Radial nerve in the middle third of the shoulder. Radial artery, veins and superficial branch of the radial nerve

The radial nerve is one of the largest nerves brachial plexus. Moves down the back wall humerus, innervating the triceps muscle of the shoulder and the muscle of the forearm. Also conducts sensation directly to the skin of the shoulder, forearm, lower and upper side thumb. This nerve is mixed, it provides the motor function of the arm, extension, abduction and adduction.

Damage to the radial nerve is a pathology in any area, characterized by a certain origin. It manifests itself in the form of a hanging hand and the inability to independently straighten the hand or elbow joint. It can also be caused by loss of sensation in the shoulder area.

The nerve consists of nerve fibers, which, in turn, have three segments. From the brachial plexus, the radial nerve gives off a branch at the level chest muscle. In the area of ​​​​the armpit, it thickens significantly. But after moving away from the armpit, approximately in the area of ​​​​the middle of the shoulder, it becomes much thinner. In this case, innervation occurs only in the zones of the hand and forearm. The largest accumulation of nerve bundles occurs in the armpit, and the smallest in the region of a third of the shoulder.

The radial nerve has branches:

• Articular - tends to the shoulder joint;
• Posterior cutaneous nerve - innervates the skin of the back of the shoulder;
• Lower lateral cutaneous nerve of the shoulder - moves next to the previous one, but still branches in the skin of the lateral and lower third of the shoulder;
• The branches of the muscles, they are divided into proximal (located closer to the center), lateral (or lateral) and medial (middle). These branches innervate the triceps muscle, the ulnar, as well as the radial and shoulder muscles;
• The posterior cutaneous nerve of the forearm passes through the axillary and brachial canals. Scatters many nerve branches to the skin;
• The branch is superficial, is the final branch in the region of the shoulder joint. It tends to the back of the hand, where it gives innervation to the skin of the inner side of 1, 2 and the central side of 3 fingers;
• Deep, passes through the arch support in the region of the neck of the radius and goes to the inside of the forearm. In this place, there is a breakdown into many muscle branches, which give sensitivity to the extensor muscles.

neuropathy

The defeat of the radial nerve occurs quite often. It can be damaged by squeezing or an uncomfortable position of the hand in a dream, injury, fracture. With long walking on crutches and during compression with hooks during operations. Violation of innervation can also be observed due to squeezing it by a tumor extending from neighboring tissue. Malignant neoplasm is extremely rare in this place.

Damage to the ulnar nerve is fraught with disorders of the motor functions of the hand.

If the elbow is severely injured, active flexion and extension of the fingers is temporarily impossible. Atrophy may develop within a few months interosseous muscles. You can see the manifestation of metacarpal bones on the inside of the palm. The middle phalanges often take a bent position. If the damage touches the shoulder area, then the extensors of the middle phalanges suffer. A contusion of the ulnar plexus absolutely does not impair the function of the triceps muscle. But if the wrist part is damaged, it primarily suffers inner part palms. pain not observed in this injury. However, the back of the hand swells and becomes cold.

Damage to the median nerve leads to a violation and even loss of sensitivity in the place of its innervation. The skin in this area becomes shiny, thin and dry. The nails of the first three fingers are transversely striated. Damage to the median nerve below leads to paralysis of the base of the thumb, and if the upper part is damaged, the flexor of the palm is disturbed. The motor function of the thumb is almost completely impaired. The result of this process is muscle atrophy. If the injury is quite old, more than a year, then the restoration of the innervation of the hand is impossible.

If the neuralgia of the radial nerve touches the axillary region, the extensor functions of the forearm and hand suffer. There is a syndrome of "falling" or "hanging" brush. The back of the hand and phalanx of 1-3 fingers suffer.

The cause of nerve damage can be fractures of the bones of the upper shoulder girdle, as well as when applying a tourniquet. In rare cases, the cause may be an incorrect injection into the shoulder. Also, the above reasons include injuries of a different nature or a strong blow.

Another risk factor may be various intoxications, bacterial and viral infections, or lead poisoning.

Diagnostics

One of the main tasks of neuralgia is the correct diagnosis. The disease develops abruptly, with acute pain. Symptoms and signs of lesions are very similar to each other. It is rather difficult to differentiate the lesion of the ulnar and median nerves. For proper diagnosis, a number of neurological tests are used.

What tests are used to diagnose:

• Hands are touching each other internal parties palms, fingers extended. Then simultaneously each finger is retracted from each other. In the place where there is a nerve lesion, palmar flexion of the fingers is observed;
• In the next test, the doctor asks to shake his hand or make a fist; with neurological disorders, the “hanging” hand syndrome manifests itself;

Various functional tests to determine the sensitivity make it possible to differentiate ulnar neuropathy from radial and median nerve neuropathy.

Violations are divided into primary and secondary. Primary - acquired as a result of bruises or when the tumor squeezes adjacent tissues. Secondary include, for example, with swelling of the tissues or the transformation of the nerve into a scar. There are separate (isolated) and mixed (involvement in the pathological process of blood vessels). Symptoms depend on the area of ​​damage and the very nature of the pathological process.

Treatment

What to do with damage to the radial nerve? Immediately consult a doctor for an accurate diagnosis of the lesion. If a neurological examination is carried out in time and the disease is treated with the provided scheme, then the recovery will be quite fast and effective. Traditionally, therapy will be aimed at relieving pain and restoring the damaged area. Medications include:

• non-steroidal anti-inflammatory drugs;
• vitamins, complex, group B and calcium preparations;
• blockade painkillers, for example, novocaine;
• analgesics;
• diuretic drugs.

Often, the complex of conservative treatment includes physiotherapy, physiotherapy, acupuncture and massages. If, when using complex treatment for several months, no improvement is observed, then the doctor has to stitch the nerve. It's already radical methods treatment. These include the removal of tumors at the site of nerve compression. It is advisable to resort to surgical intervention and with combined damage to the nerve and bone or vessel. Such operations are done in several stages. Neurolysis is a common indication for surgery. This is the release of the nerve from the scar tissue. Operations are considered more effective with early intervention.

• We place the arm in a bent position on a hard surface, so that the forearm is perpendicular to this surface. Raise your thumb up and pull your thumb down. Repeat the exercise - 10 times;
• We do the exercise in the same way as in the previous description, but the middle and index fingers are involved. Repeat the exercise - 10 times;
• We unclench and compress various objects. One approach - 10 times.

Therapeutic exercises and massage contribute to a faster recovery of the motor function of the upper shoulder girdle.

Table of contents of the subject "Back area of ​​a shoulder. Anterior elbow area. Back elbow area.":
1. Back area of ​​the shoulder. External landmarks of the posterior region of the shoulder. Borders of the back region of the shoulder. Projection on the skin of the main neurovascular formations of the posterior region of the shoulder.
2. Layers of the back of the shoulder. Posterior fascial bed of the shoulder. Own fascia of the shoulder.
3. Topography of the neurovascular bundle of the posterior region of the shoulder. Topography of the radial nerve (n. radialis). Connection of fiber in the posterior region of the shoulder with neighboring regions.
4. Anterior elbow area. External landmarks of the anterior ulnar region. Borders of the anterior elbow region. Projection on the skin of the main neurovascular formations of the anterior ulnar region.
5. Layers of the anterior elbow region. Veins of the elbow region. Topography of superficial (subcutaneous) formations of the anterior elbow region.
6. Own fascia of the anterior elbow region. Pirogov's muscle. Fascial beds of the anterior ulnar region.
7. Topography of the neurovascular formations of the anterior elbow region. Topography of deep (subfascial) formations of the anterior ulnar region.
8. Back elbow area. External landmarks of the posterior ulnar region. Borders of the posterior elbow region. Projection on the skin of the main neurovascular formations of the posterior ulnar region.
9. Layers of the posterior elbow area. Synovial bag of the olecranon. Topography of the neurovascular formations of the posterior elbow region. Topography of the posterior elbow region.

Topography of the neurovascular bundle of the posterior region of the shoulder. Topography of the radial nerve (n. radialis). Connection of fiber in the posterior region of the shoulder with neighboring regions.

radial nerve comes to the back surface of the shoulder from the anterior fascial bed through the gap between the long and lateral heads of the triceps muscle. Further, it is located in the brachial canal, canalis humeromuscularis, which spirally envelops the humerus in its middle third. One wall of the canal is formed by a bone, the other by the lateral head of the triceps muscle (Fig. 3.18).

In the middle third of the shoulder canalis humeromuscularis radial nerve adjoins directly to the bone, which explains the occurrence of paresis or paralysis after the application of a hemostatic tourniquet on the middle of the shoulder for a long time or in cases of damage due to fractures of the diaphysis of the humerus.

Together with the nerve goes the deep artery of the shoulder, a. profunda brachii, which soon after the onset gives off an important for collateral circulation between the areas of the shoulder girdle and shoulder ramus deltoi-deus, anastomosing with the deltoid branch of the thoracoacromial artery and with the arteries that envelop the humerus. In the middle third of the shoulder a. profunda brachii is divided into two terminal branches: a. collateralis radialis and a. collateralis media. The radial nerve together with a. collateralis radialis on the border of the middle and lower third of the region perforates the lateral intermuscular septum and returns to the anterior shoulder bed, and then to the anterior ulnar region. There the artery anastomoses with a. recurrens radialis. A. collateralis media anastomoses with a. interossea recurrences.

In the lower third of the shoulder in the posterior fascial bed passes the ulnar nerve with a. collateralis ulnaris superior. Then they go to the back of the elbow area.

Rice. 3.18. Back of the shoulder 1 - m. infraspinatus; 2 - m. teres minor; 3 - m. teres major, 4 - a. brachialis; 5-r. muscularis a. profundae brachii; 6 - n. cutaneus brachii medialis; 7 - m. triceps brachii (caput longum); 8-r. muscularis n. radialis; 9 - m. triceps brachii (caput laterale); 10 - m. triceps brachii (caput mediale); 11 - tendo m. tricipitis brachii; 12-n. ulnaris et a. collateralis ulnaris superior, 13 - n. cutaneus antebrachii posterior; 14-a. collateralis media; 15 - m. anconeus; 16 - m. flexor carpi ulnaris; 17 - m. trapezius; 18 - spina scapulae; 19 - m. deltoideus; 20-n. axillaris et a. circumflexa humeri posterior, 21 - a. cicumflexa scapulae; 22 - humerus; 23-n. radialis et a. profunda brachii.

Communication of fiber in the posterior region of the shoulder with neighboring regions

1. Along the course of the radial nerve proximally, the fiber is connected with the fiber of the anterior fascial bed of the shoulder.

2. Distally- with fiber of the cubital fossa.

3. along the long head of the triceps brachii it is associated with the fiber of the axillary fossa.

Educational video of the anatomy of the axillary, brachial arteries and their branches

The radial nerve is formed from the posterior bundle of the brachial plexus and is a derivative of the ventral branches of the CV - CVIII spinal nerves. Along the back wall of the armpit, the nerve descends, being behind the axillary artery and located sequentially on the abdomen subscapularis and on tendons latissimus dorsi back and teres major muscle. Having reached the brachio-muscular angle between the inner part of the shoulder and the lower edge of the posterior wall of the armpit, the radial nerve is adjacent to the dense connective tissue ribbon formed by the connection of the lower edge of the latissimus dorsi muscle and the posterior tendon part of the long head of the triceps brachii muscle. Here is a place of possible, especially external, compression of the radial nerve. Further, the nerve lies directly on the humerus in the groove of the radial nerve, otherwise called the spiral groove. This groove is limited by the places of attachment to the bone of the external and internal heads of the triceps muscle of the shoulder. This forms the canal of the radial nerve, also called the spiral, brachioradial or brachiomuscular canal. In it, the nerve describes a spiral around the humerus, passing from the inside and posteriorly in the anterior-outer direction. The spiral canal is the second site of potential compression of the radial nerve. From it on the shoulder, branches approach the triceps muscle of the shoulder and the ulnar muscle. These muscles extend the upper limb at the elbow joint.

A test to determine their sips: the subject is asked to unbend a limb that is slightly bent at the elbow joint; the examiner resists this movement and palpates the contracted muscle.

The radial nerve at the level of the outer edge of the shoulder at the border of the middle and lower thirds of the shoulder changes the direction of its course, turns in front, pierces the external intermuscular septum, passing into the anterior compartment of the shoulder. Here the nerve is especially vulnerable to compression. Below, the nerve passes through the initial part of the brachioradialis muscle: it innervates it and the long radial extensor of the hand and descends between it and the brachialis muscle.

The brachioradialis muscle (innervated by the CV - CVII segment) flexes the upper limb at the elbow joint and pronates the forearm from the supination position to the median position.

Test to determine her sips: the subject is asked to bend the limb at the elbow joint and at the same time pronate the forearm from the supination position to the middle position between supination and pronation; the examiner resists this movement and palpates the contracted muscle.

The long radial extensor of the hand (innervated by the segment CV - CVII) unbends and abducts the hand.

Test to determine the strength of the muscle: offer to unbend and abduct the brush; the examiner resists this movement and palpates the contracted muscle. Having passed shoulder muscle, the radial nerve crosses the capsule of the elbow joint and approaches the supinator. In the ulnar region at the level of the external epicondyle of the shoulder or a few centimeters above or below it, the main trunk of the radial nerve is divided into superficial and deep branches. The superficial branch runs through the brachioradialis muscle on the forearm. In its upper third, the nerve is located outward from the radial artery and above the styloid process of the beam passes through the gap between the bone and tendon of the brachioradialis muscle to the dorsum of the lower end of the forearm. Here, this branch is divided into five dorsal digital nerves (nn. Digitales dorsales). The latter branch in the radial half of the dorsal surface of the hand from the nail phalanx I, middle phalanx II and the radial half of the III fingers.

The deep branch of the radial nerve enters the gap between the superficial and deep bundles of the supinator and is directed to the dorsal surface of the forearm. The dense fibrous upper edge of the superficial bundle of the supinator is called Froze's arcade. Under the Froze arcade is also the site of the most likely occurrence of radial nerve tunnel syndrome. Passing through the supinator canal, this nerve is adjacent to the neck and body of the radius and then exits to the dorsum of the forearm, under the short and long superficial extensors of the hand and fingers. Before reaching the rear of the forearm, this branch of the radial nerve supplies the following muscles.

1. The short radial extensor of the wrist (innervated by the CV-CVII segment) is involved in the extension of the hand.
2. The supinator (innervated by the CV-CVIII segment) rotates and supinates the forearm.

A test to determine the strength of this muscle: the subject is asked to supinate the limb extended in the elbow joint from the position of pronation; the examiner resists this movement.

On the dorsum of the forearm, the deep branch of the radial nerve innervates the following muscles.

The extensor of the fingers of the hand (innervated by the segment CV - CVIII) unbends the main phalanges of the II V fingers and at the same time the hand.

Test to determine its strength: the subject is asked to unbend the main phalanges of the II - V fingers, when the middle and nail are bent; the examiner resists this movement.

The ulnar extensor of the hand (innervated by segment CVI-CVIII) extends and adducts the hand.

A test to determine its strength: the subject is asked to straighten and bring the hand; the examiner resists this movement and palpates the contracted muscle. The continuation of the deep branch of the radial nerve is the dorsal interosseous nerve of the forearm. It passes between the extensors of the thumb to the wrist joint and sends branches to the following muscles.

The long muscle that abducts the thumb of the hand (innervated by segment CVI - CVIII) abducts the first finger.

A test to determine its strength: the subject is asked to withdraw and slightly straighten his finger; the examiner resists this movement.

The short extensor of the thumb (innervated by segment CVI-CVIII) unbends the main phalanx of the first finger and abducts it.

Test to determine its strength: the subject is asked to straighten the main phalanx of the first finger; the examiner resists this movement and palpates the tense muscle tendon.

The long extensor of the thumb (innervated by segment CVII-C VIII) extends the nail phalanx of the first finger.

Test to determine its strength: the subject is asked to straighten the nail phalanx of the first finger; the examiner resists this movement and palpates the tense muscle tendon.

Extensor index finger(innervated by segment CVII-CVIII) extends the index finger.

Test to determine its strength: the subject is asked to straighten the second finger; the examiner resists this movement.

The extensor of the little finger (innervated by the segment CVI - CVII) unbends the V finger.

Test to determine its strength: the subject is asked to straighten the V finger; the examiner resists this movement.

The posterior interosseous nerve of the forearm also gives off thin sensory branches for the interosseous septum, periosteum of the radius and ulna, rear surface carpal and carpometacarpal joints.

The radial nerve is predominantly motor and supplies mainly the extensor muscles of the forearm, hand, fingers.

To determine the level of damage to the radial nerve, one should know where and how the motor and sensory branches depart from it. The posterior cutaneous nerve of the shoulder branches into the axillary outlet. It supplies the dorsum of the shoulder almost to the olecranon. The posterior cutaneous nerve of the forearm separates from the main nerve trunk at the humeroaxillary angle or in the spiral canal. Regardless of the location of the branch, this branch always passes through the spiral canal, innervating the skin of the posterior surface of the forearm. Branches to the three heads of the triceps muscle of the shoulder depart in the area of ​​​​the axillary fossa, the shoulder-axillary angle and the spiral canal. Branches to the brachioradialis muscle, as a rule, depart below the spiral canal and above the external epicondyle of the shoulder. Branches to the long radial extensor carpi usually depart from the main trunk of the nerve, although below the branches to the previous muscle, but above the supinator. Branches to the extensor carpi radialis brevis may originate from the radial nerve, its superficial or deep branches, but also usually above the entrance to the supinator canal. The nerves to the supinator may branch off above or at the level of this muscle. In any case, at least some of them pass in the channel of the supinator.

Consider the levels of damage to the radial nerve. At the level of the shoulder-axillary angle, the radial nerve and the branches that have departed from it in the axillary fossa to the triceps muscle of the shoulder can be pressed against the dense tendons of the latissimus dorsi and pectoralis major muscle in the tendon angle of the axillary exit area. This angle is limited by the tendons of these two muscles and the long head of the triceps brachii. Here, external compression of the nerve can occur, for example, due to incorrect use of the crutch - the so-called "crutch" paralysis. The nerve may also be compressed by the back of a chair in office workers or by the edge of an operating table over which the shoulder hangs during surgery. Known compression of this nerve implanted under the skin chest driver heart rate. Internal compression of the nerve at this level occurs with fractures of the upper third of the shoulder. Symptoms of damage to the radial nerve at this level are distinguished primarily by the presence of hypesthesia on the back of the shoulder, to a lesser extent by the weakness of extension of the forearm, as well as the absence or decrease in the reflex from the triceps muscle of the shoulder. When pulling the upper limbs forward to the horizontal line, a “hanging or falling hand” is revealed - a consequence of paresis of the extension of the hand in the wrist joint and II-V fingers in the metacarpophalangeal joints.

In addition, there is weakness in extension and abduction of the first finger. Supination of the extended upper limb also fails, whereas with preliminary flexion in the elbow joint, supination is possible due to the biceps muscle. Flexion at the elbow pronation of the upper limb is impossible due to paralysis of the brachioradialis muscle. Hypotrophy of the muscles of the dorsum of the shoulder and forearm can be detected. The hypesthesia zone captures, in addition to the back surface of the shoulder and forearm, the outer half of the back surface of the hand and the first finger, as well as the main phalanges of the II and radial half of the third finger. Compression lesion of the radial nerve in the spiral canal is usually the result of a fracture of the shoulder in the middle third. Nerve compression may occur shortly after a fracture due to tissue swelling and increased pressure in the canal. Later, the nerve suffers when it is compressed by scar tissue or callus. With spiral channel syndrome, there is no hypoesthesia on the shoulder. Usually does not suffer triceps shoulder, since the branch to it is located more superficially - between the lateral and medial heads of this muscle - it is not directly attached to the bone. In this tunnel, the radial nerve moves along the long axis of the humerus during the contraction of the triceps muscle. The callus formed after a shoulder fracture can prevent such nerve movements during muscle contraction and thereby contribute to its friction and compression. This explains the occurrence of pain and paresthesia on the dorsum of the upper limb during extension in the elbow joint against the resistance force for 1 min with incomplete post-traumatic damage to the radial nerve. Painful sensations can also be caused by finger pressure for 1 minute or by tapping the nerve at the level of compression. The rest of the symptoms are similar to those observed with damage to the radial nerve in the region of the shoulder-axillary angle.

At the level of the external intermuscular septum of the shoulder, the nerve is relatively fixed. This is the site of the most common and simplest compression lesion of the radial nerve. It is easily pressed against the outer edge of the radius during deep sleep on a hard surface (gloss, bench), especially if the head is pressing on the shoulder. Due to fatigue, and more often able alcohol intoxication a person does not wake up in time, and the function of the radial nerve is turned off (“sleepy”, paralysis, “garden bench paralysis”). With "sleep paralysis" there are always motor losses, but there is never weakness of the triceps muscle of the shoulder, that is, paresis of the extension of the forearm and a decrease in the reflex from the triceps muscle of the shoulder. Some patients may experience loss of not only motor functions, but also sensitive ones, however, the zone of hypesthesia does not extend to the back surface of the shoulder.

In the lower third of the shoulder above the external epicondyle, the radial nerve is covered by the brachioradialis muscle. Here, the nerve can also be compressed with fractures of the lower third of the humerus or with displacement of the head of the radius.

Symptoms of damage to the radial nerve in the supracondylar region may be similar to "sleep paralysis". However, in the nervous case, no isolated loss of motor functions without sensory ones is observed. The mechanisms of occurrence of these types of compression neuropathies are also different. The level of compression of the nerve approximately coincides with the site of the shoulder fracture. In differential diagnosis, the determination of the upper level of provoking pain on the back surface of the forearm and hand also helps with tapping and finger compression along the projection of the nerve.

In some cases, it is possible to determine the compression of the radial nerve by the fibrous arch of the lateral head m. triceps. The clinical picture corresponds to the above. Pain and numbness on the back of the hand in the zone of supply of the radial nerve can periodically increase with intensive manual work, while running on long distances, with a sharp flexion of the upper limbs in the elbow joint. This causes compression of the nerve between the humerus and the triceps muscle of the shoulder. Such patients are advised to pay attention to the angle of flexion in the elbow joint when running, to stop manual labor.

A fairly common cause of damage to the deep branch of the radial nerve in the area of ​​​​the elbow joint and the upper suit of the forearm is compression of its lipoma, fibroma. They are usually palpable. Removal of the tumor usually leads to recovery.

Among other causes of damage to the branches of the radial nerve, mention should be made of bursitis and synovitis of the elbow joint, especially in patients with rheumatoid arthritis, fracture of the proximal head of the radius, traumatic vascular aneurysm, professional overstrain with repetitive rotational movements of the forearm (conducting, etc.). Most often, the nerve is affected in the canal of the supinator fascia. Less commonly, it occurs at the level of the elbow joint (from the passage of the radial nerve between the brachial and brachioradialis muscles to the head of the radius and long radial flexor carpi), which is referred to as radial tunnel syndrome. The cause of compression-ischemic nerve damage can be a fibrous band in front of the head of the radius, dense tendon edges of the short radial extensor of the wrist, or Froze's arcade.

The supinator syndrome develops with damage to the posterior interosseous nerve in the region of Froze's arcade. It is characterized by night pains in the outer sections of the elbow region, on the back of the forearm and, often, on the back of the wrist and hand. Daytime pains usually occur during manual work. The rotational movements of the forearm (supination and pronation) are especially conducive to the appearance of pain. Often, patients note weakness in the hand that appears during work. This may be accompanied by a violation of the coordination of movements of the hand and fingers. Local tenderness is found on palpation at a point located 4–5 cm below the external epicondyle of the shoulder in the groove radially to the long radial extensor of the wrist.

Tests are used that cause or increase pain in the arm, for example, a supination test: both palms of the subject are tightly fixed on the table, the forearm is bent at an angle of 45 ° and is set in the position of maximum supination; the examiner tries to move the forearm into a pronation position. This test is performed within 1 min, it is considered positive if during this period pain appears on the extensor side of the forearm.

Extension test of the middle finger: pain in the hand can be caused by prolonged (up to 1 min) extension of the third finger with resistance to extension.

There is a weakness of the supination of the forearm, extension of the main phalanges of the fingers, sometimes there is no extension in the metacarpophalangeal joints. Paresis of the abduction of the first finger is also detected, but the extension of the terminal phalanx of this finger is preserved. With the loss of the function of the short extensor and the long abductor muscle of the thumb, radial abduction of the hand in the plane of the palm becomes impossible. When the wrist is extended, there is a deviation of the hand in the radial direction due to the loss of the function of the ulnar extensor of the wrist, while the long and short radial extensor of the wrist are preserved.

The posterior interosseous nerve can be compressed at the level of the middle or lower part of the supinator by dense connective tissue. In contrast to the "classic" supinator syndrome caused by nerve compression in the region of Froze's arcade, in the latter case, the symptom of digital compression is positive at the level of not the upper, but the lower edge of the muscle. In addition, paresis of the extension of the fingers in the "lower arch support syndrome" is not combined with weakness of the supination of the forearm.

The superficial branches of the radial nerve at the level of the lower forearm and wrist can be squeezed by a tight watch strap or handcuffs ("prisoner's paralysis"). However, the most common cause of nerve damage is injury to the wrist and lower third of the forearm.

Compression of the superficial branch of the radial nerve in a fracture of the lower end of the radius is known as Turner's syndrome, and damage to the branches of the radial nerve in the anatomical snuffbox is called radial carpal tunnel syndrome. Compression of this branch is a common complication of de Quervain's disease (ligamentitis of the I canal of the dorsal carpal ligament). A short extensor muscle and a long abductor muscle of the first finger pass through this canal.

With damage to the superficial branch of the radial nerve, patients often feel numbness on the back of the hand and fingers; sometimes there is a burning pain on the back of the first finger. The pain can spread to the forearm and even to the shoulder. In the literature, this syndrome is called Wartenberg's paresthetic neuralgia. Sensitive prolapses are often limited to a hypesthesia track on the inner back of the first finger. Often, hypoesthesia can extend beyond the I finger to the proximal phalanges of the II finger and even to the rear of the main and middle phalanges of the III and IV fingers.

Sometimes the superficial branch of the radial nerve thickens at the wrist. Finger compression of such a "pseudo-neuroma" causes pain. The symptom of tapping is also positive when tapping along the course of the radial nerve at the level of the anatomical snuffbox or the styloid process of the radius.

The differential diagnosis of damage to the radial nerve is carried out with spinal root syndrome CVII, in which, in addition to weakness of extension of the forearm and hand, paresis of adduction of the shoulder and flexion of the hand is detected. If motor loss is absent, the localization of pain should be considered. With damage to the CVII root, pain is felt not only on the hand, but also on the dorsum of the forearm, which is not typical for damage to the radial nerve. In addition, radicular pain is provoked by head movements, sneezing, coughing.

For syndromes of the level of the thoracic outlet, the occurrence or intensification of pain in the arm when the head is turned to the healthy side, as well as when performing some other specific tests, is characteristic. At the same time, the pulse on the radial artery may decrease at the same time. It should also be taken into account that if at the level of the thoracic outlet the part of the brachial plexus corresponding to the CVII root is compressed, then a picture similar to the lesion of this root described above arises.

To determine the level of damage to the radial nerve helps electroneuromyography. You can limit yourself to a study using needle electrodes of the triceps muscle of the shoulder, brachioradialis muscle, extensor of the fingers and extensor of the index finger. In supinator syndrome, the first two muscles will be preserved, and in the last two, during their complete voluntary relaxation, spontaneous (denervation) activity can be detected in the form of fibrillation potentials and positive sharp waves, as well as with maximum voluntary muscle tension - the absence or slowdown of potentials motor units. When the radial nerve is stimulated on the shoulder, the amplitude of the muscle action potential from the extensor of the index finger is significantly lower than when the nerve is electrically stimulated below the supinator canal on the forearm. Establishing the level of damage to the radial nerve can also help the study of latent periods - the time of the nerve impulse and the speed of propagation of excitation along the nerve. To determine the speed of propagation of excitation along the motor fibers of the turbid nerve, electrical stimulation is performed in various points. by the most high level irritation is the Botkin-Erb point, located a few centimeters above the collarbone in the posterior triangle of the neck, between the posterior edge of the sternocleidomastoid muscle and the clavicle. Below, the radial nerve is irritated at the point of exit from the axillary fossa in the groove between the coracobrachial muscle and the posterior edge of the triceps muscle of the shoulder, in the spiral groove at the level of the middle of the shoulder, and also at the border between the lower and middle third of the shoulder, where the nerve passes through the intermuscular septum, even more distally - 5 - 6 cm above the external epicondyle of the shoulder, at the level of the elbow (shoulder) joint, on the back of the forearm 8 - 10 cm above the wrist or 8 cm above the styloid process of the beam. Recording electrodes (usually concentric needle-shaped) are inserted at the site of maximum response to stimulation of the nerve of the triceps muscle - shoulder, brachial, brachioradialis, extensor of the fingers, extensor of the index finger, long extensor of the thumb, long abductor muscle or short extensor of the thumb. Despite some differences in the points of stimulation of the nerve and the places of registration of the muscular response, normally, close values ​​of the rate of propagation of excitation along the nerve are obtained. Its lower limit for the "neck-armpit" section is 66.5 m/s. On a long section from the supraclavicular point of Botkin-Erb to the lower third of the shoulder average speed sometimes 68-76 m / s. In the section “axillary fossa - 6 cm above the external epicondyle of the shoulder”, the speed of propagation of excitation is on average 69 m / s, and in the section “6 cm above the external epicondyle of the shoulder - forearm 8 cm above the styloid process of the beam" - 62 m / s at abduction of muscle potential from the extensor of the index finger. From this it can be seen that the speed of propagation of excitation along the motor fibers of the radial nerve on the shoulder is approximately 10% higher than on the forearm. The average values ​​on the forearm are 58.4 m/s (fluctuations are from 45.4 to 82.5 m/s). Since lesions of the radial nerve are usually unilateral, taking into account individual differences in the speed of propagation of excitation along the nerve, it is recommended to compare the indicators on the diseased and healthy sides. By examining the speed and time of nerve impulse conduction starting from the neck and ending with various muscles innervated by the radial first, it is possible to differentiate the pathology of the plexus and various levels of nerve damage. Lesions of the deep and superficial branches of the radial nerve are easily distinguished. In the first case, only pain in the upper limb occurs and motor loss can be detected, and superficial sensitivity is not disturbed.

In the second case, not only pains are felt, but also paresthesias, there are no motor prolapses, but superficial sensitivity is disturbed.

It is necessary to differentiate the compression of the superficial branch in the ulnar region from its involvement at the level of the wrist or the lower third of the forearm. The zone of painful sensations and sensitive fallout may be the same. However, the voluntary forced wrist extension test will be positive if the superficial branch is compressed only at the proximal level when passing through the extensor carpi radialis brevis. You should also carry out tests with tapping or finger compression along the projection of the superficial branch. The upper level, at which, under these influences, paresthesias are caused on the back of the hand and fingers, is a probable place of compression of this branch. Finally, the level of nerve damage can be determined by injecting 2-5 ml of a 1% solution of novocaine or 25 mg of hydrocortisone into this place, which leads to a temporary cessation of pain and / or paresthesia. If the blockade of the nerve is performed below the place of its compression, the intensity of pain will not change. Naturally, it is possible to temporarily relieve pain by blocking the nerve not only at the level of compression, but also above it. To distinguish between the distal and proximal lesions of the superficial branch, 5 ml of a 1% solution of novocaine is first injected at the border of the middle and lower thirds of the forearm at its outer edge. If the blockade is effective, this indicates a lower level of neuropathy. If there is no effect, a second blockade is performed, but already in the area of ​​​​the elbow joint, which relieves pain and indicates the upper level of damage to the superficial branch of the radial nerve.

Diagnosis of the place of compression of the superficial branch can also be helped by the study of the spread of excitation along the sensory fibers of the radial nerve. The conduction of a nerve impulse along them is completely or partially blocked at the level of compression of the superficial branch. With partial blockade, the time and speed of propagation of excitation along sensitive nerve fibers slow down. Various research methods are used. With the orthodromic technique, excitation along the sensitive fibers propagates towards the conduction of the sensitive impulse. To do this, irritating electrodes are placed on the limb more distally than the discharge electrodes. With the antidromic method, the spread of excitation along the fibers in the opposite direction is fixed - from the center to the periphery. In this case, the electrodes located proximally on the limb are used as irritants, and the distal electrodes are used as discharge electrodes. The disadvantage of the orthodromic technique, in comparison with the antidromic one, is that the first one registers lower potentials (up to 3–5 μV), which can be within the noise of the electromyograph. Therefore, the antidromic technique is considered to be more preferable.

The most distal electrode (irritating in the orthodromic and abducting - in the antidromic technique) is best applied not to the back surface of the first finger. and in the area of ​​the anatomical snuffbox, approximately 3 cm below the styloid process, where a branch of the superficial branch of the radial nerve passes over the tendon of the long extensor of the thumb. In this case, the response amplitude is not only higher, but also subject to smaller individual fluctuations. The same advantages have the imposition of a distal electrode not on the I finger, but on the gap between the I and II metatarsal bones. The average speed of propagation of excitation along the sensitive fibers of the radial nerve in the area from the leaf electrodes to the lower parts of the forearm in the orthodromic and antidromic directions is 55-66 m/s. Despite individual fluctuations, the rate of propagation of excitation along the symmetrical sections of the nerves of the extremities in individuals on both sides is approximately the same. Therefore, it is not difficult to detect a slowdown in the rate of propagation of excitation along the fibers of the superficial branch of the radial nerve in its unilateral lesion. The speed of propagation of excitation along the sensory fibers of the radial nerve is somewhat different in certain areas: from the spiral groove to the ulnar region -77 m/s, from the ulnar region to the middle of the forearm - 61.5 m/s, from the middle of the forearm to the wrist - 65 m/s , from the spiral groove to the middle of the forearm - 65.7 m/s, from the elbow to the wrist - 62.1 m/s, from the spiral groove to the wrist - 65.9 m/s. A significant slowdown in the rate of propagation of excitation along the sensory fibers of the radial nerve in its two upper segments will indicate a proximal level of neuropathy. Similarly, the distal level of the lesion of the superficial branch can be detected.

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Superficial veins: lateral saphenous vein of the arm. medial saphenous vein of the arm. "M".-shaped type of anastomosis. - intermediate medial saphenous vein,. intermediate lateral saphenous vein. "I".-shaped type of anastomosis - intermediate vein of the elbow ..

Superficial nerves: medial cutaneous nerve of the forearm. lateral cutaneous nerve of the forearm.

Venepuncture: Venesection: is performed if long-term infusions are necessary when venipuncture is impossible, .1 moment - vein isolation, .2 moment - ligatures under the allocated vein,. 3rd moment - dissection of the anterior wall of the vein and its catheterization. after which the proximal ligature is tied on the catheter. and the peripheral end of the vein is tied with a distal ligature. 4th moment - suturing the wound with interrupted silk sutures ..

TOPOGRAPHY OF THE RADIAL NEVER

radial nerve shoulder, together with the deep artery of the shoulder and its branches, along the upper and middle third of the shoulder, is located in a spiral canal. this canal is formed in front by the furrow of the radial nerve of the humerus. behind - the triceps muscle of the shoulder,. The proximity of the radial nerve of the shoulder to the bone explains its damage by bone fragments during a fracture or its involvement in the callus. paralysis and paresis can be observed when a hemostatic tourniquet is applied. especially when applied in the middle third,. because here the nerve is most closely in contact with the bone. therefore, the tourniquet is correctly applied in the upper third of the shoulder. where the contact of the radial nerve and the humerus is less pronounced.

The radial nerve on the border with the axillary fossa lies behind the brachial artery, then passes between the long and medial heads of the triceps muscle into the spiral canal. Having rounded the bone in the lower third of the shoulder, the nerve appears on its outer surface between the brachial and brachioradialis muscles. Innervates the triceps muscle, brachioradialis and gives skin branches to the back surface of the shoulder and forearm. Projection line - from the middle of the rear edge deltoid muscle to the lower end of the lateral groove of the biceps muscle.

TOPOGRAPHY OF THE ULCAN NERVE

Ulnar nerve

The ulnar nerve passes into the ulnar groove from the posterior ulnar region between the heads of the ulnar flexor of the wrist, it gives motor branches to this muscle and to the ulnar part of the deep flexor of the fingers. In the middle third of the forearm, the ulnar branch and the dorsal branch depart from the ulnar nerve, which deviates inwards, passes between the ulna and the ulnar flexor of the wrist, pierces its own fascia of the forearm and, at the border with the wrist, passes to the rear of the hand

TOPOGRAPHY OF THE MEDIAN NERVE

In the upper third of the forearm, the nerve lies between the heads of the round pronator, crosses ulnar artery in front, passes between the superficial and deep flexors of the fingers and in the lower third reaches the median sulcus. The median nerve supplies motor branches to the round pronator, radial flexor wrist, long palmar muscle, superficial flexor of the fingers, radial part of the deep flexor of the fingers, long flexor of the first finger, gives off the anterior interosseous nerve and cutaneous palmar cord.

median nerve lies in the canalis carpalis along with the tendons of the superficial and deep flexors of the p-tsev and m.flexor pollicis longus. Its branches nah-Xia under the PLD, next to it nah-Xia palmar branches n.ulnaris. From them depart nn.digitales palmares communes, to-rye affairs on their own. digital nerves (those exit. h-z KO to the fingers).

The “forbidden zone” is a place of retreat. from the median nerve of the branch to the muscle of the tenar (projected onto the prox. half of the tenar).

In lat. side goes superficial palmar branch a.radialis. For honey. side go elbow. s-dy and nerves (in canalis carpi ulnaris).

In fiber under LA nah-Xia superficial palmar arch (arr-Xia at the expense of a.ulnaris, edges anastomoses with the surface of the palmar branch of a.radialis) - lies in the middle of the 3rd metacarpal bone. 3 aa.digitales palmares co-mmunes depart from it, to-rye, having left through the KO, anastomy with the metacarpal arteries (from the GLD) and divide into their own digital arteries (which supply The sides of 2-5 fingers facing each other are located. .

Deep palmar arch lies proximal to the PLD on the interosseous muscles under the flexor tendons (separated from them by fiber and deep fascia). Obr-Xia at the expense of a.radialis, edge anastast with a deep palmar branch a.ulna-ris. Aa.metetarseae palmares depart from the arc (which then anastomize with the same dorsal ones and flow into aa.digitales palmares communes

In the neurology of "mononeuropathies", one of the main problems is the problem of determining the "level of nerve damage", since an adequate clinical and expert assessment of the severity of the disease and its prognosis, as well as an adequate development of therapeutic and preventive measures, depend on the "adequacy of its solution". Consider the basic principles of the "level" diagnosis of neuropathy on the example of the radial nerve (n. Radialis). It should first be noted that the "level" diagnosis of neuropathy is appropriate only in the absence of clear indications of the level of exposure to an exogenous provoking factor (for example, a fracture of the "beam in a typical place" or a fracture of the humerus at the level of its c/3), which requires identification the level of nerve pathology according to the basic principles of topical diagnostics in neurology (in particular, according to the "level principle"), as well as in the differential diagnosis of the causes limiting one or another action in the limb - pathology of the musculoskeletal system or "purely neurogenic" cause (for example, pathology of the superficial branch of the radial nerve in case of a fracture of the radius in the n / c, i.e. in case of a fracture of the radius in a "typical place" will never cause limitation of extension of the hand and fingers, but will only cause pathological deficient or irritative phenomena). Before proceeding to the level diagnostics (and its principles) of the pathology of the radial nerve, it is necessary, firstly, to consider the course of the radial nerve and its main (“ramus”) dichotomies, and secondly, to consider the muscles and skin areas that the radial nerve innervates, and thirdly, to correlate the first with the second, then determine at what level which muscles and skin areas are innervated by the radial nerve (its branches).

course of the radial nerve : the radial nerve is formed from the [secondary] posterior brachial plexus and is a derivative of the ventral branches of the CV - CVIII spinal nerves; along the posterior armpit, the nerve descends, being the axillary artery and located sequentially on the abdomen of the subscapularis muscle, on the tendons of the latissimus dorsi and the large round muscle; having reached the shoulder-axillary angle between the inner part of the shoulder and the lower edge of the posterior wall of the armpit, the radial nerve is adjacent to a dense connective tissue ribbon formed by the connection of the lower edge of the latissimus dorsi muscle and the posterior tendon part of the long head of the triceps brachii muscle (in the region of the exit of the radial nerve from the axillary fossa from its the main trunk departs the posterior cutaneous nerve of the shoulder); further, the nerve lies directly on the humerus and the groove of the radial nerve, otherwise called "[gutter]", in this channel the nerve describes a spiral around the humerus, passing from the inside and posteriorly in the anterolateral direction; further, the nerve at the level of the outer edge of the shoulder at the border of the middle and lower third of the shoulder changes the direction of its course, turns forward and pierces the external intermuscular septum, passing into the anterior compartment of the shoulder; below, the nerve passes through the initial part of the brachioradialis muscle and descends between it and the brachialis muscle; having passed the shoulder muscle, the radial nerve crosses the capsule of the elbow joint and passes to the arch support; in the ulnar region at the level of the external epicondyle of the shoulder or a few centimeters above or below it, the main trunk of the radial nerve into the superficial and deep branches; the superficial branch goes under the brachioradialis muscle on the forearm; in its upper third, the nerve is located outward from the radial artery, passes through the gap between the bone and the tendon of the brachioradialis muscle to the back of the lower end of the forearm; here this branch is divided into five dorsal digital nerves (nn. digitales dorsales); the latter branch in the radial half of the dorsum of the hand from the nail phalanx I, middle phalanx II and the radial half of the III fingers; the branch of the radial nerve enters the gap between the superficial and deep bundles of the supinator and is directed to the dorsum of the forearm (the dense fibrous upper edge of the superficial bundle of the supinator is called Froze's arcade); penetrating through the instep canal, the deep branch of the radial nerve is adjacent to the neck and body of the radius and then exits to the dorsum of the forearm, under the short and long superficial extensors of the hand and fingers. The continuation of the deep branch of the radial nerve is the dorsal (posterior) interosseous nerve of the forearm - it passes between the extensors of the thumb to the wrist joint. Thus, four most important (from a clinical point of view) parts of the radial nerve can be distinguished: 1. main trunk (motor and sensory function) - at the level of the humerus, 2. superficial branch (sensory function), 3. internal branch (motor function ) and its continuation - 4. posterior (dorsal) interosseous nerve (motor and sensory function).

Muscles innervated by the radial nerve: 1. triceps muscle of the shoulder, ulnar muscle(their innervation - during the passage of the radial nerve in the axillary fossa, at the level of the shoulder-axillary angle and in the spiral canal); 2. brachioradialis muscle, long radial extensor of the hand (their innervation is at the level of the lower third of the humerus, after the nerve passes through the external intermuscular septum); 3. short radial extensor of the wrist, arch support (their innervation is at the level of the upper part of the upper third of the forearm); 4. extensor of the fingers of the hand [main phalanges], ulnar extensor of the hand (their innervation is at the level of the lower part of the upper third of the forearm); 5. Further, the innervation of the muscles is carried out by the dorsal (posterior) interosseous nerve: longus muscle abductor thumb, short extensor of the thumb, long extensor of the thumb, extensor of the index finger, extensor of the little finger (their innervation is at the level of the middle third of the humerus, after the nerve passes through the external intermuscular septum).

Sensory innervation: the posterior cutaneous nerve branches off in the area of ​​​​the axillary outlet (supplies the dorsum of the shoulder almost to the olecranon); the posterior cutaneous nerve of the forearm separates from the main nerve trunk in the brachio-axillary angle or in the spiral canal (regardless of the location of the branch, this branch always passes through the spiral canal, innervating the posterior surface of the forearm); at the level of the lower part of the rear of the forearm, the superficial branch is divided into five dorsal digital nerves (nn. digitales dorsales), which innervate the skin of the radial half of the dorsal surface of the hand from the nail phalanx I, the middle phalanx II and the radial half of the III fingers; the posterior (dorsal) interosseous nerve of the forearm gives off thin sensitive branches for the interosseous septum, periosteum of the radius and ulna, the posterior surface of the carpal and carpal joints.

Thus, the radial nerve innervates: the muscles of the posterolateral part of the shoulder, forearm and hand (which extend the shoulder, forearm, hand, fingers of the hand [main phalanges], supinate the forearm and hand, take the hand to the radial and ulnar sides, etc.), the skin of the back of the shoulder , forearms and hands (see diagram), etc.

Depending on the level (height) of the lesion in the syndrome of complete damage to the radial nerve, 8 clinically significant levels of compression can be distinguished:

1. at the level of the upper third of the shoulder (shoulo-axillary angle)	1. the presence of hypoesthesia on the posterior surface of the shoulder, forearm, radial half of the dorsum of the hand from the nail phalanx I, middle phalanx II and the radial half of the III fingers; 2. weakness of forearm extension; 3. absence (decrease) of the reflex from the triceps muscle of the shoulder; 4. when stretching the arms forward to the horizontal line, a “hanging” or “falling” hand is revealed (paresis of the extensors of the hand and extensors of the II - V fingers in the metacarpophalangeal joints); 5. weakness of extension and abduction of the first finger; 6. lack of supination of the arm extended at the elbow joint; 7. impossibility of bending at the elbow of the pronated arm (paralysis of the brachioradialis muscle); 8. hypotrophy of the muscles of the dorsal surface of the shoulder and forearm (in case of a long-term lesion);
2. at the level of the middle third of the shoulder (in spiral channel)	the clinic corresponds to the syndrome of the radial nerve at the level of the humeroaxillary angle with the exception of: 1. there is no hypoesthesia on the shoulder; 2. the triceps muscle does not suffer; 3. Pain and paresthesia appear on the dorsum of the arm when the elbow is extended against the resistance force for 1 minute or when the nerve is tapped at the level of compression;
3. at the level of the external intermuscular septum of the shoulder (most common compression site):	see point 2
4. at the level of the lower third of the shoulder (above the external epicondyle):	see point 2
5. at the level of the elbow joint and the upper part of the forearm (most often in the feces of the supinator fascia, in the region of the Froze arcade):	1. the presence of night pains in the outer sections of the elbow region, on the back of the forearm, sometimes on the back of the wrist and hand; 2. the appearance of daytime pain during manual work (especially rotational movements of the forearm - supination and pronation); 3. the presence of weakness in the hand, which appears during manual work; 4. local pain on palpation at a point 4-5 cm below the external epicondyle of the shoulder; 5. positive data of the “supination test” (if pain appears on the extensor side of the forearm within 1 minute); 6. positive test of extension of the middle finger (appearance of pain in the hand with prolonged - up to 1 min - extension of the third finger with resistance to its extension); 7. weakness of supination of the forearm; 8. weakness or lack of extension of the main phalanges of the fingers; 9. weakness of abduction of the first finger (while maintaining the extension of the terminal phalanx of this finger); 10. impossibility of radial abduction of the hand in the plane of the palm; 11. deviation of the hand in the radial direction with an extended wrist;
6. at the level of the middle or lower part of the instep:	1. (unlike item 5) digital compression syndrome is detected at the level of the lower edge of the arch support (and not the upper one); 2. paresis of the extensors of the fingers is not combined with weakness of the arch support of the forearm;
7. at the level of the lower part of the forearm and at the level of the wrist:	1. numbness on the back of the hand and I - III fingers; 2. sometimes burning pain on the back of the fingers; 3. positive "impact symptom" when tapping along the radial nerve at the level of the styloid process of the radius; 4. sometimes the presence of a thickening of the superficial branch of the radial nerve in the wrist area - the appearance of a "pseudo-neuroma", the digital compression of which causes pain;
8. at the level of the anatomical snuffbox (for example, in de Quervain's disease):	1. violation of sensitivity in the autonomous zone of the anatomical snuffbox; 2. violation of the abduction of the first finger; 3. weakness of extension of the first finger; 4. positive "tapping symptom" along the branches of the radial nerve at the level of the anatomical snuffbox.