Forearm muscles front view deep layer. Forearm muscles

If you bend your hand palm up at a right angle at the elbow so that the hand experiences strong resistance, you can see that the muscles of the forearm consist of two arrays (see Fig. 38). One array is internal: its muscles mainly start from the internal epicondyle of the shoulder and stretch to the palm. Another array is external: its muscles start mainly from the external epicondyle and stretch to the back of the hand. The border between these arrays from the rear is the ulna - it can be felt all the way from top to bottom, and from the palmar side - the ulnar (muscular) fossa, into the depths of which the tendon of the biceps muscle of the shoulder goes.

The muscles of the forearm mainly move the hand and fingers. Their muscular parts are located on the forearm, and downwards they pass into the tendons that stretch to the hand. From this, the forearm is expanded at the top, and narrowed at the bottom. The tendons of the muscles that move the fingers are attached to the phalanges, and the tendons of the muscles that move the hand, with the exception of two, are attached to the metacarpal bones. The muscles of the internal array are mainly flexors, the muscles of the external array are extensors.

1 The flexor group (Fig. 38, 39) consists of superficial and deep muscles. The superficial muscles include the round pronator, radial flexor tassels, long palmar muscle, ulnar flexor of the hand.

Round pronator. It stretches obliquely from the inner epicondyle to the radius, bends around it and attaches to it in such a way that, contracting, it turns the radius along with the hand with the palm down - it penetrates and bends the forearm.

Radial flexor of the hand (wrist). Lies next to the pronator. Its tendon goes obliquely and is attached to the base of the second metacarpal bone.

Action. Bends the hand, tilting it towards the beam (i.e., towards thumb).

Long palmar muscle. It lies next to the previous one, the tendon goes to the middle of the palm and is woven into the palmar aponeurosis.

Action. Bends the brush straight.

Elbow flexor of the hand (wrist). Flat, very wide, with one edge adjacent to the long palmar muscle, the other - to the ulna

Rice. 39. Muscles of the forearm (right). A - palmar surface:

1- biceps shoulder, 2 - shoulder muscle, 3 - tendon of the biceps muscle, 4 - Pirogov fascia, 5 - long radial extensor of the hand, 6 - shoulder muscle. 7 - short radial extensor of the hand. 8 - radial flexor of the hand. 9 - long palmar muscle. 0 - short extensor and long abductor of the thumb, // - muscle elevation of the thumb! finger, 12 - palmar aponeurosis, 13 - tendon of the long flexor of the thumb. 14 - tendons of the deep flexor of the fingers, / 5 tendons of the superficial flexor of the fingers, 16- muscle elevation of the little finger, 17 - pisiform bone, 18 - transverse carpal ligament.. 19 - superficial finger flexor. 20 - ulnar flexor of the hand, 21- round pronator, 22 - internal condyle of the shoulder. 23 - shoulder muscle, 24 - triceps;

B - outside surface:

1 - triceps muscle of the shoulder. 2 - olecranon. 3 - external condyle of the shoulder, 4 - elbow! muscle. 5 - ulnar extensor brushes. 5 - common extensor of the fingers, 7 - head of the ulna. 8 - attachment of the tendons of the radial extensor of the hand, 9 - attachment of the tendon of the ulnar extensor of the hand, 10 - dorsal interosseous muscles, II- metacarpal heads 12- adipose tissue. 13 - tendon of the long extensor of the thumb. 14 - first dorsal interosseous muscle 15 - short extensor of the thumb, 16- long abductor muscle of the thumb. 17 - anatomical snuffbox. 18 - dorsal transverse ligament of the wrist. 19 - short radial extensor of the hand, 20- long radial extensor of the hand. 21 - shoulder muscle, 22 -shoulder muscle 23 - biceps muscle

bone from which it partly originates. Below it forms a short tendon, which is attached to the pisiform bone.

Action. Flexes the hand towards the ulna.

Bend the supinated hand without bending the fingers (Fig. 39); at the wrist, three tendons protruding under the skin are visible. If we consider them from the thumb to the little finger, then the tendon of the radial flexor lies first, then the long palmar muscle, and finally the tendon of the ulnar flexor. If, while maintaining the same position of the hand, bend the fingers (except the thumb) so that the pads of the fingers lie against the bottom of the palm, you can see that the tendons of the flexors of the hand remain motionless, and move behind them in depth muscle mass, - these are contracted deep muscles - finger flexors; There are two of them: superficial and deep. Each is divided into four tendons, going to all fingers except the thumb; the tendons of the superficial flexor are attached to the II phalanges - in this case, this muscle is mainly reduced. With even greater flexion of the fingers with the bending of the nail phalanges inward, an additional contraction of the muscles of the forearm is visible - this is a contraction of the deep flexor of the fingers; its tendons are attached to the nail phalanges. Flexion of fingers is made completely.

2. Extensor group. The brachioradialis muscle (Fig. 38, 39) (not being an extensor, makes up a plastic whole with the extensors, therefore it is described together with them) starts from the outer edge humerus above the epicondyle, stretches down and attaches to the radius above its styloid process.

Action. Flexes the arm at the elbow and sets the forearm in a position intermediate between pronation and supination. Very embossed with intense flexion at the elbow (see Fig. 38).

The remaining muscles of this group, starting from the external epicondyle, bend around it so that on the arm straightened at the elbow they form a deepening-fossa of beauty, in which you can feel both the condyle and the head of the beam.

Long radial extensor of the hand. It has a short muscular belly (when stressed, it takes an ovoid shape) and a long tendon.

Short radial extensor. It has a spindle-shaped abdomen and a shorter tendon. The tendons of both muscles descend along the radius, pass below, as in a tunnel, between the bone and the muscles of the thumb that are thrown over them and are attached on the back of the hand to the bases of the II and III metacarpal bones (Fig. 39).

Action. Unbend the brush towards the beam (thumb).

Common extensor of the fingers. Lies next to the previous one. It is divided into four tendons, which pass to the back of the hand (where they are very prominent when extended) and are attached to the nail phalanges of the II-V fingers (Fig. 39).

Action. Extends these fingers.

The index finger (II) and the little finger (V) can be freely unbent separately from the others (which is easy to see on own hand). This is due to the presence of separate additional extensors of these fingers, which do not have a noticeable relief.

Elbow extensor of the hand. It stretches obliquely from the epicondyle between the previous and the ulnar muscle to the ulna and partly fuses with it. Its tendon is thrown from the head of the ulna to the hand, it is relief in this gap and is attached to the base of the fifth metacarpal bone (Fig. 39).

Action. Unbends the brush towards the elbow (little finger).

Elbow muscle. Triangular in shape, short, lies between the previous muscle and the ulna. It starts from the outer condyle of the shoulder, is attached to the upper part of the ulna.

Action. Extends the arm at the elbow.

Small supinator. It lies deep in the upper part of the forearm, has no plastic significance.

Action. Supinates the forearm and hand.

Muscles of the thumb. They lie apart (Fig. 39).

Abductor pollicis longus and extensor pollicis brevis. They begin in the depths of the forearm and appear on the surface from under the edge of the common extensor of the fingers. The first muscle lies above the second. They are bridged over the tendons of the radial extensor of the hand. Then they pass into the tendons, which, in the form of a common strand, are transferred from the radius, bypassing the wrist, to the base of the first metacarpal bone. The long abductor muscle is attached here, and the short extensor muscle reaches the 1st phalanx of the thumb, where it is attached.

Action. The names of the muscles clearly indicate their action. In addition, both muscles abduct the hand outward, while their muscular parts are embossed on the muscular arm, and above them, with a strong extension of the hand, a longitudinal depression is formed, since in this case the muscular part of the radial extensors is pulled upward.

Long extensor of the thumb (Fig. 39). It lies in depth, its tendon appears from under the edge of the common extensor of the fingers at the level of the wrist and passes to the nail phalanx of the thumb, where it is attached.

Action. Unbends the thumb, while the tendon is very prominent.

When the thumb is abducted and extended, the tendon of the long extensor and the common strand of the tendons of its other two muscles form a triangular fossa - an anatomical snuffbox, in the depth of which you can feel the styloid process of the radius, a large polygonal bone of the wrist and the base of the first metacarpal bone (see Fig. 39) .

Long flexor of the thumb (Fig. 39). Lies on palmar surface radius covered with other muscles; its tendon runs in depth to the 1st phalanx of the thumb. The muscle lies close to the skin on the palmar surface of the lower end of the radius, and here its contraction when the thumb is flexed is noticeable in the form of a small depression.

All the above muscle actions reproduce and check on the model and on your own hands.

Dorsal and palmar ligaments of the wrist. Strong transverse ligaments attached to the bones are bridged over the tendons of the muscles at the points of their transition from the forearm to the hand on the back and palmar sides and hold the tendons near the bones over which the tendons move. Above them, during flexion and extension, transverse skin folds are formed (Fig. 39).

Some muscles of the forearm move the brush other- fingers. The muscles that move the hand almost all bypass the wrist and are attached to the metacarpus, which makes it possible, with extensive movements of the hand, to bring the metacarpus to the forearm as close as possible (see Fig. 4, tables I, III) from one side of the joint, pushing the wrist to the opposite side, which is the reason for the change in the length of the hand (see the skeleton and movements of the hand, pp. 48, 49).

In addition, the muscles that move the hand are attached to it with different parties: radial extensors - to the rear of the II and III metacarpal bones, ulnar extensor - to the rear of the V metacarpal bone, radial flexor - to the palmar side of the II metacarpal bone, long palmar - to the middle of the palm, ulnar flexor - to the pisiform bone. Thanks to this, the muscles can move the hand in different directions and, in addition, while contracting, fix it in any position, and both fixation and these movements give complete freedom to the movements of the fingers. If you relax the muscles of the hand and chat in the air with your forearm, the hand will dangle like a rag (we make this movement when we dry wet hands), but the flabbiness of the hand instantly disappears, even if you continue to move the forearm, if you simultaneously strain all the muscles of the hand and thereby fix it .

With a strong physical activity(for example, when lifting weights), in addition to the work of the fingers, fixation of the hand is required. Therefore, in such cases, the muscles of the forearm are completely tense, which is reflected in their relief.

In work that does not require strong physical exertion, the hand and fingers move with simultaneous tension. various muscles moving the hand and fingers. If these movements are complex, then they are not mastered immediately, but through exercises (as mentioned above).

Analyze several working movements of the hand on the model and on yourself and be aware of which muscles move the hand and which move the fingers. Consider the change in the shape of the forearm during pronation and supination.

Questions. The two main mouse forearm arrays and their borders. Flexor group: pronator round, flexors of the hand, flexors of the fingers. Extensor group, brachioradialis and ulnar muscles. Muscles of the thumb Anatomical snuffbox. The action of the muscles that move the hand. The action of the muscles that move the fingers. their simultaneous action. Brush fixation.

The muscles of the forearm are divided into three groups: anterior, posterior and lateral (radial).
front group Surface layer:
1. Round pronator muscle, m. pronator teres.
2. Radial flexor of the wrist, m. flexor carpii radialis.
3. Long palmar muscle, m. palmaris longus.
4. Elbow flexor of the wrist, m. flexor carpii ulnaris.
5. Superficial flexor muscle of the fingers, m. flexor digitorum superficialis. Deep Layer:
1. Deep muscle-flexor of the fingers, m. flexor digitorum profundus.
2. Long flexor muscle of the thumb, m. flexorpolicis longus.
3. Square muscle-pronator, m. pronator guadratus.
back group Surface layer:
1. Elbow extensor of the wrist, m. extensor carpii ulnaris.
2. The extensor muscle of the fingers, m. extensor digitorum.
3. The extensor muscle of the little finger, m. extensor digiti minimi. Deep Layer:
1. Muscle-arch support, m. supinator.
2. Long abductor muscle of the thumb, m. abductor pollicis longus.
3. Short extensor muscle of the thumb, m. extensor pollicis brevis.
4. Long extensor muscle of the thumb, m. extensor pollicis longus.
5. The extensor muscle of the index finger, m. extensor indicator.
Lateral (beam) group: 1. Shoulder-radial muscle, m. brachioradialis.
2. Long radial muscle-extensor of the wrist, m. extensor carpi radialis longus.
3. Short radial muscle-extensor of the wrist, m. extensor carpi radialis brevis.

Front group (surface layer)

1. teres pronator muscle, m. pronator teres - together with m. brachioradialis limits the cubital fossa. It has two heads: caput humerale - originates from the epicondylus medialis os humeri and from the muscular septum of the shoulder; caput ulnare - originates from the ulnar tuberosity. It is attached by a common abdomen to the lateral edge of the middle part of the radius.
Function: penetrates the forearm and takes part in its flexion. Blood supply: a. musculares aa. brachialis, ulnaris, radialis. Innervation: n. medianus (C VI-C VII).
2. Radius flexor muscle wrists, m. flexor carpi radialis - originates from epicondylus medialis, fascia antebrachii, septa intermuscularis and is attached to the base of ossa metacarpi (II).
Function: flexes and pronates the wrist.
Blood supply: rr. muscularis a. radialis.
Innervation: n. medianus (C VI-C VIII).
3. long palmar muscle, nn. palmaris longus - originates from epicondylus medialis and fascia antebrachii, passes into a thin fibrous plate, aponeurosis palmaiis.
Function: stretches the palmar aponeurosis and is involved in wrist flexion.
Blood supply: rr. muscularis a. radialis.
Innervation: n. medianus (C VII, C VIII).
4. Elbow flexor of the wrist, m. flexor carpii ulnaris - originates from two heads: caput humerale - from epicondylus medialis os humeri and antebrachii fasciae; caput ulnare - from olecranon and upper bridge fascies dorsalis ulnae Attached to the pisiform bone, from which the tendon continues to os hamaturn in the form of lig. pisohamatum and to o.s metacarpale (V).
Function: flexes the wrist and takes part in its adduction.
Blood supply: aa. collateralis, a. brachialis et a. ulnaris.
Innervation: n. ulnaris (C VIII-Ti I).
5. Superficial finger flexor muscle, m. flexor digitorum superficialis - originates from two heads: the shoulder-ulnar head, caput humeroulnare - from the medial epicondyle of the shoulder and the coronoid process of the ulna; radial head, caput radiale, - from the proximal part of the radius. In the middle third of the forearm, the heads are connected into four long tendons, which pass to the wrist, where they lie in the canalis carpi and are attached to the base of the middle phalanges from the II to IV fingers. At the level of the phalanges, the tendon divides into two legs, which are attached to the edges of the base of the middle phalanges.
Function: bends the middle phalanges of the II-V fingers. Being a multi-angled muscle, it flexes in all joints of the hand, except for the distal interphalangeal joints, flexes the fingers and leads them to the middle finger.
Blood supply: rr. musculares aa. radiales et ulnaris.
Innervation: n. medianus (C VII-C VIII, Th I).

Front group (deep layer)

1. Deep finger flexor muscle, m. flexor digitorum profundus, originates from the proximal half of the ulna and the interosseous membrane. Four long tendons of the muscle pass through the canalis carpalis and are attached to the distal phalanx from the II to V fingers.
Function: bends the middle phalanges of the II-V fingers. Being a multi-angled muscle, it flexes in all joints of the hand, including flexion of the distal phalanges. The tendons of the deep flexor muscle diverge into the hands towards the fingers, as a result of which this muscle not only flexes the fingers, but also adducts them.
Blood supply: rr. musculares a. ulnaris.
Innervation: n. ulnaris n. medianus (C VI-C VIII, Th I).
2. Long flexor muscle of the thumb, m. flexorpolicis longus, - originates from the anterior surface of the radius, from the medial epicondyle of the shoulder. Attached to the base of the distal phalanx of the thumb.
Function: flexes the nail phalanx of the thumb and all joints in which it passes.
Blood supply: rr. musculares aa. radialis, ulnaris et a. interossea anterior.
Innervation: n. medianus (C VI-C VIII).
3. Quadratus pronator muscle, m. pronator guadratus - a thin quadrangular plate that is located at the distal ends of the bones of the forearm. It originates from the distal part of the volar surface of the ulna and is attached to the volar surface of the radius.
Function: penetrates the forearms.
Blood supply: a. interossea anterior.
Innervation: n. medianus (C VI-C VIII).

Lateral group

1. brachioradialis muscle, m. brachioradialis - originates from the lower third of the lateral edge of os humerus and the intermuscular lateral membrane of the shoulder, goes down and attaches to the radius above the styloid process.
Function: flexes the forearm and takes part in the pronation and supination of the radius.
Blood supply: aa. collateralis, a. profnda brachii et a. recurrens radialis.
Innervation: n. radialis (C V-C VII).
2. Extensor carpi radialis longus, m. extensor carpii radialis longus, - located superficially under the skin, has a spindle shape. Grows below m. brachioradialis from the septum intermuscular laterale of the shoulder, epicondylus laterale os humeri. The long tendon of the muscle passes to the fascies dorsalis radii, passes under the extensor holder and is attached to the back side of the base of the os metacarpal (II).
Function: this muscle is a strong extensor of the hand, takes part in its abduction and extends the wrist.
Blood supply: aa. collaterales, a. profundae brachii et a. recurrens radialis.
Innervation: n. radialis (C V-C VII).
3. Short radial muscle-extensor of the wrist, m. extensor carpi radialis brevis - originates from the lateral epicondyle of the humerus, forearm fascia, lig. collaterale and anulare radii, attached to the dorsal side of the substrate os metacarpale (III).
Function: unbends the brush and at the same time withdraws it.
Blood supply: aa. collaterales a. profundae brachii et a. recurrens radialis.
Innervation: n. radialis (C VI-C VII).

Rear group (surface layer)

1. Elbow extensor of the wrist, m. extensor carpii ulnaris originates from the lateral epicondyle of the humerus, the fascia of the forearm and the capsule of the elbow joint, is attached to the base of the os metacarpale (V).
Function: unbends and adducts the hand.
Blood supply: a. interossea posterior.
Innervation: n. radialis (C VII-C VIII).
2. Finger extensor muscle, m. extensor digitorum - originates from the lateral epicondyle of the humerus, fascia of the forearm, lateral and annular ligament of the elbow joint, passes under the retinaculum extensorum, attaches to the middle and distal phalanges. The individual extensor tendons of the fingers are interconnected by three oblique intertendinous bridges, connexus intertendineus.
Function: unbends the phalanges in the interphalangeal joints, takes part in the extension of the hand.
Blood supply: a. interossea posterior.
Innervation: n. radialis (CVI-CVIII).
3. Little finger extensor muscle, m. extensor digiti minimi - originates from the lateral epicondyle of the humerus c. fascia antebrachii and is attached to the middle and distal phalanx of the fifth finger, merging with the corresponding tendon of the common extensor of the fingers.
Function: unbends the little finger and to some extent unbends and adducts the hand.
Blood supply: a. interossea posterior.
Innervation: n. radialis (CVI-CVIII).

Back group (deep layer)

1. Arch support muscle, m. supinator - originates from the lateral epicondyle of the humerus, from lig. anulare radii, crista m. supinator ulnae and the capsule of the elbow joint, is attached to the lateral edge of the radius opposite the place of attachment of m.pronator teres.
Function: rotates the forearm from the outside.
Blood supply: aa. recurrens radialis, recurrens interossea., a. radialis.
Innervation: n. radialis (C V-C VIII).
Abductor pollicis longus muscle, m. abductor pollicis longus - originates from rear surface the upper third of the ulna and radius and from the membrana interossea, bends around the radius with its tendons, passes under the retinaculum extensorum and is attached to the base of the os metacarpale (I).
Function: abducts the thumb, takes part in the abduction of the hand.
Blood supply:
Innervation: n. radialis (C VI-C VIII).
Short extensor muscle of the thumb, m. extensor pollicis brevis - originates from the dorsum of the radius and the interosseous membrane, passes under the retinaculum extensorum, attaches to the base of the first phalanx of the thumb.
Function: extends the first finger at the metacarpophalangeal joints.
Blood supply: a. interossea posterior, a. radialis.
Innervation: n. radialis (C VI-C VIII).
Long extensor muscle of the thumb, m. extensor pollicis longus - originates from the posterior surface of the radius and the interosseous membrane, the tendon passes under the retinaculum extensorum, attaches to the base of the distal phalanx of the thumb.
Function: unbends the distal phalanx and abducts the thumb.
Blood supply: a. interossea posterior, a. radialis.
Innervation: n. radialis (C VI-C VIII).
The extensor muscle of the index finger, m. extensor indicis - originates from the lower third of the ulna, the interosseous membrane, together with the tendon of the common extensor of the fingers, passes under the extensor holder and is attached to the back surface of the proximal phalanx of the index finger, woven into the tendon extensions of the extensor of the fingers.
Function: unbends the index finger and contributes to the extension of the entire brush.
Innervation: n. radialis (C VI-C VIII).
Blood supply: a. interossea posterior.

Biceps. Its two heads start from the scapula and come out from under the pectoralis major muscle. This muscle descends to the forearm, where its tendon goes into the cubital fossa and attaches to the tuberosity of the radius. The muscle flexes and supinates the forearm.

beak-shoulder muscle located next to short head biceps muscle. It starts from the coracoid process of the scapula, emerges from the armpit and attaches to the humerus. Muscle leads And flexes the humerus. The plastic significance of the muscle is that when the arm is raised and retracted, it, together with the short head of the biceps muscle of the shoulder, forms a roller protruding under the skin along its course.

Rice. 47. Belt muscles upper limb and shoulder:

A - muscles of the girdle of the upper limb and shoulder (front view), B - humerus (a - front view, b - rear view), C - muscles of the girdle of the upper limb and shoulder (back view), D - scapula (a - front view , b – rear view):

1 – deltoid, 2 - supraspinatus muscle, 3 - infraspinatus muscle, 4 - small round muscle, 5 - large round muscle, 6 - biceps of the shoulders, 7 - aponeurosis of the biceps of the shoulder, 8 - beak-shoulder muscle, 9 - shoulder muscle, 10 - triceps muscle , eleven - ulnar muscle, 12 – round pronator.

shoulder muscle flexes the arm at the elbow joint. It lies under the biceps brachii. It starts from the anterior surface of the humerus below the level of attachment of the deltoid muscle and, descending on the forearm, is attached to the tuberosity of the ulna. The muscle protrudes from the inner and outer sides of the biceps brachii, especially in its lower section. Along the course of these two muscles between them is outdoor And internal double-headed furrows.

Forearm extensors.

The entire posterior surface of the humerus is triceps muscle of the shoulder. Her long head starts at the shoulder blade (subarticular tubercle), and the internal and external - from the humerus. The muscle attaches to the olecranon of the ulna. She extends the arm at the elbow joint and brings the shoulder to the body.

Muscles of the forearm.

There are two main muscle groups on the forearm, of which one begins in the region of the internal epicondyle of the humerus, passes to the anterior (palmar) surface of the forearm and makes up the group wrist flexors And fingers. Another group begins in the region of the external epicondyle of the humerus, passes along the posterior (dorsal) surface of the forearm and makes up the group extensor hand And fingers. Outside this scheme are two muscles: the round pronator and the brachioradialis muscle. From the internal epicondyle of the humerus begins muscle - round pronator, and above the external epicondyle of the humerus begins brachioradialis muscle. The round pronator passes in the upper part of the anterior surface of the forearm and is attached to the radius. He bends And penetrates the forearm. The brachioradialis muscle descends with its tendon to the lower end of the forearm and is attached to the radius above its styloid process. Flexes the forearm, maybe it turn inward And outside. These muscles, with their edges facing each other, are involved in the formation cubital fossa located in the upper part of the anterior surface of the forearm. In this hole, the tendon of the biceps of the shoulder is well palpable.

From the muscles front surface forearm consider ray And ulnar wrist flexors And long palmar muscle.

long palmar muscle has a thin tendon passing to the hand, where it continues in the form palmar aponeurosis. Flexes the brush. Between the tendons of the radial flexor and the wrist of the long palmar muscle is a groove called median.

Flexor carpi ulnaris occupies the most extreme position from the inside, i.e. ulnar side of the anterior surface of the forearm. This muscle is adjacent to the ulna, descends, passes with its tendon to the hand and is attached to the pisiform bone. Flexes the brush.

On dorsal surface of the forearm the following muscles are located: long And extensor carpi radialis brevis, extensor digitorum common, ulnar muscle And ulnar extensor of the wrist. A separate group is made up of muscles that go from the forearm to the thumb.

Rice. 48. Musclesforearms:

A - deep muscles of the anterior group of the forearm, B - superficial muscles of the anterior group of the forearm, C - superficial muscles of the posterior group of the forearm, D - deep muscles of the posterior group of the forearm, E - radius and ulna with interosseous membrane (a - front view, b - rear view):

1 - radial flexor of the wrist, 2 - long palmar muscle, 3 - ulnar flexor of the wrist, 4 - superficial flexor of the fingers, 5 - deep flexor of the fingers, 6 - long flexor of the thumb, 7 - square pronator, 8 - circular pronator, 9 - brachioradialis muscle, 10 - long radial extensor of the wrist, 11 - short radial extensor of the wrist, 12 - extensor of the fingers, 13 - extensor of the little finger, 14 - ulnar extensor of the wrist, 15 - supinator, 16 - longus muscle abductor thumb, 17 - short extensor of the thumb, 18 - long extensor of the thumb, 19 - extensor of the index finger, 20 - short palmar muscle, 21 - shoulder muscle, 22 - biceps muscle.

Rice. 49. Muscles of the hand:

A - palmar aponeurosis and fascia of the forearm, B - tendons of the finger, C - muscles of the hand, D - diagram of the interosseous muscles, D - back of the hand:

1 – short muscle abductor thumb, 2 - short flexor of the thumb, 3 - adductor thumb muscle, 4 - abductor of the little finger, 5 - short flexor of the little finger, 6 - worm-like muscles, 7 - dorsal interosseous muscles, 8 - palmar interosseous muscles, 9 - extensor retinaculum, 10 - palmar aponeurosis, 11 - flexor retinaculum, 12 - flexor of the fingers, 13 - extensor of the fingers.

Attached to the brachioradialis muscle two extensor carpi radialis, long and short. Directly adjacent to the brachioradialis muscle is the muscle extensor carpi radialis longus. With its tendon, it is attached to the base of the dorsal surface of the second metacarpal bone. Muscle extensor carpi radialis brevis attaches to the base of the third metacarpal. Long and short wrist extensors unbend the hand.

Common finger extensor- large muscle With its tendons, it passes to the hand and is attached to the back surfaces of the distal (nail) phalanges of the second to fifth fingers. This muscle unbends fingers and the whole hand.

Rice. 50. Muscles of the hand and the possibilities of its movement:

A - the possibility of movement in the wrist towards the palm and its rear; spreading the fingers to the sides; the possibility of bending the phalanges of the fingers,

B - muscles and tendons of the hand in front and behind, the possibility of movement in the wrist towards the little finger and thumb.

Elbow muscle attached to the dorsum of the ulna. Has the shape of a triangle. Participates in elbow extension. In the region of the external epicondyle and the dorsal surface of the head of the radius, there is a depression between the muscles, which is clearly visible when the arm is extended at the elbow joint. This depression is known as pits of beauty .

Muscles of the hand located on its palmar and dorsal surfaces. On the palmar side there are elevation formed by a group of muscles thumb , elevation belonging to muscles thumb . Between these two muscular elevations is palmar aponeurosis , below it are several muscles of the palm, not to mention the tendons of the flexor muscles of the fingers. The hand has interosseous muscles located between the metacarpal bones. The fossa between the tendons of the muscles going to the first finger of the bone is known as anatomical snuffbox. The functions of the muscles of the hand are varied. They are involved in all finger movements, in particular in bringing And thumb abduction, in his bending, opposition, extension And roundabout. Muscles of the small finger this finger withdraw, bend, oppose. There are also small muscles on the hand - worm-like and interosseous.

Considering the whole hand as a whole, it is easy to verify that it has narrowing in the area of ​​the elbow and wrist joints (where only the tendons of the muscles pass) and extensions over most of the shoulder and in the upper forearm.

Strong forearms are one of the foundations of strength athlete training. Underdeveloped forearms will not allow you to hold a barbell or dumbbells for a long time during the training of the back and biceps, limit the weight in the bench press, etc. In bodybuilding, small forearms look very ugly and will not allow you to take high places at competitions. Forearm training is an integral part of top bodybuilders.

The muscles of the forearm are divided into two groups: the anterior - flexors and pronators (muscles that turn the palm down) and the back - extensors and arch supports (muscles that turn the palm up). The brachioradialis is a muscle that flexes the forearm at the elbow joint. Flexors - muscles located on the inner surface of the forearm, responsible for flexion of the hand and fingers and pronation of the forearm. The extensors are muscles located on outer surface forearms responsible for extension of the hand and fingers and supination of the forearm.

The main functions of the forearm:

1. Extension
2. bending
3. Outward turn (supination)
4. Turn inward (pronation)
5. Brush squeezing

Features of forearm training

Since the forearms are constantly involved both when performing exercises for other muscle groups, and in everyday life, their resistance to stress is quite high. Therefore, they belong to the so-called "difficult" muscles and their development is a rather laborious process.

A set of exercises for the development of the muscles of the forearms should be performed 2 times a week, each exercise in three to four sets, 15-20 repetitions in each set to failure. Before training the forearms, they must be thoroughly warmed up and warmed up in order to prevent injury. It is undesirable to allow full stretching of the muscles at the end points of the amplitude.

As part of a training split, it is best to pump the forearms on the day of the training of the arms and on the day of the back training. You need to train them at the end of the workout, after working out the arms and back, respectively. Otherwise, a full training of the arms and back will be impossible. Between workouts, the forearms should take 2-3 days, otherwise they will not have time to recover, which threatens with chronic pain in the wrist area.