The median nerve of the hand. The nervous system of the arms and hands. Study of nerve conduction

Reasons for the formation of hand deformities when nerves are damaged.

Damage to the peripheral nerves of the upper limb, in addition to impaired sensitivity and vegetative-trophic functions, leads to movement disorders due to flaccid paralysis of the muscles innervated by the motor branches of these nerves. Despite the undertaken nerve restoration, movement disorders can remain persistent and cause neurogenic deformities and contractures of the fingers.

Within 4-6 months, a denervation process begins in the own muscles of the hand, with the replacement of myofibrils with adipose fibrous connective tissue. The ability of muscles to reinnervation is lost, despite the restoration of peripheral nerve trunks using careful microsurgical techniques. According to leading experts, changes in both muscles and peripheral nerves... In the muscles of a person after damage to tendons and nerves, atrophy, homogenization, fragmentation, a decrease in the number of mitochondria, and a sharp decrease in the content of glycogen were found already by 4-16 days. The motor terminal plates are atrophic; typical Wallerian degeneration is noted in the motor neurons.

With persistent damage to the radial nerve, paralysis of the extensor muscles of the hand and fingers develops. There is no active extension of the hand, fingers and abduction of 1 finger. The hand hangs in the flexion position; active extension of the fingers of the hand is impossible.

The median nerve from the distal third of the forearm carries out motor innervation I-II vermiform muscles, as well as the muscles of the opposing, short abductor and superficial head of the short flexor of the first finger. Own muscles of the hand, due to denervation, quickly undergo atrophy and fibrosis. In this regard, movement disorders in 70-75% of cases remain persistent, causing the formation of neurogenic deformities of the hand and fingers.

The worm-like muscles perform flexion and radial abduction of the proximal phalanges of the II-III fingers and participate in extension in the interphalangeal joints. With paralysis of the I-II vermiform muscles, active flexion and radial abduction of the proximal and extension of the middle and distal phalanges of the II-III fingers are lost. Hyperextension of the proximal phalanges of the II and partly of the III toe develops.

With paralysis of the thenar muscle group, innervated by the median nerve, a very important function is disturbed - the opposition of the first finger. This movement of the first finger is carried out by nine muscles.

Each thenar muscle, innervated by the median nerve, reproduces its inherent function. The short abductor performs a palmar abduction of the first finger with moderate flexion of the main and extension of the distal phalanges. The flexor short flexor flexes the proximal metacarpal bone and unbends the distal phalanx of the first toe. The muscle opposing the 1st finger produces palmar stabilization, flexion and pronation of the 1st metacarpal bone, participating in the opposition of the 1st finger to the II-V fingers.

With persistent damage to the median nerve, the function of these muscles is lost and neurogenic deformity of the metacarpophalangeal joint develops with a 50-60% limitation of the palmar abduction. The first finger in the supination position is in the same plane with respect to the hand with a limitation of radial adduction by 40-50%. Pronation and opposition of the first finger are violated. The ball grip is limited, it is performed by the lateral surface of the finger. The cylindrical grip is partially compensated by the long flexors and extensors of the fingers. The force of the pinched grip is reduced by 30-40%. In connection with the paralysis of the I-II vermiform muscles, hyperextension of the II-III proximal phalanges occurs, exact types of gripping with the fingertips suffer. Not only the function is impaired, but also the shape of the brush.

The ulnar nerve from the distal third of the forearm innervates 14 own muscles of the hand:

deep head of the flexoris short and adductor muscles of the first finger;

abductor, opposing muscles and short flexor of the V finger;

all interosseous muscles;

III-IV worm-like muscles.

The action of the interosseous muscles is extremely diverse: in the metacarpophalangeal joints, they carry out the radial and elbow abduction of the corresponding fingers. The dorsal interosseous muscles flex the proximal phalanges. Palmar interosseous muscles contribute to the extension of the proximal phalanges. III and IV vermiform muscles, starting from the tendons of the deep flexors of the III-IV-V fingers, at the level of the heads of the metacarpal bones pass to the rear of the proximal phalanx and are woven into the extensor tendon apparatus of the corresponding fingers. They flex the proximal phalanges, and when contracted, they pull the deep flexors of the fingers distally, relaxing them, thereby contributing to the extension of the distal phalanges of the fingers.

The interosseous and vermiform muscles of the hand are a kind of regulators of the function of the long flexors and extensors of the fingers, stabilizing and balancing their function.

Thus, with persistent damage to the ulnar nerve, the following components of deformity and limitation of the function of the hand and fingers develop:

atrophy of the ulnar edge of the hand develops;

atrophy and retraction of the intercarpal spaces develop, followed by fibrosis and a screed of the transverse arch of the hand;

the contractile activity of the interosseous muscles is lost, their role as flexors of the proximal and extensors of the middle and distal phalanges of the fingers ceases;

paralysis of the III-IV vermiform muscles is accompanied by the loss of the function of active flexion of the proximal phalanges and extension in the interphalangeal joints of the III-IV-V fingers.

adduction, flexion and pronation of the I finger, flexion, adduction and opposition of the V finger are disturbed;

limited flexion, ulnar and radial abduction of the proximal phalanges, extension of the middle and distal phalanges IV-V and partially III fingers.

With a prolonged stay of the hand in a vicious position, secondary fibrotic changes occur in the tissues of the hand. They form a persistent claw-like deformity, mainly of the ulnar half of the hand with supination of the 1st finger, hyperextension of the proximal phalanges of the III-IV-V fingers, flexion installation of the middle and distal IV-V and partially III fingers; excessive abduction of the V finger.

Elbow flexor of the hand

With persistent damage to the median and ulnar nerves, all own muscles of the hand are turned off from the function, a kind of control panel for coordinating finger movements is lost. There is a hyperextension-flexion deformity of the hand. The longitudinal arch is deformed, the transverse arch becomes flat, the opposition of the first finger disappears. Overextension of the proximal phalanges, flexion contracture in the interphalangeal joints develop. The main types of grip are violated: pinched, ball, interdigital, planar.

Reconstructive surgery for persistent damage to the radial nerve

With paralysis of the muscles of the extensors of the fingers and hand, caused by persistent damage to the radial nerve, produce different options muscle-tendon transpositions. S. Bunnell proposed his own version of muscle movement - the flexor tendon of the hand - to the extensors of the III-V fingers; the radial flexor of the hand - on the extensors of the I-II fingers. I. Matev et al. consider effective transposition of the circular pronator to the radial extensor of the hand, the elbow flexor to the common extensor of the fingers, long palmar muscle- on the short extensor and abductor muscles of the first finger.

A.M. Volkova applies the operation according to Yu.Yu. Dzhanelidze. From the incision along the dorsum of the forearm to the wrist joint, the tendons of the common extensor of the II-V fingers are exposed and long extensor I finger.

From two parallel incisions along the ulnar and radial edges of the distal third of the forearm from the palmar surface, the tendons of the ulnar and radial flexors of the hand are exposed and cut off from the attachment point and transferred through the subcutaneous canals to the dorsum of the forearm. Both wounds on the palmar surface of the forearm are sutured.

The tendon of the extensor longus of the first finger is isolated after dissection of the third osteo-fibrous canal. The hands and fingers are given an extension position.

The elbow flexor of the hand is carried out under the tendons of the common extensor of the fingers and sutured side to side with the tendon of the long extensor of the thumb in the position of maximum extension. All extensor tendons of the II-V fingers are sutured with the radial flexor tendon of the hand.

After suturing the wound, the hand and fingers are fixed with a plaster cast in the position of maximum extension for 5-6 weeks. The described operations in most cases provide a positive functional outcome.

Reconstructive surgery for persistent damage to the median nerve. To date, all methods of reconstructive hand surgery for persistent paralysis of the ulnar and median nerves are divided into:

stabilizing;

dynamic.

During stabilizing operations, a functionally favorable position is created for the fingers to grip objects. During dynamic operations, the active function is restored due to the musculo-tendon transposition of functionally complete muscles.

One of the reasons for the violation of the grasping function in paralysis of the own muscles of the hand is the violation of the opposition of the first finger. To stabilize the first finger in the opposition position, many authors performed arthrodesis of the metacarpal-carpal joint. Synostosis of the I-II metacarpal bones using a bone graft-spacer in the opposition position was performed by Ch. Thompson, B. Boychev et al., R. E. Rae.

Opinion about stabilizing operations is controversial. Currently, they are used very rarely - only in the absence of conditions for muscle-tendon transposition.

There are more than 40 known ways to restore the active opposition of the first finger of the hand with paralysis of the thenar muscles. S. Bunnell performed transposition of the elongated tendon of the ulnar flexor of the hand through the "block" with fixation to the base of the proximal phalanx of the first finger. A similar method, only using the tendon of the superficial flexor of the fourth finger, was proposed by C. Thompson and W. Blauth, using various variants of muscle-tendon transposition to restore the opposition of the first finger. E. Paneva-Holevich transplanted the lengthened tendon of the radial flexor of the hand, V. Sook, L. Schneider, J. Zweig, S. A. Goloborodko transplanted the extensor tendon of the V finger. K.Tsuge performed transposition of the long radial extensor of the hand.

With persistent damage to the ulnar and median nerves, not only the opposition of the first finger suffers, but also claw-like deformity of all fingers of the hand develops. E. Zancolli believes that with paralysis of the interosseous and vermiform muscles, the stabilization of the metacarpophalangeal joints is disturbed. In this regard, the extensors overextend the proximal phalanges of the II-V fingers and lose the ability to extend the middle and distal phalanges. On this basis, he developed an operation to stabilize the proximal phalanges of the II-V fingers. The essence of the Zancolli operation is capsuloplasty: the palmar capsule of the metacarpophalangeal joints is shortened by cutting out a flap and fixing it with shortening and bending of the proximal phalanx. However, the author himself, as well as other surgeons, noted a relapse of the deformity in 50% of cases.

To restore the opposition of the first finger, the following operation technique was proposed. From the incisions along the ulnar and radial edges of the forearm are isolated and cut off from the attachment points of the tendons of the radial and ulnar flexors of the hand. The distal end of the radial flexor tendon of the hand is sutured with an intra-trunk suture. The tendon of the ulnar flexor of the hand is lengthened by longitudinal splitting, the distal end is stitched in the same way. From the incision along the dorsal-radial surface, the first metacarpal bone is exposed. The tendons of the radial and ulnar flexors of the hand are passed through the subcutaneous tunnels to the first metacarpal bone. The tendon of the radial flexor of the hand is fixed to the upper third of the metacarpal bone, and the tendon of the ulnar flexor of the hand is fixed to the proximal phalanx of the first finger.

Some surgeons prefer an operation, the essence of which is that the tendon of the long flexor of the first finger is split in half. The ulnar part is left in place, and the radial part is moved to the dorsal-ulnar surface of the main phalanx of the first finger.

Reconstructive surgery for persistent damage to the ulnar nerve. As already mentioned, the main complaints in case of damage to the ulnar nerve, patients present with a claw-like deformation of the ulnar half of the hand, which prevents the palm from opening for grasping. Described different ways surgical treatment of the claw-like hand, however, preference is given to operations of a dynamic nature, restoring active flexion of the proximal phalanges of the fingers. Functionally most effective are two methods of musculo-tendon transposition of the superficial flexor from the middle phalanx to the proximal one.

In the first method, both legs of the superficial flexor tendon are cut off from the attachment point to the middle phalanx. The tendon is removed from the fibro-aponeurotic canal and split lengthwise into two halves. One leg is sutured and passed through the bony canal in the middle third of the proximal phalanx. The middle phalanx is unbent, and the proximal phalanx is removed from hyperextension by pulling the superficial flexor tendon to the flexion position to an angle of 20 °. Both legs of the superficial flexor are sutured.

In the second method, at the level IV-V of the metacarpophalangeal joints, the proximal part of the annular ligament is exposed and dissected transversely. The legs of the superficial flexor tendon are cut off and in the form of a loop they cover the proximal part of the annulus fibrosus. After tension and flexion of the proximal phalanx to an angle of 20 °, the distal end of the tendon is sutured to the same tendon.

The use of the described methods of dynamic operations ensures the restoration of the longitudinal arch of the hand, angina differentiated flexion of the proximal phalanges of the IV-V fingers, and the elimination of flexion contracture of the middle and distal phalanges.

Taking into account the deficit of adduction of the first finger for a stable power grip, the following technique of muscle-tendon transposition is advisable. From a longitudinal incision along the ulnar edge of the distal third of the forearm, the tendon of the ulnar flexor of the hand is isolated, mobilized and cut off from the attachment site. The latter is lengthened by longitudinal dissection and through the subcutaneous tunnel is carried out to the proximal phalanx of the 1st finger. From the incision along the neutral beam line at the level of the metacarpophalangeal joint, the ulnar flexor tendon of the hand is transosseously attached to the proximal phalanx in the position of adduction and pronation of the first finger. Thus, the function of the ulnar flexor of the hand provides stability and grip strength, and hyperextension of the proximal phalanx is corrected.

To eliminate excessive involuntary abduction of the V finger, it is possible to cut off the tendon of its extensor from the attachment site. The methods of operations are described, aimed not only at eliminating excessive abduction, but also at restoring the active adduction of the V finger to the IV. The operation consists in cutting off the extensor tendon of the V finger and fixing it to the tendon extensor aponeurosis of the V finger from the radial side.

The listed surgical interventions allow effective correction of all components of the hand deformity in case of persistent damage to the ulnar nerve.

Restoration of sensitivity in chronic damage to the nerves of the hand. A feature of chronic damage to the common and own palmar digital nerves is an increase in diastasis between the ends of the nerve trunk and the formation of a neuroma on the proximal segment of the nerve. In this regard, it is often necessary to perform plastic surgery of the nerves of the hand.

If the number of damaged nerves is significant, then it is advisable, if possible, to perform plastic surgery of the maximum number of nerves using one of the sural nerves as transplants. With a small number of damaged nerves, it is possible to dispense with the use of the donor area, thus not creating additional scars. In these cases, the intrinsic nerves of the hand, which innervate less functionally significant zones, can be used as transplants. You can also use the nerves on the back of the hand for this. Finally, with deep tissue defects, hand nerve defects can be replaced by a nerve trunk taken as part of a free complex of tissues transplanted into the defect.

The second option for restoring sensitivity in functionally important areas of the hand is transplantation of insular innervated flaps from the nondominant surface of the finger. Isolation is possible in two versions: on a wide skin base or on the neurovascular pedicle. One of the innervated flaps transplanted onto the palmar surface of the 1st finger is a graft from the dorsal-radial surface of the 2nd finger, which is supplied with blood from the 1st dorsal artery of the wrist, which includes the superficial branch of the radial nerve.

To restore a full-fledged sensitive skin of the hand, various donor sources of tissue complexes, including nerve branches, can be used. One of the most suitable grafts for the hand is the flaps fed from the pool of the 1st dorsal metatarsal artery. Reinnervation of tissues is carried out due to the deep branch of the peroneal nerve, which is sutured with the sensory nerve of the hand.

The described methods of surgical treatment provide a good functional effect for chronic damage to the nerves of the hand in children.

The median, ulnar and radial nerves take part in the innervation of the hand. The dorsum of the hand is innervated by the branches of the left and ulnar nerves, the palmar - by the median and ulnar nerves.

The ulnar nerve in the middle or lower third of the forearm is divided into dorsal and palmar branches. The dorsal branch passes between the ulna and the ulnar flexor tendon of the hand and, bending around the head of the ulna, passes to the dorsum of the hand, where it innervates the V, IV fingers and the side of the III finger adjacent to them.

The palmar branch is divided into two parts: superficial and deep. Superficial innervates the skin of the hypotenar m.palmares brevis. The terminal three branches of the superficial part of the nerve nn.digitales palmares proprii pass from under the palmar aponeurosis through the corresponding commissurial openings to the V finger and the ulnar surface of the IV finger and innervate their skin.

The deep palmar branch together with the ulnar artery passes under the palmar aponeurosis between the flexor et adductor digiti minimi, bends around the os hamatum hook, goes towards the radius between the deep flexor tendons of the fingers and the interosseous muscles.

The nerves extending from the deep branch innervate the thenar muscles, the third - fourth vermiform and interosseous muscles, the deep part of the short flexor of the first finger, the muscle leading to the first finger, the radial nerve in the epicondilus lateralis humeri area is divided into superficial and deep branches.

The superficial branch extends to the dorsum of the hand, where it innervates the skin of the radial edge of the hand, the first finger to the base of the nail plate, the skin of the second finger and the radial edge of the third finger to the middle phalanx.

The deep branch of the radial nerve is divided into its terminal branches between the superficial and deep muscles back surface forearms.

The muscle branches of the nerve innervate the extensor muscles of the hand and fingers. The median nerve runs between the superficial and deep flexors of the fingers, passes to the hand through the carpal canal, under the palmar aponeurosis along the anterior surface of the tendons of the superficial flexor of the fingers.

Own digital and palmar nerves innervate the skin of the palmar surface of the I-III fingers and the radial surface of the IV finger. In addition, the back cutaneous branches extend from the same nerves to the middle and nail phalanges of the II-IV fingers.

Muscular branches innervate the worm-like muscles, the superficial part of mflexor pollicis brevis, m.abductor pollicis brevis, m. opponens pollicis. Great importance has an accurate representation of the topography of the muscular branches of the median nerve, since when the latter are damaged, the important function of the muscles of the eminence of the first finger is disrupted.

The median nerve on the hand is projected at the proximal edge of the skin fold that separates the thenar region from the middle palmar part. The so-called "forbidden zone", where the first most important muscular branch of the median nerve is located, is defined between three conditional lines.

The first line is drawn from the radial edge of the distal skin fold of the wrist to the ulnar edge of the skin fold of the base of the V finger, the second line is drawn from the joint space formed by the first metacarpal and large polygonal bones to the third interdigital space. The third line is drawn from the first metacarpophalangeal joint horizontally to the ulnar side of the palm.

The distal base of the "forbidden zone" is formed by a straight line drawn from the intersection of the first and third lines to the second, so that the angles between this straight and the second and third lines are equal. During operations on the hand, you need to be especially careful in this area.

"Guide to purulent surgery",
V.I.Struchkov, V.K. Guestishchev,

The human hand, or the distal part of the upper limb, has a special meaning. With your hands and fine motor skills, movements of all fingers, people learn about the world and interact with it. The brush and fingers are the main tools in any work. A decrease in their functionality in many ways leads to a decrease in working capacity, to a limitation of human capabilities.

Joints and bones of the hand

The anatomy of the human hand is characterized by the presence of small bones articulating joints different types... There are three component parts of the hand: the wrist, the metacarpal part, the phalanges of the fingers. The wrist is commonly called the wrist joint, but from an anatomical point of view, it is the proximal part of the hand. It consists of 8 seeds arranged in two rows.

The first proximal row consists of three bones connected by fixed joints. A pea-shaped bone adjoins it from the lateral outer side, inherited from distant ancestors and serves to strengthen muscle strength(one of the sesamoid bones). The bony surface of the first row, facing the bones of the forearm, forms a single articular surface for connection with the radius.

Hand bones

The second row of bones is represented by four bones connected distally to the metacarpus. The carpal part is shaped like a small boat, where the palmar surface is its concave part. The space between the bones is filled with articular cartilage, connective tissue, nerves and blood vessels. Movement in the wrist itself and the movement of its bones relative to each other are almost impossible. But thanks to the presence of a joint between the wrist and the radius, a person can rotate the hand, bring it in and out.

The metacarpal part consists of five tubular bones. Their proximal part is connected to the wrist by fixed joints, and the distal part is connected to the proximal phalanges of the fingers by movable joints. The metacarpophalangeal joints are ball joints. They enable flexion and extension and rotational movements.

The thumb joint is saddle-shaped and provides only extension and flexion. Each finger is represented by three phalanges, which are connected by means of movable block-like joints. They flex and extend the fingers. All joints of the hand have strong joint capsules. Sometimes she capsule can unite 2-3 joints. There is a ligamentous apparatus to strengthen the osteoarticular frame.

Hand ligaments

Human hand joints are held and protected by a whole complex of ligaments. They have increased elasticity and at the same time strength due to very dense connective tissue fibers. Their function is to provide movement in the joints no more than the physiological norm, to protect them from injury. In cases of application of increased physical effort (falling, lifting weights), the ligaments of the hand can still be stretched, cases of rupture are very rare.

The ligamentous apparatus of the hand is represented by numerous ligaments: inter-articular, dorsal, palmar, collateral. The palmar part of the hand is covered with a flexor retinaculum. It forms a single channel in which the flexor tendons of the fingers pass. The palmar ligaments go in different directions, creating a thick fibrous layer, the dorsal ligaments are smaller.

The metacarpophalangeal and interphalangeal joints are reinforced with lateral collateral ligaments, and also have additional ones on the palmar surface. The flexor retainer ligament on the palm and the extensor retainer on the dorsum are involved in creating fibrous sheaths for these muscles. Thanks to them and the synovial spaces, the tendons are protected from external influences.

Hand muscles

Studying the anatomy of the human hand, one cannot but pay attention to the perfection of the structure of its muscular apparatus. All the smallest and most precise finger movements would be impossible without the coordinated work of all carpal muscles... All of them are located only in the palm, on the back side is the extensor tendon. By location, the muscles of the hand can be divided into three groups: the muscles of the thumb, the middle group and the small toe.

The middle group is represented by the interosseous muscles, which connect the bones of the metacarpal part, and worm-like muscles, which are attached to the phalanges. The interosseous muscles are brought together and spread apart, and their worm-like muscles are bent in the metacarpophalangeal joints. Muscle group the thumb is the so-called thenar, the elevation of the thumb. They bend and unbend it, take it away and bring it.

The hypotenar, or the eminence of the little finger (little finger), is on the other side of the palm. The muscle group of the thumb opposes it, retracts and leads, flexes and unbends. The movements of the hand in the wrist joint are provided by the muscles located on the forearm, due to the attachment of their tendons to the bones of the hand.

Blood supply and innervation of the hand

Bones and joints, muscles and ligaments of the hand are literally permeated with blood vessels. The blood supply is very well developed, which ensures high differentiation of movements and rapid tissue regeneration. From the forearm to the hand, two arteries, the ulnar and radial, approach, and, passing in special channels through the wrist joint, they find themselves between the muscles and bones of the hand. Here, an anastomosis (connection) is formed between them in the form of a deep and superficial arc.

Smaller arteries extend from the arches to the fingers, each finger is supplied with blood by four vessels. These arteries are also connected to each other, forming a network. Such a branched type of vessels helps with injuries, when the blood supply to the fingers is slightly affected when a branch is damaged.

The ulnar, radial and median nerves, passing through all the elements of the hand, end on the fingertips with a huge number of receptors. Their function is to provide tactile, temperature and pain sensitivity.

Well-coordinated and harmonious work of the hand is possible only with the preserved functionality of all of its component parts... A healthy hand is necessary for a full life of a person, to preserve his ability to work.

ENCYCLOPEDIA OF MEDICINE

ANATOMICAL ATLAS

Median and ulnar nerves

The median nerve innervates the muscles of the forearm, which provide flexion and pronation of the hand. The ulnar nerve runs behind elbow joint, where it can be felt by tapping on the inner condyle of the humerus, and innervates some of the small muscles of the hand.

Upper limb nerves (front view)

The median nerve of the upper limb exits the brachial plexus and travels down to the center of the elbow joint. It is the main nerve in the front of the forearm, where the muscles that flex and pronate the hand are located.

When moving to the area of ​​the hand, the median nerve stretches as part of the carpal canal (carpal tunnel). The terminal branches of the median nerve innervate some of the small muscles of the hand, as well as the skin of the thumb and several adjacent fingers.

ELBOW NERVE The ulnar nerve runs along the humerus towards the elbow and bends behind the inner epicondyle of the humerus where it can be easily felt under the skin. It gives branches to supply the elbow, two muscles of the forearm and the skin covering them, after which it passes to the hand. On the hand, the ulnar nerve is divided into deep and superficial branches.

MEDIAN NERVE INJURY The median nerve can be damaged by a fracture of the lower part of the humerus or compressed by swelling of the muscle tendons within the carpal tunnel (carpal tunnel syndrome). When the median nerve is injured, the patient cannot grasp the object with the thumb and other fingers, since the nerve is responsible for the mobility of the thenar muscles (the eminence of the thumb).

The ulnar nerve is especially vulnerable at the site of passage behind the medial epicondyle of the humerus. When the nerve is pressed against the underlying bone, a feeling of numbness appears in the hand. Severe trauma to the nerve can cause loss of sensation, paralysis, and wasting of the muscles it innervates.

T If the ulnar nerve is damaged, atrophy of the first dorsal interosseous muscle (on the dorsum of the thumb) may develop. In the image below, the area of ​​the atrophied muscle is circled.

This cross-sectional image of an arm (front view) shows the course of the ulnar, median, and musculocutaneous nerves.

This area can be easily felt under the skin.

Brachial bone

The bone of the upper arm.

Musculocutaneous nerve

This nerve innervates the muscles and skin of the hand; it is protected by muscles along its entire length, which protects it from damage.

Median nerve

Innervates the flexor muscles on the front surface of the forearm, as well as the muscles of the back of the hand and the first two fingers of the hand; provides sensitivity to the palmar surface of three and a half fingers from the thumb side.

(< ; Локтевой нерв

Innervates the area of ​​the elbow joint and some flexor muscles of the forearm; near the elbow lies superficially under the skin, and its irritation causes a tingling sensation in the hand. The nerve can be felt behind the inner epicondyle of the humerus.

Branch of the ulnar nerve

It innervates many of the own muscles of the hand, and also provides sensitivity to the palmar and dorsum of one and a half fingers from the little finger.

And the area marked with a marker on the hand corresponds to the area of ​​the skin innervated by the ulnar nerve. The radial and median nerves supply the rest of the hand.

Brachial plexus, plexus brachialis, formed by the anterior branches of the spinal nerves C5-C8 and, in part, Th1. It is located in the neck in the interstellar space. In this place, the brachial plexus is represented by the upper trunk, truncus superior, the middle trunk, truncus medius, and the lower trunk, truncus inferior, from which short branches extend to the muscles shoulder girdle... The trunks of the brachial plexus with short branches extending from them make up the supraclavicular part, pars supraclaviculars, of the brachial plexus.

In the supraclavicular region, the trunks of the brachial plexus begin to divide, exchange bundles of fibers with each other, and ultimately form three bundles. These bundles, together with the subclavian artery and vein, penetrate through the opening bounded by the I rib, the clavicle and the upper edge of the scapula into the axillary cavity. The bundles surround the axillary artery on three sides and, according to their position, are called: medial bundle, fasciculus medialis, lateral bundle, fasciculus lateralis, and posterior bundle, fasciculus posterior. Parts of the bundles located below the clavicle make up the subclavian part, pars infraclavicularis, brachial plexus. They are 1.5-5 cm long and then split into long branches (nerves) that innervate the free upper limb.

The branches of the supraclavicular part of the brachial plexus follow to the muscles of the shoulder girdle and, therefore, contain predominantly motor fibers... In addition, afferent fibers from the proprioceptors of these muscles and sympathetic fibers to the vessels pass through them.

1. Dorsal nerve of the scapula n. dorsalis scapulae, starts from the anterior branch of the V cervical nerve (C5), goes out between the beginning of the anterior and middle scalene muscles, lies on the anterior surface of the muscle that lifts the scapula, and then goes back along with the descending branch of the transverse artery of the neck. Innervates mm. levator scapulae, rhomboideus major et minor.

2. Long pectoral nerve, n. thoracicus longus, starts from the front branches V-VII cervical nerves(C5-C7), descends behind the brachial plexus to the lateral surface chest... Innervates m. serratus anterior.

3. Subclavian nerve, n. subclavius, starts from the front branch of n. spinalis C5, a thin nerve, passes first along the anterior scalene muscle, and then in front of a. subclavia. Innervates m. subclavius.

4. Suprascapular nerve, n. suprascapular, starts from the upper trunk, contains fibers from the anterior nn branches. spinales C5-C7, goes to the supraclavicular region, and then through the incisura scapulae enters the supraspinatus fossa. Innervates m. supraspinatus, m. infraspinatus and capsule shoulder joint.

5. Lateral and medial pectoral nerves , nn. pectorales lateralis et medialis, start from the lateral and medial bundles of the brachial plexus, contain fibers from the anterior branches of the nn. spinales C5-Th1 pass behind the clavicle, pierce the clavicular-pectoral fascia and branch. The medial nerve innervates m. pectoralis major, lateral - m. pectoralis minor.

6. Subscapularis nerve, n. subscapulars, starts from the posterior bundle of the brachial plexus, contains fibers from the anterior branches of the nn. spinales C5-C8, bends around the posterior scalene muscle and in the region of the lateral angle of the scapula penetrates into the subscapular fossa. Innervates tm. subscapulars, teres major.

7. Thoracic nerve, n. thoracodorsal, starts from the posterior bundle, contains fibers from the anterior nn branches. spinales С7-С8, descends along the lateral edge of the scapula. Innervates m. latissimus dorsi et m. serratus anterior.

Branches of the subclavian part of the brachial plexus. From the medial bundle originate the medial cutaneous nerve of the shoulder, the medial cutaneous nerve of the forearm, the ulnar nerve and the medial root of the median nerve. From the lateral bundle originate the musculocutaneous nerve and the lateral root of the median nerve. The axillary and radial nerves begin from the posterior bundle.

1. Medial cutaneous nerve of the shoulder n. cutaneus brachii medialis, contains sensitive and sympathetic nerve fibers from the anterior branches of the nn. spinales C8-Th1 ,. Initially, it accompanies the brachial artery with one trunk, and then divides into 2-3 branches, which pierce its own fascia of the shoulder and innervate the skin and subcutaneous fatty tissue of the medial surface of the shoulder. At the base axillary fossa the medial cutaneous nerve of the shoulder gives off 1-2 branches, which are connected to the lateral cutaneous branches of the II-III intercostal nerves, resulting in the formation of the intercostal-brachial nerves, nn. intercostobrachiales. They innervate the skin of the armpit.

2. Medial cutaneous nerve of the forearm, n. cutaneus antebrachii medialis, contains sensitive and sympathetic fibers from the anterior branches of the nn. spinales C8-Th1. Initially, it accompanies the brachial artery, in the middle of the shoulder along with v. basilica pierces its own fascia of the shoulder and divides into the anterior and ulnar branches, ramus anterior et ramus ulnaris, which descend to the forearm. It innervates the skin and subcutaneous fatty tissue of the anterior and medial surface of the forearm.

3. Ulnar nerve, n. ulnaris, mixed, contains fibers from the anterior branches of the nn. spinales С7-Тh1 Up to the middle of the shoulder passes next to the brachial artery, then deviates medially and posteriorly, pierces the medial intermuscular septum and lies in the sulcus cubitalis posterior medialis. From this groove, it enters canalis ulnaris, then passes to the forearm into sulcus ulnaris, where it accompanies the artery and veins of the same name. It has no branches on the shoulder. On the forearm, the ulnar nerve gives off muscle branches, rr. musculares that innervate m. flexor carpi ulnaris and medial part of m. flexor digitorum profundus. In addition, thin branches extend from it to the capsule of the elbow joint.

In the lower third of the forearm, the dorsal branch, r, begins from the ulnar nerve. dorsalis n. ulnaris, which runs to the back of the forearm between the flexor ulna of the hand and the ulna. By piercing its own fascia of the forearm at the level of the head of the ulna, this branch is divided into 5 dorsal digital nerves, nn. digitales dorsales, which innervate the skin of the V, IV and ulnar side of the III fingers. It should be noted that on the third and fourth fingers, the innervation of the skin by the ulnar nerve is carried out only up to the level of the middle phalanges.

On the palmar surface of the hand, the ulnar nerve gives off the palmar branch, r. palmaris n. ulnaris, which is located in front of the retinaculum flexorum. The main trunk of the ulnar nerve passes into the canalis carpi ulnaris and is divided into superficial and deep branches. Surface branch, r. superficialis, innervates m. palmaris brevis, gives off its own palmar digital nerve, n. digitalis palmaris proprius, to the skin of the medial surface of the V finger and the common palmar digital nerve, n. digitalis palmaris communis, which is divided into two own palmar digital nerves that innervate the skin of the lateral surface of the V finger and the medial surface of the IV finger.

The deep branch of the ulnar nerve penetrates through the canalis hamomuscularis and innervates all muscles of the hypotenar (m. Flexor digiti minimi brevis, m. Abductor digiti minimi, m. Opponeus digiti minimi), all mm. interossei, mm. lumbricales III and IV, m. adductorpollicis, deep head m. flexor pollicis brevis. In addition, the deep branch is involved in the innervation of the hand joints.

4. Median nerve, n. medianus, mixed, is formed from two roots (from the medial and lateral bundles of the brachial plexus), which connect on the anterior surface of the axillary or brachial arteries, contains fibers from the anterior branches of the nn. spinales C6-Th1 ,. In the area of ​​the shoulder, the nerve passes next to the brachial artery in the sulcus bicipitalis medialis and does not give up branches. In the cubital fossa, it passes under the aponeurosis m. biceps brachii, where it gives off branches to the elbow joint. Then it penetrates m. pronator teres and lies in the sulcus medianus. On the forearm, the median nerve gives off numerous muscle branches, with which it innervates the muscles of the anterior group of the forearm (flexors), with the exception of m. flexor carpi ulnaris and medial part of m. flexor digitorum profundus (these muscles are innervated by n.ulnaris), as well as m. brachioradialis (innervates n. radialis).

The largest branch is n. medianus on the forearm is the anterior interosseous nerve, n. interosseus anterior, located on the anterior surface of the anterior interosseous membrane. He gives branches to deep muscles the front surface of the forearm and to the wrist joint.

In the lower third of the forearm from n. medianus begins the palmar branch of the median nerve, n. palmaris n. mediani, which innervates the skin at the wrist joint, the middle of the palm, and the eminence of the thumb.

On the palmar surface of the hand, the median nerve passes through the canalis carpi together with the flexor tendons of the fingers and under the palmar aponeurosis is divided into terminal branches - muscle and skin. Muscular branches innervate the muscles of the thumb (m. Abductor pollicis brevis, m. Opponens pollicis, superficial head m. Flexor pollicis brevis), as well as mm. lumbricales I, II. The terminal cutaneous branches are the three common palmar digital nerves, nn. digitales palmares communes. These nerves are located under the superficial palmar (arterial) arch in the corresponding interdigital spaces. N. digitalis palmaris communis I is divided into 3 own palmar digital nerves, nn. digitales palmares proprii, two of which go to the thumb, and the third to the lateral surface of the index finger. Nn. digitales palmares communes II, III are divided each into two own palmar digital nerves, going to the skin of the surfaces of the II, III and IV fingers facing each other, as well as to the skin of the dorsum of the distal and middle phalanges of the II and III fingers.

5. Musculocutaneous nerve, n. musculocutaneus, mixed, starts from the lateral bundle of the brachial plexus, contains fibers from the anterior branches of the nn. spinales C5-C8. After discharge, the nerve is directed laterally and down, penetrates m. coracobrachialis, runs between the posterior surface of m. biceps brachii and the front surface of m. brachialis and lies in the sulcus bicipitalis lateralis. In the lower part of this groove, branches extend from it to the capsule of the elbow joint. In the shoulder area n. musculocutaneus innervates all the muscles of the anterior groin (flexors), giving them muscle branches, rr. musculares. In the lower third of the shoulder n. musculocutaneus pierces its own fascia of the shoulder and descends on the forearm in the form of a lateral cutaneous nerve of the forearm, n. cutaneus antebrachii lateralis. This nerve innervates the skin and subcutaneous fatty tissue of the anterolateral surface of the forearm.

6. Axillary nerve n. axillaris, mixed, starts from the posterior bundle of the brachial plexus, contains fibers from the anterior branches of the nn. spinales C5-C8. After discharge, the nerve passes along the anterior surface of m. subscapulars and together with a. circumflexa humeri posterior penetrates through the foramen quadrilaterum, bending around the surgical neck of the humerus. Then it splits into branches and innervates m. deltoideus, m. teres minor and shoulder capsule. One of the branches and. axillaris - upper lateral cutaneous nerve of the shoulder, n. cutaneus brachii lateralis superior, emerges from under the posterior edge of m. deltoideus and innervates the skin of the posterolateral region of the shoulder in the upper section.

7. Radial nerve, n. radialis, mixed, starts from the posterior bundle of the brachial plexus, contains fibers from the anterior branches of the nn. spinales C5-C8. Within the upper third of the shoulder, the nerve is located in the sulcus bicipitalis medialis behind a. brachialis, and then together with the deep artery of the shoulder in the canalis humeromuscularis. Through the lower opening of the canalis humeromuscularis, the radial nerve penetrates into the sulcus cubitalis anterior lateralis, in the depths of which it is divided into superficial and deep branches.

On the shoulder n. radialis innervates the muscles of the posterior groin (extensors) and the capsule of the shoulder joint. Even in the axillary cavity, the posterior cutaneous nerve of the shoulder, n. cutaneus brachii posterior, which runs through the long head of m. triceps brachii, the own fascia of the shoulder and innervates the skin and subcutaneous fatty tissue of the postero-lateral surface of the shoulder.

The canalis humeromuscularis from n. radialis, the posterior cutaneous nerve of the forearm departs, n. cutaneus antebrachii posterior, which pierces the proprietary fascia of the shoulder above the lateral epicondyle and innervates the skin of the posterior surface of the shoulder, elbow and forearm.

Superficial branch of the radial nerve, n. superficialis n. radialis, on the forearm lies in the radial groove outward from the radial artery. In the lower third of the forearm, it passes to the dorsum and is located between the brachioradialis muscle and the radius. 4-5 cm above the styloid process of the radius, this branch pierces its own fascia of the forearm, gives off branches to the base of the thumb and is divided into 5 dorsal digital nerves, nn. digitales dorsales. Two of these nerves innervate the skin of the thumb, the other three branch out in the skin of the II and the lateral surface of the III fingers. Moreover, the last three nerves reach only the level of the middle phalanges, the middle and distal phalanges of these fingers innervate the median nerve.

Deep branch of the radial nerve, n. profundus n. radialis, from the anterior lateral ulnar groove penetrates into the canalis supinatorius, bends around the neck of the radius and extends to the posterior surface of the forearm. It innervates all the muscles of the back of the forearm (extensors) and the brachioradialis muscle. The final branch n. profundus is the posterior interosseous nerve, n. interosseus posterior, which accompanies the posterior interosseous artery and gives branches to the deep muscles of the posterior group of the forearm.