Muscles of the upper limb girdle. Front group.

M. pectoralis major, large pectoral muscle.

2. M. pectoralis minor, pectoralis minor muscle(See “Chest Muscles”).

3. M. coracobrachialis, coracobrachialis muscle, starts from the coracoid process of the scapula along with the short head m. biceps brachii and m. pectoralis minor and is attached to the medial surface of the humerus distal to the crista tuberculi minoris.

Function. Flexes the shoulder and adducts. (Inn. C5-7 N. musculocutaneus.)

Shoulder muscles. Anterior shoulder muscles.

Shoulder muscles

The muscles of the shoulder retain in the simplest form the original arrangement of the muscles of the limbs and are divided according to a classically simple scheme: into two flexors (m. biceps and m. brachials) on the anterior surface (anterior group) and two extensors (m. triceps and so. anconeus) - on the back (posterior group).
They act on the elbow joint, producing movement around the frontal axis, and therefore are located on the front and back surface shoulder, attaching to the bones of the forearm. Both muscle groups are separated from each other by two connective tissue septa, septa intermuscularia brachii, going to the lateral and medial edges of the humerus from the common fascia of the shoulder, which covers all the muscles of the latter.

Anterior shoulder muscles

1. M. biceps brachii, biceps brachii muscle, a large muscle whose contraction is very clearly visible under the skin, thanks to which even people unfamiliar with anatomy know it. The muscle proximally consists of two heads; one (long, caput longum) starts from the tuberculum supraglenoidale of the scapula with a long tendon that passes through the cavity of the shoulder joint and then lies in the sulcus intertubercularis of the humerus, surrounded by the vagina synovialis intertubercularis; the other head (short, caput breve) originates from the processus coracoideus of the scapula.
Both heads, connecting, pass into an oblong fusiform abdomen, which ends in a tendon attached to the tuberositas radii. Between the tendon and the tuberositas radii there is a permanent synovial bursa, bursa bicipitoradialis.
A flat tendon bundle, aponeurosis m., extends from this tendon medially. bicipitis brachii, intertwined with the fascia of the forearm.

Function. Flexes the forearm at the elbow joint; due to its attachment point on the radius, it also acts as an instep support if the forearm has been previously pronated. The biceps muscle extends not only over the elbow joint, but also through the shoulder joint and can act on it, bending the shoulder, but only if the elbow joint is strengthened by contraction m. triceps. (Inn. CV-VII. N. musculocutaneus.)

2. M. brachialis, brachialis muscle, lies deeper than the biceps muscle and originates from the anterior surface of the humerus, as well as from both septa intermuscularia brachii and attaches to the tuberositas ulnae.

Function. Pure forearm flexor. (Inn. C5-7 N. musculocutaneus.)

Forearm muscles. Anterior muscle group of the forearm

Forearm muscles

According to their function, they are divided into flexors and extensors, some of them flex and extend the entire hand, while others - the fingers. In addition, there are also pronators and supinators, which produce the corresponding movements of the radius. According to their position, all these muscles fall into two groups: the anterior one, which includes flexors and pronators, and the posterior one, consisting of extensors and supinators.

Each group is composed of superficial and deep layers. The superficial layer of the muscles of the anterior group originates in the region of the medial epicondyle of the shoulder, the same layer of the posterior group originates in the region of the lateral epicondyle. The deep layer of both groups in its main part no longer finds a place of attachment on the epicondyles, but originates on the bones of the forearm and on the interosseous membrane.
The final attachments of the flexors and extensors of the hand are located at the bases of the metacarpal bones, and the same muscles going to the fingers are attached to the phalanges, with the exception of the long abductor pollicis muscle, which is attached to the first metacarpal bone.

The pronators and supinators are attached to the radius. The muscles of the forearm closer to the shoulder consist of fleshy parts, while towards the hand they turn into long tendons, as a result of which the forearm has the shape of a cone, flattened from front to back.

Muscles of the upper limb. Muscles of the upper limb girdle. Back group.

1. M. deltoideus, deltoid muscle, covers the proximal end of the humerus. It starts from the lateral third of the clavicle and the acromion of the scapula, as well as from the spina scapulae along its entire length. The anterior and posterior muscle bundles run almost straight down and laterally; the middle ones, bending over the head of the humerus, are directed straight down.
All bundles converge and attach to the tuberositas deltoidea in the middle of the humerus. Between the inner surface of the muscle and the greater tubercle of the humerus there is a bursa subdeltoidea.

Function. When the anterior (clavicular) part of the deltoid muscle contracts, the arm flexes; contraction of the posterior (scapular) part produces a reverse movement - extension, extensio. Contraction of the middle (acromial) part or the entire deltoid muscle causes the arm to abduct from the body to a horizontal level. All these movements occur in the shoulder joint. When, due to the shoulder resting on the shoulder arch, the movement in the shoulder joint is inhibited, further raising of the arm above the horizontal level, elevatio, is accomplished with the assistance of the muscles of the upper limb and back girdle, attached to the scapula.
In this case, the upper beams m. trapezius pull the lateral angle of the scapula through the spina scapulae upward and medially, and the lower bundles of m. serratus anterior pull the lower angle upward and laterally, as a result of which the scapula rotates around the sagittal axis passing through its upper angle.
The latter is fixed by contraction of the rhomboid muscle, m. serratus anterior and m. levator scapulae. As a result of rotation of the scapula, the glenoid cavity rises upward, and with it the humerus, held in the same position in relation to the humeral arch by contraction of the deltoid and supraspinatus muscles. (Inn. C5-Th5, N. axillaris.)

2. M. supraspinatus, supraspinatus muscle, lies in the fossa supraspinata of the scapula and is attached to the upper part of the greater tubercle of the humerus. The muscle is covered with strong fascia, fascia supraspinata.

Function. Abducts the hand, being a synergist m. deltoideus (Inn. C5-6, N. suprascapularis.)

3. M. infraspinatus, The infraspinatus muscle performs most of the fossa infraspinata and is attached to the greater tubercle of the humerus.

Function. Supinates the shoulder. (Inn. C5-6 N. suprascapularis.)

4. M. teres minor, teres minor muscle, starts from the margo lateralis of the scapula and attaches to the greater tubercle of the humerus below the tendon of the m. infraspinatus.

Function. Like the previous muscle. (Inn. C5-Th5 N. axillaris.)

5. M. teres major, teres major muscle, starts from the posterior surface of the lower angle of the scapula and is attached along with m. latissimus dorsi to crista tuberculi minors. In humans, it is separated from the subscapularis muscle, maintaining, however, a common innervation with it.

Function. Pulls the arm backward and downward, bringing it to the body, and also rotates it inward. (Inn. CV-VI, N. subscapularis.)

6. M. subscapularis, subscapularis muscle, occupies with its origin the entire fades costalis of the scapula and is attached to the tuberculum minus of the humerus.

Function. Rotates the shoulder inward (pronates), and can also stretch the joint capsule, protecting it from pinching. The above-described muscles attached to the greater tubercle of the humerus also have the latter property due to their fusion with the capsule. (Inn. CV-VI. N. subscapularis.)

7. M. latissimus dorsi, latissimus dorsi(see “Back muscles”).

Table of contents of the topic "Muscles of the upper limb. Muscles of the upper limb girdle. Muscles of the shoulder. Muscles of the forearm.":

Muscles of the upper limb. Muscles of the upper limb girdle. Back group.

1. M. deltoideus, deltoid muscle, covers the proximal end of the humerus. It starts from the lateral third of the clavicle and the acromion of the scapula, as well as from the spina scapulae along its entire length. The anterior and posterior muscle bundles run almost straight down and laterally; the middle ones, bending over the head of the humerus, are directed straight down.

All bundles converge and attach to the tuberositas deltoidea in the middle of the humerus. Between the inner surface of the muscle and the greater tubercle of the humerus there is a bursa subdeltoidea.

Function. When the anterior (clavicular) part of the deltoid muscle contracts, the arm flexes; contraction of the posterior (scapular) part produces a reverse movement - extension, extensio. Contraction of the middle (acromial) part or the entire deltoid muscle causes the arm to abduct from the body to a horizontal level.

All these movements occur in the shoulder joint. When, due to the shoulder resting on the shoulder arch, the movement in the shoulder joint is inhibited, further raising of the arm above the horizontal level, elevatio, is accomplished with the assistance of the muscles of the upper limb and back girdle, attached to the scapula.

In this case, the upper beams m. trapezius pull the lateral angle of the scapula through the spina scapulae upward and medially, and the lower bundles of m. serratus anterior pull the lower angle upward and laterally, as a result of which the scapula rotates around the sagittal axis passing through its upper angle.

The latter is fixed by contraction of the rhomboid muscle, m. serratus anterior and m. levator scapulae. As a result of rotation of the scapula, the glenoid cavity rises upward, and with it the humerus, held in the same position in relation to the humeral arch by contraction of the deltoid and supraspinatus muscles. (Inn. C5-Th5, N. axillaris.)

2. M. supraspinatus, supraspinatus muscle, lies in the fossa supraspinata of the scapula and is attached to the upper part of the greater tubercle of the humerus. The muscle is covered with strong fascia, fascia supraspinata.

Function. Abducts the hand, being a synergist m. deltoideus (Inn. C5-6, N. suprascapularis.)

3. M. infraspinatus, The infraspinatus muscle performs most of the fossa infraspinata and is attached to the greater tubercle of the humerus.

Function. Supinates the shoulder. (Inn. C5-6 N. suprascapularis.)

4. M. teres minor, teres minor muscle, starts from the margo lateralis of the scapula and attaches to the greater tubercle of the humerus below the tendon of the m. infraspinatus.

Function. Like the previous muscle. (Inn. C5-Th5 N. axillaris.)

5. M. teres major, teres major muscle, starts from the posterior surface of the lower angle of the scapula and is attached along with m. latissimus dorsi to crista tuberculi minors. In humans, it is separated from the subscapularis muscle, maintaining, however, a common innervation with it.

Function. Pulls the arm backward and downward, bringing it to the body, and also rotates it inward. (Inn. CV-VI, N. subscapularis.)

6. M. subscapularis, subscapularis muscle, occupies with its origin the entire fades costalis of the scapula and is attached to the tuberculum minus of the humerus.

Function. Rotates the shoulder inward (pronates), and can also stretch the joint capsule, protecting it from pinching. The above-described muscles attached to the greater tubercle of the humerus also have the latter property due to their fusion with the capsule. (Inn. CV-VI. N. subscapularis.)

Muscles of the shoulder girdle. The shoulder girdle, which strengthens the free limb on the body, is connected to it by only one sternoclavicular joint. Strengthening the shoulder girdle is carried out by muscles originating on the torso (chest muscles, back muscles).

Muscles of the shoulder girdle and shoulder, right. A - B - front view; G - rear view; 1 - pectoralis minor muscle (m. pectoralis minor); 2 - biceps brachii (m. biceps brachii); 3 - coracobrachial muscle (m. coracobrachial); 4 - brachial muscle (m. brachialis); 5 - teres major muscle (m. teres major); 6 - subscapularis muscle (m. subscapularis); 7 - supraspinatus muscle (m. supraspinatus); 8 - infraspinatus muscle (m. infraspinatus); 9 - teres minor muscle (m. teres minor); 10 - triceps brachii muscle (m. triceps brachii)

The muscles covering the own chest muscles are powerfully developed in humans. They move and strengthen the upper limbs on the body. These muscles include big And small chest, anterior serratus.

Pectoralis major muscle originates from the sternal part of the clavicle, from the edge of the sternum and from the cartilages of the upper 5-6 ribs. The muscle is attached to the crest of the greater tubercle of the humerus. Between the latter and the muscle tendon lies the synovial bursa. By contracting, the muscle adducts and pronates the shoulder, pulling it forward.

Pectoralis minor muscle located under the big one. It starts from the II-V ribs, attaches to the coracoid process and, when contracted, pulls the scapula down and forward.

Serratus anterior muscle begins with nine teeth on ribs II-IX. It is attached to the medial edge of the scapula and to its lower angle, to which most of its bundles are connected. When contracted, the muscle pulls the scapula forward and its lower angle outward, due to which the scapula rotates around the sagittal axis and the lateral angle of the bone rises. If the arm is abducted, the serratus anterior muscle, rotating the scapula, raises the arm above the level of the shoulder joint. Now the arm moves with the shoulder girdle at the sternoclavicular joint.

Back muscle group, associated with the upper limbs, is located in two layers. In the surface layer lie trapezius muscle(visceral) and latissimus dorsi muscle- parietal.

Superficial back muscles: left - first layer; on the right - second layer

Trapezius muscle originates from the superior nuchal line of the occipital bone, the nuchal ligament and the spinous processes of all thoracic vertebrae. The muscle fibers converge outward and attach to the outer end of the clavicle, to the spine and acromial process of the scapula. The lower muscle bundles, contracting, lower the shoulder girdle, the middle ones pull it towards the spine, the upper ones lift it; the superior bundles work as synergists of the serratus anterior muscle when it abducts the arm above the level of the shoulder joint. With a fixed shoulder girdle, the trapezius muscle pulls the head back.

Latissimus dorsi muscle starts from the thoracolumbar fascia, from the spinous processes of the 4-6 lower thoracic vertebrae and all lumbar, 4 lower ribs and the iliac crest. The muscle fibers converge outward and upward, where they are attached by a flat tendon to the crest of the lesser tubercle of the humerus. Between the tendon and the tubercle lies the bursa. The muscle adducts the arm, pronates and pulls it back.

Under the trapezius muscle, therefore in the second layer, lie rhomboid muscle And levator scapula muscle.

Deep back muscles: on the left - lumbodorsal fascia and serratus posterior muscles; on the right - I and II tracts of the deep back muscles

Rhomboid muscle starts from the spinous processes of the two lower cervical vertebrae and four upper thoracic vertebrae, attaches to the medial edge of the scapula, which is pulled medially and upward during contraction.

Levator scapulae muscle, starts from the transverse processes of the upper cervical vertebrae and attaches to the upper corner of the scapula, which, during its contraction, pulls upward, while simultaneously lowering its lateral corner.

Muscles of the upper limb, located on the body, in addition to the described meaning, have another. So, the muscles attached to the scapula not only move it. With the simultaneous contraction of antagonistic muscle groups, they fix the scapula. In addition, if a limb is immobilized by the tension of other muscles, then when they contract, they no longer act on the limb, but on the chest, expanding it, i.e., they function as auxiliary muscles of inspiration.

Muscles located on the shoulder girdle itself which move and fix the free upper limb in the shoulder joint - these are deltoid, supraspinatus, infraspinatus, small round, big round And subscapularis muscle.

Chest muscles

Muscles of the chest and abdomen

Deltoid together with the ball-shaped shoulder joint, it determines the rounded shape of the human “shoulder”. The muscle starts from the acromial end of the clavicle, the crest and acromial process of the scapula, and is attached to the deltoid roughness of the humerus. Under the muscle there is a synovial bursa, sometimes communicating with the cavity of the shoulder joint. The front muscle bundles, contracting, take part in flexing the arm in the shoulder joint, the rear ones - in its extension, and the middle and the entire muscle as a whole abduct the arm to a horizontal position, after which the humerus rests against the shoulder arch and movement in the joint is inhibited.

Supraspinatus muscle It starts from the supraspinatus fossa of the scapula and the dense fascia covering it, and is attached to the top of the greater tubercle of the humerus. This muscle is synergistic with the deltoid, but is capable of abducting only the unloaded arm, although more quickly.

Infraspinatus muscle It starts from the infraspinatus fossa of the scapula and from the dense fascia covering the muscle, and is attached to the greater tubercle of the humerus. The muscle rotates the shoulder outward.

Teres minor muscle lies under the previous one. It starts from the lateral edge of the scapula and attaches to the greater tubercle of the humerus; works as a synergist of the infraspinatus muscle.

Teres major muscle starts from the lower angle of the scapula, attaches together with the latissimus dorsi muscle to the crest of the lesser tubercle of the humerus. The muscle rotates the shoulder inward.

Subscapularis muscle starts from the entire costal surface of the scapula, attaches to the lesser tubercle of the humerus. Under the muscle lies a small synovial bursa, protruding from the cavity of the shoulder joint. The muscle rotates the shoulder inward.

The supraspinatus, infraspinatus, teres minor and subscapularis muscles, located in close proximity to the shoulder joint, fuse with its bursa. By contracting, they tighten the bag and prevent it from pinching.

Muscles of the shoulder and shoulder blade: A - front; B - behind

Shoulder muscles. There are two muscle groups located in the shoulder area: front(consists of flexors) and back(consists of arm extensors in the shoulder and elbow joints). These muscles are surrounded by the fascia of the shoulder, which forms separate sheaths around each group, which are separated by intermuscular septa. The latter extend deep from the fascia of the shoulder, where they fuse with humerus.

Front group educated coracobrachial, double-headed And brachialis muscles, A back - triceps And ulnar.

Coracobrachialis muscle, starting from the coracoid process, attached to the anterior surface middle third shoulder, bends the arm at the shoulder joint.

Biceps with its short head it begins together with the coracohumeral from the coracoid process. The long head originates inside the joint cavity from the supraglenoid tuberosity of the scapula. Having passed through the bursa, the tendon of the long head lies in the intertubercular groove, surrounded by a process of the synovial layer of the bursa, due to which the tightness of the joint is not broken. Below, both heads are connected. Spreading over the elbow joint, the muscle attaches to the tuberosity of the radius; here between the tendon and the tuberosity there is a synovial bursa. Some of the tendon fibers are woven into the fascia of the forearm and significantly strengthen it. The muscle flexes the arm at the shoulder and elbow joints and supinates the forearm.

Brachialis muscle starts from the lower two thirds of the anterior surface of the humerus, from the medial and lateral intermuscular septa, and is attached to the tuberosity of the ulna. The muscle flexes the forearm.

Triceps, located on the dorsum of the shoulder, works as an antagonist of the muscles of the anterior group. Of the three heads of the muscle, the long one originates from the subarticular tuberosity of the scapula; the lateral (more powerful) and medial (weaker) heads start from the back of the humerus and intermuscular septa, located on the sides of the long head. The muscle is attached by a common tendon to the olecranon process of the ulna. The triceps muscle extends the arm at the elbow joint, and its long head also extends at the shoulder joint.

The olecranon process remains uncovered by muscles; between it and the skin there is a subcutaneous synovial bursa.

Ulnar muscle is small, triangular; starting from the outer epicondyle of the humerus, it goes obliquely inward, covered by the dense fascia of the forearm, from which it partially begins; attaches to the posterior edge of the ulna. The muscle, like the triceps, extends the arm at the elbow joint, but faster and without load. Fusing with the bursa of the elbow joint, the muscle retracts it.

Forearm muscles. In the forearm area there are two muscle groups: front And rear. The first contains the flexors and pronators; in the second - extensors and supinators.

All these muscles are covered by the common fascia of the forearm, which forms a dense sheath around them, which extends deep into the intermuscular septa that separate the anterior and posterior groups. The muscles adjacent to them begin from the septa, as well as from the fascia itself. Moving from the forearm to the hand, especially compacted areas of the fascia form ligaments - the flexor retinaculum and the extensor retinaculum.

Distal to the flexor retinaculum, the fascia thickens into the transverse ligament, which adheres to the edges of the carpal arch, turning it into the carpal tunnel. Under all these ligaments, the tendons of the forearm muscles pass to the hand.

In both the anterior and posterior groups, the muscles are located in two layers - superficial and deep.

IN superficial layer of the anterior group the muscles lie, starting from the radial edge of the forearm, in the following order: pronator teres, flexor carpi radialis, palmaris longus muscle, flexor digitorum superficialis, flexor carpi ulnaris. They all originate from the medial epicondyle of the humerus, fascia and medial intermuscular septum.

Anterior muscle group of the forearm: A - superficial and B - deep layers. Synovial tendon sheaths are shown in blue.

Pronator teres goes obliquely downwards and is attached to the anterior outer surface of the middle third of the diaphysis of the radius. The muscle pronates the forearm, that is, it rotates the radius bone and the hand connected to it inward.

In this case, the radius crosses the ulna bone, which remains motionless, in front, and the hand turns its palmar surface back.

Flexor carpi radialis located obliquely, attached to the base of the second metacarpal bone. The muscle flexes the hand and partially pronates the forearm.

Palmaris longus muscle rudimentary and may be absent. It has a small abdomen and a long tendon, which expands and passes into a wide palmar aponeurosis, which fuses with the skin of the palm. It strains the skin of the palm and participates in the flexion of the hand.

Flexor digitorum superficialis has a wide muscle belly, which in the lower half of the forearm turns into four tendons; having passed through the carpal canal, each of them bifurcates and is attached with two legs to the lateral surface of the middle phalanges of the II-V fingers. The muscle flexes the middle phalanges and is involved in flexion of the hand.

Flexor carpi ulnaris, covering the pisiform bone with its tendon, it is attached to the base of the fifth metacarpal bone. The muscle flexes the hand.

In addition to these functions, all the muscles of the superficial layer of the forearm flex the elbow joint.

TO deep layer muscles anterior group include flexor pollicis longus, flexor digitorum profundus And pronator quadratus.

Flexor pollicis longus lies in the deep layer most laterally. The muscle starts from the anterior surface of the radius and attaches to nail phalanx thumb and bends it, as well as the entire finger.

Flexor digitorum profundus starts from the anterior surface of the ulna and the interosseous membrane. Divided into four tendons, it exits onto the hand through the carpal canal and attaches to the nail phalanges of the II-V fingers, having previously passed between the tendon legs of the superficial flexor digitorum. The muscle flexes the nail phalanges and partly the hand.

Pronator quadratus lies in the distal part of the forearm, directly on the bones. It starts from the anterior surface of the ulna and attaches to the anterior outer surface of the radius. The muscle is a synergist of the pronator teres.

From superficial layer of the posterior group those lying along the radius are especially prominent brachioradialis muscle, long And extensor carpi radialis brevis, united in the palmar complex of the muscles of the forearm.

Posterior muscle group of the forearm: A - superficial layer and B - its lateral complex. Synovial tendon sheaths are shown in blue.

Brachioradialis muscle starts from the lateral surface of the humerus, spreads over the elbow joint, runs along the radius and attaches to its styloid process. The muscle supinates the forearm, which is in a pronated state (which is why it was previously called the long supinator), and pronates the supinated forearm. As a result of tension in the brachioradialis muscle, the arm finds itself in an intermediate, neutral position - with the palm facing the body. The muscle also flexes the arm at the elbow joint.

The long and short extensor carpi radialis originate first from the humerus immediately above the lateral epicondyle; the second - from the epicondyle itself; the long one is attached to the base of the II, the short one - to the base of the III metacarpal bone. The muscles extend the hand.

Rest muscles of the superficial layer of the posterior group originate from the external epicondyle of the humerus. These include finger extensors And extensor carpi ulnaris.

Extensor digitorum, located along the forearm, is divided into four tendons, heading towards the back of the II-V fingers, where they turn into wide tendon stretches. On the hand, the tendons are connected to each other by jumpers. The muscle extends the fingers and hand.

Extensor carpi ulnaris attaches to the base of the fifth metacarpal bone. He straightens his wrist.

Muscles of the superficial layer, starting from the lateral epicondyle of the humerus, in addition to the indicated functions, extend the arm at the elbow joint.

The flexors and extensors of the wrist of the same name, throwing themselves over the biaxial wrist joint, can working together perform radial or ulnar abduction. For example, the simultaneous contraction of the elbow flexor and extensor muscles causes abduction of the hand to the medial side. In these cases, the antagonists turn out to be synergists.

To the muscles deep layer of the posterior group include arch support, thumb muscle complex and own extensor index finger.

Arch support starts from the external epicondyle of the humerus and a special crest of the ulna, goes obliquely through the forearm and attaches to the outer and palmar surfaces of the radius. The muscle supinates the forearm and hand, that is, it rotates them outward so that the palm turns forward.

Three muscles that move the thumb, originate from the distal third of the posterior surface of the radius and ulna bones and from the interosseous membrane. The abductor pollicis longus muscle is attached to the base of the first metacarpal bone and abducts the thumb, as well as the hand; the short extensor pollicis attaches to the base of its first (proximal) phalanx, extends and abducts the thumb; The extensor pollicis longus attaches to its nail phalanx and straightens the finger.

Extensor index finger starts from the posterior surface of the ulna and the interosseous membrane; its distal tendon fuses with the tendon for this finger from the extensor digitorum. Thanks to the presence of its own muscle, the index finger can extend independently, while separate extension of the remaining fingers is difficult, especially since their tendons are connected by intermediate bridges.

Muscles of the hand. The fascia on the hand is especially powerfully developed in the middle part of the palm, where the tendon fibers of the palmaris longus muscle are woven into it and the palmar aponeurosis is formed. The tendons of the superficial and deep digital flexors pass under the aponeurosis. From the four tendons of the latter, small worm-shaped muscles originate, attaching to the tendon stretch on the back of the II-V fingers. The muscles flex the fingers at the metacarpophalangeal joints and extend them at the interphalangeal joints.

Muscles of the hand, right. A - palmar surface: 1 - pronator quadratus (m. pronator quadratus); 2 - short muscle that abducts the thumb (m. abductor pollicis brevis); 3 - short flexor pollicis brevis (m. flexor pollicis brevis); 4 - muscle opposing the thumb (m. opponens pollicis); 5 - muscle that adducts the thumb (m. adductor pollicis); 6 - short palmaris muscle (m. palmaris brevis); 7 - muscle that abducts the little finger (m. abductor digiti minimi); 8 - short flexor of the little finger (m. flexor digiti minimi brevis); 9 - muscle opposing the little finger (m. opponens digiti minimi); 10 - flexor carpi radialis tendon; 11 - flexor carpi ulnaris tendon. B - dorsal surface: 1 - palmar interosseous muscles (mm. interossei palmares); 2 - dorsal interosseous muscles (mm. interossei dorsales)

The lateral eminence of the palm is formed by the short muscles of the thumb: abductor brevis muscle, short flexor, oppons pollicis muscle, And adductor muscle. Thus, the thumb has its own muscular apparatus in the palm, which significantly increases and diversifies its movements.

On the medial side of the palm there is a slightly smaller elevation formed by the muscles of the little finger: diverting, opposing And short flexor. They are less developed than the short muscles of the thumb and are sometimes not differentiated from each other.

In the space between the metacarpal bones there are interosseous muscles: three on the side of the palm (add the fingers towards each other) and four on the side of the back of the hand (spread the fingers).

On the fingers, the palmar aponeurosis thickens and, fused with the periosteum of the phalanges, forms fibrous sheaths of the fingers. The tendons of the muscles that flex the fingers slide in the latter. Tendons are surrounded synovial vaginas. These are connective tissue sheaths that surround muscle tendons, promoting their gliding and reducing friction, as well as localizing inflammatory processes.

Chest muscles(A - front view. B - pectoralis major muscle removed). 1 - deltoid muscle (m. deltoideus); 2 - pectoralis major muscle (m. pectoralis major); 3 - external oblique abdominal muscle (m. obliquus externus abdominis); 4 - serratus anterior muscle (m. serratus anterior); 5 - subclavian muscle (m. subclavius); 6 - internal intercostal muscles (mm. intercostales interni); 7 - pectoralis minor muscle (m. pectoralis minor); 8 - latissimus dorsi (m. latissimus dorsi)

Muscles of the chest and abdomen. 1 - pectoralis minor muscle (m. pecforalis minor); 2 - internal intercostal muscles (mm. intercostales interni); 3 - external intercostal muscles (mm. intercostales externi); 4 - rectus abdominis muscle (m. rectus abdominis); 5 - internal oblique abdominal muscle (m. obliquus internus abdominis); 6 - transverse abdominal muscle (m. transversus abdominis); 7 - external oblique abdominal muscle (m. obliquus externus abdominis); 8 - aponeurosis of the external oblique abdominal muscle; 9 - serratus anterior muscle (m. serratus anterior); 10 - pectoralis major muscle (m. pectoralis major); 11 - deltoid muscle (m. deltoideus); 12 - subcutaneous muscle of the neck (platysma)

Description of areas
The upper limb girdle and upper limb have areas: deltoid (regio deltoidea); acromial (regio acromialis); shoulder, anterior and posterior (regio brachii anterior et posterior); ulnar, anterior and posterior (regio cubiti anterior et posterior); cubital fossa (fossa cubitalis); forearm area, anterior and posterior (regio antebrachii anterior et posterior); wrists, anterior and posterior (regio carpi anterior et posterior); metacarpus, palmar and dorsal (regio metacarpi volaris et dorsalis); fingers, anterior and posterior (regio digitorum manus anterior et posterior).

Muscles of the upper limb girdle
The muscles of the bones of the upper limb girdle connect the scapula and collarbone with the bones of the torso and the humerus.

This section outlines the structure and function of 6 muscles lying in two layers: superficial and deep.

187. Muscles of the right girdle of the upper limb and shoulder.

1 - m. levator scapulae (part);
2 - m. supraspinatus;
3 - spina scapulae;
4 - tuberculum majus humeri;
5 - m. deltoideus (part);
6 - caput laterale m. triceps brachii;
7 - caput longum m. triceps brachii;
10 - m. teres major;
11 - m. teres minor;
12 - m. infraspinatus;
13 - m. rhomboideus major;
14 - m. rhomboideus minor.

Superficial muscles of the upper limb girdle
The deltoid muscle (m. deltoideus) is located on top of the shoulder joint, has the shape of a triangle with the apex facing the humerus (Fig. 187). The anterior edge of the deltoid muscle along with m. pectoralis major forms a groove - sulcus deltoideopectoralis. The deltoid muscle originates from the lateral third of the clavicle, the acromion of the crest of the scapula and f. infraspinata. Attached to the tuberositas deltoidea, located on the lateral upper third of the humerus. The muscle consists of large bundles separated by connective tissue layers of the deltoid fascia. Between the deep layer of the deltoid fascia and the greater tubercle of the humerus there is a mucous bursa (bursa subdeltoidea).

Innervation: n. axillaris (C (IV-VI)).

Function. The anterior bundles of the deltoid muscle are involved in flexion of the shoulder joint, the posterior bundles are involved in extension of this joint, and the middle bundles are involved in abduction of the upper limb up to 70°. Further movement is impossible due to the emphasis of the greater tubercle on the lig. coracoacromiale. Raising the arm above 70° occurs in the sternoclavicular joint with simultaneous rotation of the scapula with the humerus pressed against it, contraction of the upper bundles of the trapezius and serratus anterior muscles.

Deep muscles of the upper limb girdle
The supraspinatus muscle (m. supraspinatus) starts from the supraspinatus fossa of the scapula and the supraspinatus fascia, then passes under the acromion and is attached to the anterior part of the greater tubercle of the humerus and the articular capsule. The muscle is covered from above by the front part of m. trapezius.

Function. Together with the deltoid muscle, it participates in shoulder abduction.

The infraspinatus muscle (m. infraspinatus) originates from a significant part of the infraspinatus fossa of the scapula and the infraspinatus fascia. Attaches to the middle part of the greater tubercle of the humerus and the articular capsule.

Innervation: n. suprascapularis (CV-VI).

Function. Rotates the shoulder outward.

The teres minor muscle (m. teres minor) starts from the lateral edge of the scapula and the infraspinatus fascia and is attached to the back of the greater tubercle of the humerus. In some cases, the tendon fuses with m. infraspinatus.

Innervation: n. axillaris (CV-VI).

Function. Together with the previous muscle, it is involved in turning the shoulder outward.

The teres major muscle starts from the posterior surface of the lower angle of the scapula and is attached to the crest of the lesser tubercle of the humerus. It is located below the teres minor muscle and in front of the long head of the triceps brachii muscle.

Function. Participates in inward rotation of the shoulder, pulling it back and bringing it closer to the body.

Between the muscles of the scapula there are gaps filled with fiber, blood vessels and nerves. The trilateral foramen (for. trilaterum) is located between the teres minor and major muscles and the long head of the triceps brachii muscle. The quadrilateral foramen (for. quadrilaterum) is limited superiorly by the teres minor, anteriorly by the teres major, the lateral humerus, and the medially long head of the triceps brachii muscle.

The subscapularis muscle (m. subscapularis) starts from the costalis scapulae and the subscapularis fascia, attaches to the lesser tuberosity of the humerus and the articular capsule. At the site of contact of the tendon with this capsule there is a mucous bursa.

Innervation: n. subscapularis (CV-VII).

Function. Rotates the shoulder inward and leads to the body.