front of the axillary artery), together they form a single trunk of the median nerve. Nerves formed in the brachial plexus belong to the nerves of the neck, shoulder girdle and arm. Nerves of the neck. The innervation of the neck involves short muscle branches (rr. musculares), innervating the deep muscles: intertransverse muscles (mm. intertrasversarif); the long muscle of the neck (m. longus colli), tilting the head to its side, and with the contraction of both muscles, tilting it forward; anterior, middle and posterior scalene muscles (mm. scaleni anterior, medius, posterior), which, with a fixed chest, tilt to their side cervical region spine, and with bilateral contraction, tilt it forward; if the neck is fixed, then the scalene muscles, contracting, raise the 1st and 2nd ribs. Nerves of the shoulder girdle. The nerves of the shoulder girdle originate from the supraclavicular part of the brachial plexus and are primarily motor in function. 1. The subclavian nerve (n. subclavius, C5-C6) innervates the subclavian muscle (t. subclavius), which, when contracted, shifts the clavicle down and medially. 2. The anterior pectoral nerves (pp. thoracales anteriores, C5-Th1) innervate the pectoralis major and minor muscles (mm. pectorales major et minor). The contraction of the first of them causes the adduction and rotation of the shoulder inward, the contraction of the second - the displacement of the scapula forward and downward. 3. The suprascapular nerve (p. suprascapular, C5-C6) innervates the supraspinatus and infraspinatus muscles (t. supraspinatus et t. infraspinatus); the first contributes to the abduction of the shoulder, the second rotates it outward. Sensitive branches of this nerve innervate the shoulder joint. 4. The subscapular nerves (pp. subscapulars, C5-C7) innervate the subscapularis muscle (t. subscapularis), which rotates the shoulder inward, and the large round muscle (t. teres major), which rotates the shoulder inward (pronation), abducts it back and leads to the torso. 5. The posterior nerves of the chest (nn, toracaies posteriores): the dorsal nerve of the scapula (n. dorsalis scapulae) and the long nerve of the chest (n. thoracalis longus, C5-C7) innervate the muscles, the contraction of which ensures the mobility of the scapula (i.e. levator scapulae, t. rhomboideus, m. serratus anterior). The last of them helps to raise the hand above the horizontal level. The defeat of the posterior nerves of the chest leads to asymmetry of the shoulder blades. When moving in shoulder joint winged scapula on the side of the lesion is characteristic. 6. The thoracic nerve (p. thoracodorsal, C7-C8) innervates the latissimus dorsi muscle (t. latissimus dorsi), which brings the shoulder to the body, pulls it back to the midline and rotates it inward. Nerves of the hand. The nerves of the hand are formed from the secondary bundles of the brachial plexus. The axillary and radial nerves are formed from the posterior longitudinal bundle, the musculocutaneous nerve and the external pedicle of the median nerve are formed from the external secondary bundle; from the secondary internal bundle - the ulnar nerve, the internal leg of the median nerve and the medial cutaneous nerves of the shoulder and forearm. 1. Axillary nerve (n. axillaris, C5-C7) - mixed; innervates the deltoid muscle (t. deltoideus), which, when contracted, abducts the shoulder to a horizontal level and pulls it back or forward, as well as a small round muscle (t. teres minor), which rotates the shoulder outward. The sensitive branch of the axillary nerve - the upper external cutaneous nerve of the shoulder (n. cutaneus brachii lateralis superior) - innervates the skin above the deltoid muscle, as well as the skin of the outer and partly posterior surface of the upper shoulder (Fig. 8.4). With damage to the axillary nerve, the arm hangs like a whip, the removal of the shoulder to the side forward or backward is impossible. 2. Radial nerve (n. radialis, C7 partly C6, C8, Th1) - mixed; but mainly motor, it innervates mainly the extensor muscles of the forearm - the triceps muscle of the shoulder (t. triceps brachii) and the ulnar muscle (t. apponens), the extensors of the hand and fingers - the long and short radial extensors of the wrist (mm. extensor carpi radialis longus et brevis) and the extensor of the fingers (t. extensor digitorum), the arch support of the forearm (t. supinator), the brachioradialis muscle (t. brachioradialis), which takes part in flexion and pronation of the forearm, as well as the muscles that cover the thumb of the hand ( t. abductor pollicis longus et brevis), short and long extensors of the thumb (t. extensor pollicis brevis et longus), extensor of the index finger (t. extensor indicis). Sensitive fibers of the radial nerve make up the posterior cutaneous branch of the shoulder (n. cutaneus brachii posteriores), which provides sensitivity to the back of the shoulder; the lower lateral cutaneous nerve of the shoulder (n. cutaneus brachii lateralis inferior), which innervates the skin of the lower outer part of the shoulder, and the posterior cutaneous nerve of the forearm (n. cutaneus antebrachii posterior), which determines the sensitivity of the posterior surface of the forearm, as well as the superficial branch (ramus superficialis) , involved in the innervation of the back surface of the hand, as well as the back surface of the I, II and half of the III fingers (Fig. 8.4, fig. 8.5). Rice. 8.4. Innervation of the skin of the surface of the hand (a - dorsal, b - ventral). I - axillary nerve (its branch - the external cutaneous nerve of the shoulder); 2 - radial nerve (posterior cutaneous nerve of the shoulder and posterior cutaneous nerve of the forearm); 3 - musculocutaneous nerve (external cutaneous nerve of the forearm); 4 - internal cutaneous nerve of the forearm; 5 - internal cutaneous nerve of the shoulder; 6 - supraclavicular nerves. Rice. 8.5. Innervation of the skin of the hand. 1 - radial nerve, 2 - median nerve; 3 - ulnar nerve; 4 - external nerve of the forearm (branch of the musculocutaneous nerve); 5 - internal cutaneous nerve of the forearm. Rice. 8.6. Hanging brush with damage to the radial nerve. Rice. 8.7. The test of dilution of the palms and fingers in case of damage to the right radial nerve. On the side of the lesion, bent fingers “glide” along the palm of a healthy hand. A characteristic sign of a lesion of the radial nerve is a hanging brush, located in the position of pronation (Fig. 8.6). Due to paresis or paralysis of the corresponding muscles, extension of the hand, fingers and thumb, as well as supination of the hand with an extended forearm, are impossible; the carporadial periosteal reflex is reduced or not elicited. In the case of a high lesion of the radial nerve, the extension of the forearm is also impaired due to paralysis of the triceps muscle of the shoulder, while the tendon reflex from the triceps muscle of the shoulder is not caused. If you attach your palms to each other, and then try to spread them, then on the side of the lesion of the radial nerve, the fingers do not straighten, sliding along the palmar surface of a healthy hand (Fig. 8.7). The radial nerve is very vulnerable; in terms of the frequency of traumatic lesions, it ranks first among all peripheral nerves. Especially often damage to the radial nerve occurs with fractures of the shoulder. Often, infections or intoxications, including chronic alcohol intoxication, are also the cause of damage to the radial nerve. 3. Musculocutaneous nerve (n. musculocutaneus, C5-C6) - mixed; motor fibers innervate biceps shoulder (t. biceps brachii), which flexes the arm at the elbow joint and supinates the bent forearm, as well as shoulder muscle(t. brachialis) y involved in flexion of the forearm, and the coracobrachial muscle (t. coracobrachial ^ ^ contributing to raising the shoulder anteriorly. Sensory fibers of the musculocutaneous nerve form its branch - the external cutaneous nerve of the forearm (n. cutaneus antebrachii lateralis), providing sensitivity of the skin of the radial side of the forearm to the elevation of the thumb.When the musculocutaneous nerve is damaged, the flexion of the forearm is disturbed.This is especially pronounced with the supinated forearm, since the flexion of the pronated forearm is possible due to the brachioradialis innervated by the radial nerve (i.e. brachioradialis). also prolapse of the tendon reflex from the biceps of the shoulder, raising the shoulder anteriorly.Sensitivity disorder can be detected on the outer side of the forearm (Fig. 8.4) 4. Median nerve (n. medianus) - mixed; formed from part of the fibers of the medial and lateral bundle brachial plexus.At the level of the shoulder, the median nerve does not give branches.The muscular branches (rami musculares) extending from it to the forearm and hand innervate the round pronator (i.e., pronator teres), penetrating the forearm and contributing to its flexion. radial flexor wrist (t. flexor carpi radialis), along with flexion of the wrist, diverts the hand to the radial side and participates in flexion of the forearm. The long palmar muscle (t. palmaris longus) stretches the palmar aponeurosis and is involved in flexion of the hand and forearm. The superficial flexor of the fingers (t. digitorum superficialis) flexes the middle phalanges of the II-V fingers, participates in the flexion of the hand. In the upper third of the forearm, the palmar branch of the median nerve (ramus palmaris n. mediant) departs from the median nerve. It passes in front of the interosseous septum between the long flexor of the thumb and the deep flexor of the fingers and innervates the long flexor of the thumb (i.e. flexor pollicis longus), which flexes the nail phalanx of the thumb; part of the deep flexor of the fingers (t. flexor digitorum profundus), which flexes the nail and middle phalanges of the II-III fingers and the hand; square pronator (t. pronator quadratus), penetrating the forearm and hand. At the level of the wrist, the median nerve divides into 3 common palmar digital nerves (pp. digitaks palmares communes) and their own palmar digital nerves (pp. digitaks palmares proprii) extending from them. They innervate the short muscle that abducts the thumb (t. abductor pollicis brevis), the muscle that opposes the thumb of the hand (t. opponens policis), the short flexor of the thumb (t. flexor pollicis brevis) and I-11 vermiform muscles (mm. lumbricales). Sensitive fibers of the median nerve innervate the skin in the area of ​​the wrist joint (its anterior surface), the eminence of the thumb (thenar), I, II, III fingers and the radial side of the IV finger, as well as the back surface of the middle and distal phalanges of the II and III fingers ( Fig. 8.5). Damage to the median nerve is characterized by a violation of the ability to oppose the thumb to the rest, while the muscles of the elevation of the thumb atrophy over time. The thumb in such cases is in the same plane with the rest. As a result, the palm acquires a typical form for lesions of the median nerve, known as the “monkey hand” (Fig. 8.8a). If the median nerve is affected at the level of the shoulder, there is a disorder of all functions, depending on its condition. To identify impaired functions of the median nerve, the following tests can be carried out: a) when trying to clench the hand into a fist, I, II, and partly III fingers remain extended (Fig. 8.86); if the palm is pressed against the table, then the scratching movement with the nail of the index finger fails; c) to hold a strip of paper between the thumb and forefinger due to the impossibility of bending the thumb, the patient brings the straightened thumb to the index finger - thumb test. Due to the fact that the median nerve contains a large number of vegetative fibers, when it is damaged, trophic disorders are usually pronounced and more often than when any other nerve is damaged, causalgia develops, manifesting itself in the form of sharp, burning, diffuse pain. Rice. 8.8. Damage to the median nerve. a - "monkey brush"; b - when squeezing the hand into a fist, fingers I and II do not bend. 5. Ulnar nerve (p. ulnaris, C8-Th1) - mixed; it begins in the axilla from the medial bundle of the brachial plexus, descends parallel to the axillary and then the brachial artery and goes to the internal condyle of the humerus and at the level of the distal part of the shoulder passes along the groove of the ulnar nerve (sulcus nervi ulnaris). In the upper third of the forearm, branches depart from the ulnar nerve to the following muscles: the ulnar flexor of the hand (i.e., flexor carpi ulnaris), the flexor and adductor hand; the medial part of the deep flexor of the fingers (t. flexor digitorum profundus), which flexes the nail phalanx of the IV and V fingers. In the middle third of the forearm, the cutaneous palmar branch (ramus cutaneus palmaris) departs from the ulnar nerve, innervating the skin of the medial side of the palm in the area of ​​​​the elevation of the little finger (hypotenar). On the border between the middle and lower thirds of the forearm, the dorsal branch of the hand (ramus dorsalis manus) and the palmar branch of the hand (ramus volaris manus) are separated from the ulnar nerve. The first of these branches is sensitive, it goes to the back of the hand, where it branches into the dorsal nerves of the fingers (n. digitales dorsales), which terminate in the skin of the back surface of the V and IV fingers and the ulnar side of the III finger, while the nerve of the V finger reaches its nail phalanx , and the rest reach only the middle phalanges. The second branch is mixed; its motor part is directed to the palmar surface of the hand and at the level of the pisiform bone is divided into superficial and deep branches. The superficial branch innervates the short palmar muscle, which pulls the skin to the palmar aponeurosis, then it is divided into common and proper palmar digital nerves (n. digitales pa / mares communis et proprii). The common digital nerve innervates the palmar surface of the fourth finger and the medial side of its middle and final phalanges, as well as the back side of the nail phalanx of the fifth finger. The deep branch penetrates deep into the palm of the hand, goes to the radial side of the hand and innervates the following muscles: the muscle that leads to the greater palea (t. adductor policis), the adductor V finger (t. abductor digiti minim f), which flexes the main phalanx of the V finger, the muscle , which opposes the V finger (i.e. opponens digiti minimi) - she brings the little finger to the midline of the brush and opposes it; deep head of the short flexor of the thumb (ie flexor pollicis brevis); worm-like muscles (tt. lumbricales), muscles that flex the main and extensor the middle and nail phalanges of the II and IV fingers; palmar and dorsal interosseous muscles (mm. interossei palmales et dorsales), which flex the main phalanges and simultaneously extend the other phalanges of the II-V fingers, as well as the fingers abducting the II and IV from the middle (III) finger and adducting the II, IV and V fingers to the average. Sensitive fibers of the ulnar nerve innervate the skin of the ulnar edge of the hand, the back surface of the V and partly the IV fingers and the palmar surface of the V, IV and partly III fingers (Fig. 8.4, 8.5). In cases of damage to the ulnar nerve due to developing atrophy of the interosseous muscles, as well as hyperextension of the main and flexion of the remaining phalanges of the fingers, a claw-like brush is formed, resembling a bird's paw (Fig. 8.9a). To identify signs of damage to the ulnar nerve, the following tests can be carried out: a) when trying to clench the hand into a fist, V, IV, and partly III, the fingers bend insufficiently (Fig. 8.96); b) scratching movements with the nail of the little finger do not work out with the palm tightly pressed to the table; c) if the palm rests on the table, then spreading and bringing the fingers together are not successful; d) the patient cannot hold a strip of paper between the index and straightened thumbs. To hold it, the patient needs to sharply bend the terminal phalanx of the thumb (Fig. 8.10). 6. Cutaneous internal nerve of the shoulder (n. cutaneus brachii medialis, C8-Th1 - sensitive, departs from the medial bundle of the brachial plexus, at the level of the axillary fossa has connections with the external skin branches (rr. cutani laterales) II and III of the thoracic nerves ( pp. thoracales) and innervates the skin of the medial surface of the shoulder to the elbow joint (Fig. 8.4). Fig. 8.9. Signs of damage to the ulnar nerve: claw-like brush (a), when the hand is compressed into a fist V and IV, the fingers do not bend (b) Fig. 8.10 Thumb test In the right hand, pressing a strip of paper is possible only with a straightened thumb due to its adductor muscle innervated by the ulnar nerve (a sign of damage to the median nerve). thumb (a sign of damage to the ulnar nerve). in the medial groove of his biceps muscle, innervates the skin of the inner surface of the forearm (Fig. 8.4). Syndromes of lesions of the brachial plexus. Along with an isolated lesion of individual nerves emerging from the brachial plexus, damage to the plexus itself is possible. Damage to the plexus is called plexopathy. The etiological factors of damage to the brachial plexus are gunshot wounds of the supraclavicular and subclavian regions, fracture of the clavicle, 1st rib, periostitis of the 1st rib, dislocation of the humerus. Sometimes the plexus is affected due to its overstretching, with a quick and strong abduction of the arm back. Damage to the plexus is also possible in a position where the head is turned in the opposite direction, and the hand is behind the head. Brachial plexopathy can be observed in newborns due to traumatic injury during complicated childbirth. Damage to the brachial plexus can also be caused by carrying weights on the shoulders, on the back, especially with general intoxication with alcohol, lead, etc. The cause of compression of the plexus can be an aneurysm of the subclavian artery, additional cervical ribs, hematomas, abscesses and tumors of the supraclavicular and subclavian region. Total brachial plexopathy leads to flaccid paralysis of all muscles of the shoulder girdle and arm, while only the ability to “lift the shoulder girdle” can be preserved due to the preserved function of the trapezius muscle, innervated by the accessory cranial nerve and the posterior branches of the cervical and thoracic nerves. In accordance with the anatomical structure of the brachial plexus, the syndromes of damage to its trunks (primary bundles) and bundles (secondary bundles) differ. Syndromes of damage to the trunks (primary bundles) of the brachial plexus occur when the supraclavicular part of it is damaged, while syndromes of damage to the upper, middle and lower trunks can be distinguished. I. Syndrome of lesions of the upper trunk of the brachial plexus (the so-called upper brachial plexopathy of Erb-Duchenne>

The brachial plexus (plexus brachialis) is formed from the anterior branches of the C5 Th1 spinal nerves (Fig. 8.3). The spinal nerves, from which the brachial plexus is formed, leave the spinal canal through the corresponding intervertebral foramens, passing between the anterior and posterior intertransverse muscles. The anterior branches of the spinal nerves, connecting with each other, first form 3 trunks (primary bundles) of the brachial plexus that make it up Fig. 8.3. Shoulder plexus. I - primary upper beam; II - primary middle beam; III - primary lower beam; P - secondary posterior bundle; L - secondary outer beam; M - secondary internal beam; 1 - musculocutaneous nerve; 2 - axillary nerve; 3 - radial nerve; 4 - median nerve; 5 - ulnar nerve; 6 - internal cutaneous nerve; 7 - internal cutaneous nerve of the forearm. supraclavicular part, each of which is connected by means of white connecting branches to the middle or lower cervical vegetative nodes. 1. The superior trunk arises from the connection of the anterior branches of the C5 and C6 spinal nerves. 2. The middle trunk is a continuation of the anterior branch of the C7 spinal nerve. 3. The lower trunk consists of the anterior branches of the C8, Th1 and Th2 spinal nerves. The trunks of the brachial plexus descend between the anterior and middle scalene muscles above and behind the subclavian artery and pass into the subclavian part of the brachial plexus, located in the zone of the subclavian and axillary fossae. At the subclavian level, each of the trunks (primary bundles) of the brachial plexus is divided into anterior and posterior branches, from which 3 bundles (secondary bundles) are formed that make up the subclavian part of the brachial plexus and are named depending on their location relative to the axillary artery (a. axillaris), which they surround. 1. The posterior bundle is formed by the fusion of all three posterior branches of the trunks of the supraclavicular part of the plexus. From it begin the axillary and radial nerves. 2. The lateral bundle is made up of the joined anterior branches of the upper and partially middle trunks (C5 C6I, C7). From this bundle originate the musculocutaneous nerve and part (external pedicle - C7) of the median nerve. 3. The medial bundle is a continuation of the anterior branch of the lower primary bundle; from it the ulnar nerve, the cutaneous medial nerves of the shoulder and forearm, as well as part of the median nerve (internal pedicle - C8) are formed, which connects to the external pedicle (in front of the axillary artery), together they form a single trunk of the median nerve. Nerves formed in the brachial plexus belong to the nerves of the neck, shoulder girdle and arm. Nerves of the neck. The innervation of the neck involves short muscle branches (rr. musculares), innervating the deep muscles: intertransverse muscles (mm. intertrasversarif); the long muscle of the neck (m. longus colli), tilting the head to its side, and with the contraction of both muscles, tilting it forward; anterior, middle and posterior scalene muscles (mm. scaleni anterior, medius, posterior), which, with a fixed chest, tilt the cervical spine to their side, and with bilateral contraction, tilt it forward; if the neck is fixed, then the scalene muscles, contracting, raise the 1st and 2nd ribs. Nerves of the shoulder girdle. The nerves of the shoulder girdle originate from the supraclavicular part of the brachial plexus and are primarily motor in function. 1. The subclavian nerve (n. subclavius, C5-C6) innervates the subclavian muscle (t. subclavius), which, when contracted, shifts the clavicle down and medially. 2. The anterior pectoral nerves (pp. thoracales anteriores, C5-Th1) innervate the pectoralis major and minor muscles (mm. pectorales major et minor). The contraction of the first of them causes the adduction and rotation of the shoulder inward, the contraction of the second - the displacement of the scapula forward and downward. 3. The suprascapular nerve (p. suprascapular, C5-C6) innervates the supraspinatus and infraspinatus muscles (t. supraspinatus et t. infraspinatus); the first contributes to the abduction of the shoulder, the second rotates it outward. Sensitive branches of this nerve innervate the shoulder joint. 4. The subscapular nerves (pp. subscapulars, C5-C7) innervate the subscapularis muscle (t. subscapularis), which rotates the shoulder inward, and the large round muscle (t. teres major), which rotates the shoulder inward (pronation), abducts it back and leads to the torso. 5. The posterior nerves of the chest (nn, toracaies posteriores): the dorsal nerve of the scapula (n. dorsalis scapulae) and the long nerve of the chest (n. thoracalis longus, C5-C7) innervate the muscles, the contraction of which ensures the mobility of the scapula (i.e. levator scapulae, t. rhomboideus, m. serratus anterior). The last of them helps to raise the hand above the horizontal level. The defeat of the posterior nerves of the chest leads to asymmetry of the shoulder blades. When moving in the shoulder joint, the winged shape of the scapula on the side of the lesion is characteristic. 6. The thoracic nerve (p. thoracodorsal, C7-C8) innervates the latissimus dorsi muscle (t. latissimus dorsi), which brings the shoulder to the body, pulls it back to the midline and rotates it inward. Nerves of the hand. The nerves of the hand are formed from the secondary bundles of the brachial plexus. The axillary and radial nerves are formed from the posterior longitudinal bundle, the musculocutaneous nerve and the external pedicle of the median nerve are formed from the external secondary bundle; from the secondary internal bundle - the ulnar nerve, the internal leg of the median nerve and the medial cutaneous nerves of the shoulder and forearm. 1. Axillary nerve (n. axillaris, C5-C7) - mixed; innervates the deltoid muscle (t. deltoideus), which, when contracted, abducts the shoulder to a horizontal level and pulls it back or forward, as well as a small round muscle (t. teres minor), which rotates the shoulder outward. The sensitive branch of the axillary nerve - the upper external cutaneous nerve of the shoulder (n. cutaneus brachii lateralis superior) - innervates the skin above the deltoid muscle, as well as the skin of the outer and partly posterior surface of the upper shoulder (Fig. 8.4). With damage to the axillary nerve, the arm hangs like a whip, the removal of the shoulder to the side forward or backward is impossible. 2. Radial nerve (n. radialis, C7 partly C6, C8, Th1) - mixed; but mainly motor, it innervates mainly the extensor muscles of the forearm - the triceps muscle of the shoulder (t. triceps brachii) and the ulnar muscle (t. apponens), the extensors of the hand and fingers - the long and short radial extensors of the wrist (mm. extensor carpi radialis longus et brevis) and the extensor of the fingers (t. extensor digitorum), the arch support of the forearm (t. supinator), the brachioradialis muscle (t. brachioradialis), which takes part in flexion and pronation of the forearm, as well as the muscles that cover the thumb of the hand ( t. abductor pollicis longus et brevis), short and long extensors of the thumb (t. extensor pollicis brevis et longus), extensor of the index finger (t. extensor indicis). Sensitive fibers of the radial nerve make up the posterior cutaneous branch of the shoulder (n. cutaneus brachii posteriores), which provides sensitivity to the back of the shoulder; the lower lateral cutaneous nerve of the shoulder (n. cutaneus brachii lateralis inferior), which innervates the skin of the lower outer part of the shoulder, and the posterior cutaneous nerve of the forearm (n. cutaneus antebrachii posterior), which determines the sensitivity of the posterior surface of the forearm, as well as the superficial branch (ramus superficialis) , involved in the innervation of the back surface of the hand, as well as the back surface of I, II and half of the III fingers (Fig. 8.4, Fig. 8.5). Rice. 8.4. Innervation of the skin of the surface of the hand (a - dorsal, b - ventral). I - axillary nerve (its branch - the external cutaneous nerve of the shoulder); 2 - radial nerve (posterior cutaneous nerve of the shoulder and posterior cutaneous nerve of the forearm); 3 - musculocutaneous nerve (external cutaneous nerve of the forearm); 4 - internal cutaneous nerve of the forearm; 5 - internal cutaneous nerve of the shoulder; 6 - supraclavicular nerves. Rice. 8.5. Innervation of the skin of the hand. 1 - radial nerve, 2 - median nerve; 3 - ulnar nerve; 4 - external nerve of the forearm (branch of the musculocutaneous nerve); 5 - internal cutaneous nerve of the forearm. Rice. 8.6. Hanging brush with damage to the radial nerve. Rice. 8.7. The test of dilution of the palms and fingers in case of damage to the right radial nerve. On the side of the lesion, bent fingers “glide” along the palm of a healthy hand. A characteristic sign of a lesion of the radial nerve is a hanging brush, located in the position of pronation (Fig. 8.6). Due to paresis or paralysis of the corresponding muscles, extension of the hand, fingers and thumb, as well as supination of the hand with an extended forearm, are impossible; the carporadial periosteal reflex is reduced or not elicited. In the case of a high lesion of the radial nerve, the extension of the forearm is also impaired due to paralysis of the triceps muscle of the shoulder, while the tendon reflex from the triceps muscle of the shoulder is not caused. If you attach your palms to each other, and then try to spread them, then on the side of the lesion of the radial nerve, the fingers do not straighten, sliding along the palmar surface of a healthy hand (Fig. 8.7). The radial nerve is very vulnerable; in terms of the frequency of traumatic lesions, it ranks first among all peripheral nerves. Especially often damage to the radial nerve occurs with fractures of the shoulder. Often, infections or intoxications, including chronic alcohol intoxication, are also the cause of damage to the radial nerve. 3. Musculocutaneous nerve (n. musculocutaneus, C5-C6) - mixed; motor fibers innervate the biceps muscle of the shoulder (t. biceps brachii), which flexes the arm at the elbow joint and supinates the bent forearm, as well as the shoulder muscle (t. brachialis) y involved in flexion of the forearm, and the coracobrachial muscle (t. coracobrachial ^ ^ contributing raising the shoulder anteriorly.Sensitive fibers of the musculocutaneous nerve form its branch - the external cutaneous nerve of the forearm (n. cutaneus antebrachii lateralis), which provides sensitivity to the skin of the radial side of the forearm to the elevation of the thumb.When the musculocutaneous nerve is affected, the flexion of the forearm is disturbed. This comes to light especially clearly with the supinated forearm, since flexion of the pronated forearm is possible due to the brachioradialis innervated by the radial nerve (i.e. brachioradialis).Prolapse of the tendon reflex from the biceps of the shoulder, raising the shoulder anteriorly is also characteristic.Sensitivity disorder can be detected on the outside forearms (Fig. 8.4). 4. Median nerve (p. medianus) - mixed; is formed from a part of the fibers of the medial and lateral bundle of the brachial plexus. At shoulder level, the median nerve does not give branches. The muscular branches (rami musculares) extending from it to the forearm and hand innervate the round pronator (i.e. pronator teres), penetrating the forearm and contributing to its flexion. The radial flexor of the wrist (i.e. flexor carpi radialis), along with flexion of the wrist, diverts the hand to the radial side and participates in flexion of the forearm. The long palmar muscle (t. palmaris longus) stretches the palmar aponeurosis and is involved in flexion of the hand and forearm. The superficial flexor of the fingers (t. digitorum superficialis) flexes the middle phalanges of the II-V fingers, participates in the flexion of the hand. In the upper third of the forearm, the palmar branch of the median nerve (ramus palmaris n. mediant) departs from the median nerve. It passes in front of the interosseous septum between the long flexor of the thumb and the deep flexor of the fingers and innervates the long flexor of the thumb (i.e. flexor pollicis longus), which flexes the nail phalanx of the thumb; part of the deep flexor of the fingers (t. flexor digitorum profundus), which flexes the nail and middle phalanges of the II-III fingers and the hand; square pronator (t. pronator quadratus), penetrating the forearm and hand. At the level of the wrist, the median nerve divides into 3 common palmar digital nerves (pp. digitaks palmares communes) and their own palmar digital nerves (pp. digitaks palmares proprii) extending from them. They innervate the short muscle that abducts the thumb (t. abductor pollicis brevis), the muscle that opposes the thumb of the hand (t. opponens policis), the short flexor of the thumb (t. flexor pollicis brevis) and I-11 vermiform muscles (mm. lumbricales). Sensitive fibers of the median nerve innervate the skin in the area of ​​the wrist joint (its anterior surface), the eminence of the thumb (thenar), I, II, III fingers and the radial side of the IV finger, as well as the back surface of the middle and distal phalanges of the II and III fingers ( Fig. 8.5). Damage to the median nerve is characterized by a violation of the ability to oppose the thumb to the rest, while the muscles of the elevation of the thumb atrophy over time. The thumb in such cases is in the same plane with the rest. As a result, the palm acquires a typical form for lesions of the median nerve, known as the “monkey hand” (Fig. 8.8a). If the median nerve is affected at the level of the shoulder, there is a disorder of all functions, depending on its condition. To identify impaired functions of the median nerve, the following tests can be carried out: a) when trying to clench the hand into a fist, I, II, and partly III fingers remain extended (Fig. 8.86); if the palm is pressed against the table, then the scratching movement with the nail of the index finger fails; c) to hold a strip of paper between the thumb and forefinger due to the impossibility of bending the thumb, the patient brings the straightened thumb to the index finger - thumb test. Due to the fact that the median nerve contains a large number of vegetative fibers, when it is damaged, trophic disorders are usually pronounced and more often than when any other nerve is damaged, causalgia develops, manifesting itself in the form of sharp, burning, diffuse pain. Rice. 8.8. Damage to the median nerve. a - "monkey brush"; b - when squeezing the hand into a fist, fingers I and II do not bend. 5. Ulnar nerve (p. ulnaris, C8-Th1) - mixed; it begins in the axilla from the medial bundle of the brachial plexus, descends parallel to the axillary and then the brachial artery and goes to the internal condyle of the humerus and at the level of the distal part of the shoulder passes along the groove of the ulnar nerve (sulcus nervi ulnaris). In the upper third of the forearm, branches depart from the ulnar nerve to the following muscles: the ulnar flexor of the hand (i.e., flexor carpi ulnaris), the flexor and adductor hand; the medial part of the deep flexor of the fingers (t. flexor digitorum profundus), which flexes the nail phalanx of the IV and V fingers. In the middle third of the forearm, the cutaneous palmar branch (ramus cutaneus palmaris) departs from the ulnar nerve, innervating the skin of the medial side of the palm in the area of ​​​​the elevation of the little finger (hypotenar). On the border between the middle and lower thirds of the forearm, the dorsal branch of the hand (ramus dorsalis manus) and the palmar branch of the hand (ramus volaris manus) are separated from the ulnar nerve. The first of these branches is sensitive, it goes to the back of the hand, where it branches into the dorsal nerves of the fingers (n. digitales dorsales), which terminate in the skin of the back surface of the V and IV fingers and the ulnar side of the III finger, while the nerve of the V finger reaches its nail phalanx , and the rest reach only the middle phalanges. The second branch is mixed; its motor part is directed to the palmar surface of the hand and at the level of the pisiform bone is divided into superficial and deep branches. The superficial branch innervates the short palmar muscle, which pulls the skin to the palmar aponeurosis, further it is divided into common and proper palmar digital nerves (pp. digitales pa/mares communis et proprii). The common digital nerve innervates the palmar surface of the fourth finger and the medial side of its middle and final phalanges, as well as the back side of the nail phalanx of the fifth finger. The deep branch penetrates deep into the palm of the hand, goes to the radial side of the hand and innervates the following muscles: the muscle that leads to the greater palea (t. adductor policis), the adductor V finger (t. abductor digiti minim f), which flexes the main phalanx of the V finger, the muscle , opposing the V finger (t. opponens digiti minimi) - it brings the little finger to the midline of the brush and opposes it; deep head of the short flexor of the thumb (ie flexor pollicis brevis); worm-like muscles (tt. lumbricales), muscles that flex the main and extensor the middle and nail phalanges of the II and IV fingers; palmar and dorsal interosseous muscles (mm. interossei palmales et dorsales), which flex the main phalanges and simultaneously extend the other phalanges of the II-V fingers, as well as the fingers abducting the II and IV from the middle (III) finger and adducting the II, IV and V fingers to the average. Sensitive fibers of the ulnar nerve innervate the skin of the ulnar edge of the hand, the back surface of the V and partly the IV fingers and the palmar surface of the V, IV and partly III fingers (Fig. 8.4, 8.5). In cases of damage to the ulnar nerve due to developing atrophy of the interosseous muscles, as well as hyperextension of the main and flexion of the remaining phalanges of the fingers, a claw-like brush is formed, resembling a bird's paw (Fig. 8.9a). To identify signs of damage to the ulnar nerve, the following tests can be carried out: a) when trying to clench the hand into a fist, V, IV, and partly III, the fingers bend insufficiently (Fig. 8.96); b) scratching movements with the nail of the little finger do not work out with the palm tightly pressed to the table; c) if the palm rests on the table, then spreading and bringing the fingers together are not successful; d) the patient cannot hold a strip of paper between the index and straightened thumbs. To hold it, the patient needs to sharply bend the terminal phalanx of the thumb (Fig. 8.10). 6. Cutaneous internal nerve of the shoulder (n. cutaneus brachii medialis, C8-Th1 - sensitive, departs from the medial bundle of the brachial plexus, at the level of the axillary fossa has connections with the external skin branches (rr. cutani laterales) II and III of the thoracic nerves ( pp. thoracales) and innervates the skin of the medial surface of the shoulder to the elbow joint (Fig. 8.4). Fig. 8.9. Signs of damage to the ulnar nerve: claw-like brush (a), when the hand is compressed into a fist V and IV, the fingers do not bend (b) . Rns. 8.10. Thumb test. In the right hand, pressing a strip of paper is possible only with a straightened thumb due to its adductor muscle, innervated by the ulnar nerve (a sign of damage to the median nerve). On the left, the paper strip is pressed by the long muscle innervated by the median nerve, which flexes the thumb (a sign of damage to the ulnar nerve). 7. Cutaneous internal nerve of the forearm (n. cutaneus antebrachii medialis, C8-7h2) - sensitive, departs from the medial bundle of the brachial plexus, in the axillary fossa is located next to the ulnar nerve, descends along the shoulder in the medial groove of its biceps muscle, innervates the skin of the internal early surface of the forearm (Fig. 8.4). Syndromes of lesions of the brachial plexus. Along with an isolated lesion of individual nerves emerging from the brachial plexus, damage to the plexus itself is possible. Damage to the plexus is called plexopathy. The etiological factors of damage to the brachial plexus are gunshot wounds of the supraclavicular and subclavian regions, fracture of the clavicle, 1st rib, periostitis of the 1st rib, dislocation of the humerus. Sometimes the plexus is affected due to its overstretching, with a quick and strong abduction of the arm back. Damage to the plexus is also possible in a position where the head is turned in the opposite direction, and the hand is behind the head. Brachial plexopathy can be observed in newborns due to traumatic injury during complicated childbirth. Damage to the brachial plexus can also be caused by carrying weights on the shoulders, on the back, especially with general intoxication with alcohol, lead, etc. The cause of compression of the plexus can be an aneurysm of the subclavian artery, additional cervical ribs, hematomas, abscesses and tumors of the supraclavicular and subclavian region. Total brachial plexopathy leads to flaccid paralysis of all muscles of the shoulder girdle and arm, while only the ability to “lift the shoulder girdle” can be preserved due to the preserved function of the trapezius muscle, innervated by the accessory cranial nerve and the posterior branches of the cervical and thoracic nerves. In accordance with the anatomical structure of the brachial plexus, the syndromes of damage to its trunks (primary bundles) and bundles (secondary bundles) differ. Syndromes of damage to the trunks (primary bundles) of the brachial plexus occur when the supraclavicular part of it is damaged, while syndromes of damage to the upper, middle and lower trunks can be distinguished. I. Syndrome of damage to the upper trunk of the brachial plexus (the so-called upper brachial plexopathy of Erb-Duchenne> occurs when the anterior branches of the V and VI cervical spinal nerves are damaged (traumatic) or the part of the plexus in which these nerves are connected, forming after passing between the scalene muscles of the upper trunk. This place is located 2-4 cm above the collarbone, approximately a finger's width behind the sternocleidomastoid muscle and is called Erb's supraclavicular point. Upper brachial Erb-Duchenne plexopathy is characterized by a combination of signs of damage to the axillary nerve, long thoracic nerve, anterior thoracic nerves, subscapular nerve, dorsal nerve of the scapula, musculocutaneous and part of the radial nerve. Characterized by paralysis of the muscles of the shoulder girdle and proximal parts of the arm (deltoid, biceps, brachial, brachioradial muscles and arch support), impaired shoulder abduction, flexion and supination of the forearm. As a result, the hand hangs down like a whip, is adducted and pronated, the patient cannot raise his hand, bring his hand to his mouth. If the hand is passively supinated, it will immediately turn inward again. The reflex from the biceps muscle and the radiocarpal (carporadial) reflex are not evoked, and radicular type hypalgesia usually occurs on the outer side of the shoulder and forearm in the Cv-CVI dermatome zone. Palpation reveals pain in the supraclavicular Erb point. A few weeks after the defeat of the plexus, an increasing hypotrophy of the paralyzed muscles appears. Erb-Duchenne brachial plexopathy often occurs with injuries, it is possible, in particular, when falling on an outstretched arm, it may be a consequence of plexus compression during a long stay with the arms wound under the head. Sometimes it appears in newborns with pathological childbirth. 2. Syndrome of damage to the middle trunk of the brachial plexus occurs when the anterior branch of the VII cervical spinal nerve is damaged. In this case, violations of the extension of the shoulder, hand and fingers are characteristic. However, the three-headed muscle of the shoulder, the extensor of the thumb and the long abductor of the thumb are not completely affected, since along with the fibers of the VII cervical spinal nerve, fibers that have come to the plexus along the anterior branches of V and VI also participate in their innervation. cervical spinal nerves. This circumstance is an important sign in the differential diagnosis of the syndrome of damage to the middle trunk of the brachial plexus and selective damage to the radial nerve. The reflex from the tendon of the triceps muscle and the wrist (carpo-radial) reflex are not called. Sensitive disturbances are limited to a narrow band of hypalgesia on the dorsal surface of the forearm and the radial part of the dorsal surface of the hand. 3. The syndrome of lesions of the lower trunk of the brachial plexus (lower brachial plexopathy Dejerine-Klumpke) occurs when the nerve fibers entering the plexus along the VIII cervical and I thoracic spinal nerves are damaged, with signs of damage to the ulnar nerve and cutaneous internal nerves of the shoulder and forearm, and also parts of the median nerve (its inner pedicle). In this regard, with Dejerine-Klumke paralysis, paralysis or paresis of the muscles, mainly of the distal part of the arm, occurs. It suffers mainly from the ulnar part of the forearm and hand, where sensory disturbances and vasomotor disorders are detected. It is impossible or difficult to extend and abduct the thumb due to paresis of the short extensor of the thumb and the muscle that abducts the thumb, innervated by the radial nerve, since the impulses going to these muscles pass through the fibers that are part of the VIII cervical and I thoracic spinal cords. cerebral nerves and the lower trunk of the brachial plexus. Sensitivity on the arm is impaired on the medial side of the shoulder, forearm and hand. If, simultaneously with the defeat of the brachial plexus, the white connecting branches leading to the stellate node (ganglion stellatum) also suffer, then manifestations of Horner's syndrome are possible (narrowing of the pupil, palpebral fissure and mild enophthalmos. In contrast to the combined paralysis of the median and ulnar non- ditches, the function of the muscles innervated by the external leg of the median nerve, with the syndrome of the lower trunk of the brachial plexus, is preserved.Dejerine-Klumke palsy often occurs due to a traumatic lesion of the brachial plexus, but may also be the result of compression of it by the cervical rib or Pancoast's tumor.Syndromes of lesions of the bundles (secondary bundles) of the brachial plexus arise in pathological processes and injuries in the subclavian region and, in turn, are divided into lateral, medial and posterior fascicular syndromes.These syndromes practically correspond to the clinic of the combined lesion of the peripheral nerves formed from the corresponding bundles of the brachial plexus. bundle is manifested by a violation of the functions of the musculocutaneous nerve and the upper pedicle of the median nerve, the syndrome of the posterior bundle is characterized by a violation of the functions of the axillary and radial nerve, and the syndrome of the medial bundle is expressed by a violation of the functions of the ulnar nerve, the medial pedicle of the median nerve, medial cutaneous nerves shoulders and forearms. With the defeat of two or three (all) bundles of the brachial plexus, there is a corresponding summation of clinical signs characteristic of syndromes in which its individual bundles are affected.

The number of pairs of spinal nerves and their localization correspond to the segments of the spinal cord: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal pair. All of them depart from the spinal cord with posterior sensory and anterior motor roots. The roots are combined into one trunk and exit the spinal canal through the intervertebral foramen. In the region of the intervertebral foramen there are spinal nodes (ganglion spinale), which are an accumulation of sensitive cells and are part of the posterior roots. Sensory fibers begin from the cells of the spinal ganglion, and motor fibers from the cells of the anterior horn. When united, the nerves become mixed. After exiting the intervertebral foramen, the spinal nerves divide into posterior and anterior mixed branches. The posterior ones go to the muscles and skin of the posterior parts of the trunk, and the anterior ones innervate the muscles of the anterior part of the trunk and limbs. Combining with each other in other departments, the nerves form the cervical, brachial, lumbar and sacral plexuses.

The cervical plexus (plexus cervicalis) (Fig. 268, 269, 270, 277) is formed as a result of the union of the branches of the four upper cervical nerves and is located on the deep muscles of the neck. Coming out from under the posterior edge of the sternocleidomastoid muscle, the branches of the cervical plexus are divided into sensory, motor and mixed.

Sensitive branches include:

- small occipital nerve (n. occipitalis minor) (Fig. 268, 270), heading to the skin of the back of the head;

- large ear nerve (n. auricularis magnus) (Fig. 268, 270), which innervates the skin of the earlobe and the convex side of the auricle;

- transverse nerve of the neck (n. transversus colli), heading to the skin of the neck;

- supraclavicular nerves (nn. supraclaviculares) (Fig. 268, 273), passing under the clavicle and above the deltoid muscle.

The motor branches go to the deep muscles of the neck and the muscles located below the hyoid bone, and also innervate the sternocleidomastoid and trapezius muscles.

The mixed branch of the cervical plexus is the phrenic nerve (n. phrenicus) (Fig. 268, 269, 271). The motor fibers of the phrenic nerve are sent to the diaphragm, and the sensory fibers innervate the pleura and pericardium.

The brachial plexus (plexus brachialis) (Fig. 268, 273, 277) is formed by the branches of the four lower cervical nerves and the anterior branch of the 1st thoracic nerve. The branches of the plexus go to the neck between the anterior and middle scalene muscles and go to the axillary region. The plexus consists of the supraclavicular section, formed by short branches directed to the shoulder girdle, chest and back, and the subclavian section, which includes long branches that innervate the skin and muscles of the free part of the upper limb (with the exception of the axillary nerve (n. axillaris) (Fig. . 268, 272, 273), going to the shoulder girdle).

	Rice. 268. Scheme of spinal nerves: 1 - a large ear nerve; 2 - small occipital nerve; 3 - supraclavicular nerves; 4 - nerves of the cervical plexus; 5 - subclavian nerve; 6 - suprascapular nerve; 7 - brachial plexus; 8 - phrenic nerve; 9 - subscapular nerve; 10 - median nerve; 11 - musculocutaneous nerve; 12 - thoracic nerve; 13 - axillary nerve; 14 - long thoracic nerve; 15 - medial cutaneous nerve of the shoulder; 16 - a large splanchnic nerve; 17 - radial nerve; 18 - ulnar nerve; 19 - medial cutaneous nerve of the forearm; 20 - intercostal nerves; 21 - small splanchnic nerve; 22 - nerves of the lumbar plexus; 23 - ilio-hypogastric nerve; 24 - ilio-inguinal nerve; 25 - nerves of the sacral plexus; 26 - genital-femoral nerve; 27 - upper gluteal nerve; 28 - lower gluteal nerve; 29 - posterior cutaneous nerve of the thigh; 30 - obturator nerve; 31 - sciatic nerve
	Rice. 269. Plexus of spinal nerves (front view): 1 - cervical plexus; 2 - phrenic nerve; 3 - sympathetic trunk; 4 - median nerve; 5 - intercostal nerves; 7 - cerebral cone; 8 - ilio-inguinal nerve; 9 - lumbar plexus; 10 - lateral cutaneous nerve of the thigh; 11 - sacral plexus; 12 - femoral nerve; 13 - obturator nerve; 14 - anterior cutaneous branches of the femoral nerve
	Rice. 270. Plexus of spinal nerves (rear view): 1 - large occipital nerve; 2 - small occipital nerve; 3 - a large ear nerve; 4 - nerves of the cervical plexus; 5 - lateral cutaneous nerve of the shoulder; 6 - posterior cutaneous branches of the thoracic nerves; 7 - nerves of the lumbar plexus; 8 - nerves of the sacral plexus
	Rice. 271. Nerves of the diaphragm: 1 - muscle that lifts the spine; 2 - external oblique muscle of the abdomen; 3 - internal oblique muscle of the abdomen; 4 - thoracic aorta; 5 - esophagus; 6 - right phrenic nerve; 7 - inferior vena cava; 8 - left phrenic nerve
	Rice. 272. Nerves of the shoulder girdle: 1 - lateral thoracic nerve; 2 - subscapular nerve; 3 - axillary nerve; 4 - thoracic nerve; 5 - musculocutaneous nerve; 6 - medial cutaneous nerve of the shoulder; 7 - radial nerve; 8 - median nerve; 9 - medial cutaneous nerve of the forearm; 10 - ulnar nerve; 11 - lateral cutaneous nerve of the forearm
	Rice. 273. Scheme of the nerves of the upper limb: 1 - supraclavicular nerve; 2 - brachial plexus; 3 - musculocutaneous nerve; 4 - axillary nerve; 5 - medial cutaneous nerve of the shoulder; 6 - lateral cutaneous nerve of the shoulder; 7 - ulnar nerve; 8 - median nerve; 9 - radial nerve; 10 - lateral cutaneous nerve of the forearm; 11 - medial cutaneous nerve of the forearm; 12 - superficial branch of the ulnar nerve; 13 - deep branch of the ulnar nerve; 14 - common palmar digital nerves; 15 - own palmar digital nerves
	Rice. 274. Nerves of the hand: 1 - ulnar nerve; 2 - median nerve; 3 - superficial branches of the ulnar nerve; 4 - common palmar digital nerves; 5 - own palmar digital nerves
	Rice. 275. Intercostal nerves: 1 - spinal cord; 2 - spinal nerve; 3 - central intercostal nerves; 4 - thoracic aorta; 5 - lateral cutaneous thoracic branch; 6 - external intercostal muscle; 7 - anterior cutaneous thoracic branch; 8 - internal intercostal muscle
	Rice. 276. Scheme of the nerves of the lower limb: 1 - ilio-hypogastric nerve; 2 - obturator nerve; 3 - ilio-inguinal nerve; 4 - femoral nerve; 5 - genital-femoral nerve; 6 - lateral cutaneous nerve of the thigh; 7 - sciatic nerve; 8 - posterior cutaneous nerve of the thigh; 9 - common peroneal nerve; 10 - tibial nerve; 11 - medial cutaneous nerve of the calf; 12 - deep peroneal nerve; 13 - saphenous nerve; 14 - superficial peroneal nerve; 15 - lateral cutaneous nerve of the calf; 16 - sural nerve; 17 - medial and lateral plantar branches
	Rice. 277. Projection of nerve plexuses on the spinal column: 1 - cervical plexus; 2 - brachial plexus; 3 - intercostal nerves; 4 - lumbar plexus; 5 - sacral plexus
	Fig.278. Area of ​​innervation of the body (front view): I - skin branches of the cervical plexus; II - supraclavicular nerves; V - anterior cutaneous branches of the intercostal nerves; VI - lateral cutaneous branches of the intercostal nerves; VII - lateral cutaneous branch of the iliac-hypogastric nerve; VIII - anterior cutaneous branches of the iliac-hypogastric nerve; IX - ilio-inguinal nerve; X - lateral cutaneous nerve of the thigh; XI - branches of the genital-femoral nerve; XII - branches of the sacral plexus; XIII - anterior cutaneous branches of the femoral nerve; XIV - cutaneous branch of the obturator nerve
	Rice. 279. Areas of innervation of the trunk (rear view): I - suprascapular nerve; II - lateral cutaneous nerve of the forearm; III - lateral cutaneous branches of the thoracic nerves; IV - medial cutaneous nerve of the shoulder; V - posterior cutaneous nerve of the shoulder; VI - lateral cutaneous branches of the intercostal nerves; VII - medial cutaneous branches of the thoracic nerves; VIII - branches of the lumbar nerves; IX - medial cutaneous branches of the sacral nerves; X - lateral cutaneous branch of the iliac-hypogastric nerve; XI - lateral cutaneous nerve of the thigh; XII - branches of the posterior cutaneous nerve of the thigh
Rice. 280. Areas of innervation of the upper limb A - palmar surface; B - back surface: I - transverse nerve of the neck; II - subclavian nerves; III - lateral cutaneous nerve of the forearm; IV - branches of the thoracic nerves; V - medial cutaneous nerve of the shoulder; VI - posterior cutaneous nerve of the shoulder; VII - lateral cutaneous nerve of the forearm;	VIII - medial cutaneous nerve of the forearm; IX - branches of the median nerve; X - branches of the ulnar nerve; XI - branches of the radial nerve; XII - deep branches of the median nerve; XIII - deep branches of the ulnar nerve; XIV - branches of intercostal nerves; XV - posterior cutaneous nerve of the forearm; XVI - deep branches of the radial nerve
	Rice. 281. Areas of innervation of the lower limb A - front surface; B - back surface: I - lateral cutaneous branch of the iliac-hypogastric nerve; II - branches of the genital-femoral nerve; III - iliac-inguinal nerve; IV - lateral cutaneous nerve of the thigh; V - cutaneous branch of the obturator nerve; VI - anterior cutaneous nerve of the thigh; VII - branches of the saphenous nerve; VIII - branches of the common peroneal nerve; IX - branches of the superficial peroneal nerve; X - branches of the sural nerve; XI - branches of the deep peroneal nerve; XII - branches of the lumbar nerves; XIII - medial cutaneous branches of the sacral nerves; XIV - posterior cutaneous nerve of the thigh; XV - branches of the tibial nerve
	Rice. 282. Areas of innervation of the head and neck: I - branches of the frontal, ophthalmic and trigeminal nerves; II - branches of the zygomatic, infraorbital, maxillary and trigeminal nerves; III - branches of the large occipital nerve; IV - branches of the ear-occipital, chin, mandibular and trigeminal nerves; V - branches of the small occipital nerve; VI - branches of the large ear nerve; VII - subcutaneous branches of the dorsal nerve of the scapula; VIII - transverse nerve of the neck; IX - supraclavicular nerves

The supraclavicular section includes:

- dorsal nerve of the scapula (n. dorsalis scapulae), which goes to the rhomboid muscle and the muscle that lifts the scapula;

- long thoracic nerve (n. thoracicus longus), innervating the serratus anterior;

- medial and lateral pectoral nerves (nn. pectorales medialis et lateralis) (Fig. 272), going to the large and small pectoral muscles;

- subclavian nerve (n. subclavius), which innervates the subclavian muscle;

- suprascapular nerve (n. suprascapularis) (Fig. 268), next to the supraspinatus and infraspinatus muscles;

- subscapular nerve (n. subscapularis) (Fig. 268, 272), heading to the subscapularis muscle and a large round muscle;

- thoracic nerve (n. thoracodorsalis) (Fig. 268, 272), which is a branch of the subscapular nerve and innervates the latissimus dorsi muscle.

The subclavian region is located in the axillary region and consists of three bundles: medial, lateral and posterior. The trunks of these bundles innervate the axillary artery and are the beginning of long branches.

The medial trunk includes:

- medial cutaneous nerve of the shoulder (n. cutaneus brachii medialis) (Fig. 268, 269, 272, 273), heading to the skin of the medial surface of the shoulder;

- medial cutaneous nerve of the forearm (n. cutaneus antebrachii medialis), innervating the skin of the medial surface of the forearm;

- ulnar nerve (n. ulnaris) (Fig. 268, 272, 273, 274), which is mixed. Its sensory fibers are sent to the skin of the medial parts of the hand. On the palmar surface, they innervate the skin of the 5th finger and the ulnar side of the 4th finger, on the back surface - the skin of the 4th and 5th fingers and the ulnar side of the 3rd finger. The motor fibers on the forearm are directed to the ulnar flexor of the wrist and the medial section of the deep flexor of the fingers. On the hand, they innervate the adductor thumb muscle, the little finger elevation muscles, and the 3rd–4th worm-like muscles.

The lateral trunk includes:

- median nerve (n. medianus) (Fig. 268, 269, 272, 273, 274), which also refers to mixed. It emerges from the lateral and medial trunks. Sensitive fibers are sent to the skin of the lateral part of the palmar surface and the skin of the I, II and III fingers, as well as to the radial side of the IV finger and partly to the back surface of these fingers. The motor fibers on the forearm innervate the flexors of the forearm, with the exception of the flexor carpi ulnaris and the deep flexor of the fingers, and also go to the square and round pronators. On the hand, the motor part innervates the muscles of the elevation of the thumb;

- musculocutaneous nerve (n. musculocutaneus) (Fig. 268, 272, 273), which is mixed. Its branches are sent to the flexors of the anterior surface of the shoulder;

- lateral cutaneous nerve of the forearm (n. cutaneus anterbrachii lateralis), which is the terminal branch of the previous nerve and innervates the forearm.

Rear stem includes:

- radial nerve (n. radialis) (Fig. 268, 272, 273), which is mixed. Sensitive fibers are sent to the skin of the lateral sections of the dorsum of the hand and I, II fingers, as well as the radial side of the III finger. Motor fibers innervate the extensors of the shoulder and forearm;

- posterior cutaneous nerve of the shoulder (n. cutaneus brachii posterior), which is a sensitive branch of the radial nerve and goes to the skin of the back of the shoulder;

- posterior cutaneous nerve of the forearm (n. cutaneus anterbrachii posterior), which is also a sensitive branch of the radial nerve and innervates the skin of the posterior surface of the forearm.

The anterior branches of the thoracic nerves do not form plexuses. Intercostal nerves (nn. intercostales) (Fig. 268, 269, 275, 277) are mixed and depart from the posterior branches. Their sensory fibers are sent to the skin of the chest and abdomen, and the motor fibers are directed to the intercostal muscles, the muscles that lift the ribs, the serratus posterior muscles, the transverse chest muscle, as well as the transverse and rectus abdominis muscles, the external and internal oblique muscles of the abdomen.

The lumbar plexus (plexus lumbalis) (Fig. 268, 269, 270, 277) is formed by the branches of the 12th thoracic nerve and the 1-4th lumbar nerve and lies behind and partially in the thickness of the psoas major muscle, from under the lateral edge of which exit branches of the lumbar plexus:

- ilio-hypogastric nerve (n. iliohypogastricus) (Fig. 268, 276), belonging to the mixed. Its sensory fibers go to the skin above the tensor fascia lata and middle gluteal muscle th, as well as to the skin of the suprapubic region. Motor fibers are sent to the external and internal oblique and rectus abdominis muscles;

- ilioinguinal nerve (n. ilioinguinalis) (Fig. 268, 269, 276), which is also mixed, the sensory fibers of which innervate the skin of the scrotum in men and the labia in women, and the motor fibers are sent to the iliac muscle and the square muscle of the lower back;

- genitofemoral nerve (n. genitofemoralis) (Fig. 268, 276), which is mixed, consists of two branches. Branches of the genital branch (r. genitalis) innervate the fleshy membrane of the scrotum and the muscle that lifts the testicle. The femoral branch (r. femoralis) goes to the skin below the inguinal ligament;

- lateral cutaneous nerve of the thigh (n. cutaneus femoris lateralis) (Fig. 269, 276), which is sensitive and innervates the skin of the lateral surface of the thigh;

- obturator nerve (n. obturatorius) (Fig. 268, 269, 276), which is mixed. Its sensory fibers go to the skin of the lower part of the medial surface of the thigh, and the motor fibers go to the muscles of the medial thigh group;

- femoral nerve (n. femoralis) (Fig. 269, 276), which belongs to the mixed and is the largest nerve of the lumbar plexus. Anterior cutaneous branches (rr. cutanei anteriores) (Fig. 276) are sensitive and directed to the skin of the anterior thigh. The saphenous nerve (n. saphenus) (Fig. 276) - the longest branch of the femoral nerve - goes along the great saphenous vein and gives many branches that go to the skin of the anteromedial section of the lower leg and the medial sections of the dorsum of the foot. Muscular branches (rr. musculares) of the femoral nerve are sent to the psoas major muscle, iliac muscle, quadriceps and tailor muscles of the thigh.

The sacral plexus (plexus sacralis) (Fig. 268, 269, 270, 277) form the anterior branches of the 4th-5th lumbar nerves, the anterior branches of the sacral nerves and the coccygeal nerve. The branches are divided into short and long and go to the large sciatic foramen, forming a triangular plate located on the anterior surface of the piriformis muscle.

Short branches include:

- muscle branches (rr. musculares), innervating the square muscle of the thigh, upper and lower twin muscles, piriformis and obturator internus muscles;

- superior gluteal nerve (n. gluteus superior) (Fig. 268), which innervates the tensor fascia lata, gluteus medius and minimus;

- lower gluteal nerve (n. gluteus inferior) (Fig. 268), heading to the gluteus maximus muscle;

- pudendal nerve (n. genitalis) refers to mixed. Sensory fibers innervate the skin of the perineum and external genitalia, and motor fibers innervate the muscles of the perineum.

Long branches include:

- posterior cutaneous nerve of the thigh (n. cutaneus femoris posterior) (Fig. 268, 276), which is sensitive and goes to the skin of the back of the thigh;

- sciatic nerve (n. ischiadicus) (Fig. 268, 276), which belongs to the mixed and is the largest nerve in the human body. Many branches depart from it, heading to the muscles of the posterior thigh group. The nerve itself descends to the top of the popliteal fossa, where it divides into the tibial and peroneal nerves.

Tibial nerve (n. tibialis) (Fig. 276) runs along the posterior tibial artery between the deep and superficial flexors of the lower leg and behind the medial malleolus of the tibia goes to the plantar surface of the foot. In the region of the popliteal fossa, the tibial nerve gives the following branches:

- the medial cutaneous nerve of the calf (n. cutaneus surae medialis) (Fig. 276) goes to the skin of the posteromedial surface of the leg. In the lower part of the lower leg, it unites with the lateral cutaneous nerve of the calf. Together they form the gastrocnemius nerve (n. suralis), passing behind the lateral ankle and innervating the lateral sections of the dorsum of the foot;

- muscle branches (rr. musculares) innervate the muscles of the posterior surface of the lower leg.

On the lower leg, the tibial nerve gives the following branches:

- medial calcaneal branches (rr. calcanei medialis) are sent to the skin of the medial sections of the heel;

- muscle branches (rr. musculares) innervate the deep layer of the posterior muscle group of the leg.

On the surface of the foot, the tibial nerve divides into medial and lateral plantar branches (rr. plantares medialis et lateralis), which are mixed and follow in the same direction as the plantar arteries. Sensitive fibers of the medial plantar nerve are sent to the skin of the medial part of the sole of the foot and to the skin of I, II, III, IV fingers.

The motor fibers are sent to the short flexor of the fingers, the muscle that removes the big toe and the 1-2nd worm-like muscles. The motor fibers of the lateral plantar nerve innervate the short flexor of the little toe, the muscle that abducts the little toe, the muscle that adducts the big toe, the square muscle of the sole, the interosseous muscles and the 3-4th worm-like muscles.

The common peroneal nerve (n. fibularis communis) (Fig. 276) refers to mixed and in the lateral part of the popliteal fossa is divided into superficial and deep peroneal nerves. The main branches of the common peroneal nerve are:

- lateral cutaneous nerve of the calf (n. cutaneus surae late-ralis) (Fig. 276), which goes to the skin of the posterolateral parts of the lower leg and combines with the medial cutaneous nerve of the calf;

- superficial peroneal nerve (n. fibularis superficialis), which is mixed. Its sensory fibers innervate most of the skin on the dorsum of the foot, and the motor fibers innervate the long and short peroneal muscles;

- deep peroneal nerve (n. fibularis profundus) (Fig. 276), following along the tibial artery. Its sensitive branch gives many branches to the skin of the dorsum of the foot in the region of the first interdigital space. The motor fibers innervate the anterior leg muscles and the muscles of the dorsum of the foot.