Muscles of the upper limb: classification, structure, functions. Muscles of the human upper limbs: structure and functions Muscles of the girdle of the upper limb begin on the bones
muscles upper limb divided into muscles shoulder girdle and muscles of the free upper limb: shoulder, forearm and hand.
Muscles of the shoulder girdle
Covering almost all sides of the shoulder joint, they are located in two layers: in the superficial layer lies deltoid; in the deep - the rest of the muscles.
Deltoid muscle, m. deltoideus, has a triangular shape, lies superficially, covering the shoulder joint from almost all sides. It starts from the lateral third of the clavicle, the acromial process and the spine of the scapula; attaches to the deltoid tuberosity of the humerus. Function: draws the hand into shoulder joint.
Supraspinatus muscle, m. supraspinatus, begins in the same-named fossa of the scapula, passes under the acromion and attaches to the large tubercle of the humerus Function: abducts the shoulder.
Infraspinatus muscle, m. infraspinatus, starts from the infraspinatus fossa of the scapula; attached to the greater tubercle of the humerus. Function: rotates the shoulder outward.
Small round muscle, m. teres minor, adjacent from below to the infraspinatus muscle; attached to the greater tubercle of the humerus. Function: rotates the shoulder outward.
Large round muscle, m. teres major, starts from the dorsal surface of the scapula at its lower angle, adjacent to the tendon latissimus dorsi back and is attached to the crest of the lesser tubercle of the humerus. Function: leads the shoulder, rotates it inward.
Subscapularis muscle, m. subscapularis, fills the fossa of the same name, attaches to the lesser tubercle of the humerus. Function: leads the shoulder, rotates it inward.
Shoulder muscles
The muscles of the shoulder are divided into two groups according to their location - the anterior (flexors) and the posterior (extensors). The front group includes biceps shoulder, coracobrachial and shoulder muscles; in the rear group triceps shoulder and ulnar muscle.
Anterior group of muscles of the shoulder.
The biceps muscle of the shoulder, m. biceps brachii, has two heads. The long head starts from the supraarticular tubercle of the scapula, passes through the cavity of the shoulder joint. The short head originates from the coracoid process of the scapula. Both heads are connected to a common abdomen, the tendon of which is attached to the tuberosity of the radius Function: flexes the shoulder, flexes the forearm.
Coracobrachial muscle, m. coracobrachialis, also starts from the coracoid process of the scapula. Attached to the humerus in its upper third. Function: flexes the shoulder.
Shoulder muscle, m. brachialis, lies under the biceps of the shoulder. It starts from the anterior surface of the lower and middle third of the humerus; attached to the tuberosity of the ulna. Function: performs flexion in the elbow joint.
Back muscle group of the shoulder.
Triceps muscle of the shoulder, m. triceps brachii, occupies the entire back surface of the shoulder, has three heads: long, lateral and medial. The long head starts from the subarticular tubercle of the scapula. The lateral head starts from the posterolateral surface of the humerus in its middle third. The medial head starts from the humerus in the region of its lower third. All heads are connected into one tendon, which is attached to the olecranon of the ulna. Function: performs extension in the shoulder and elbow joints. Elbow muscle, m. anconeus, grows together with the previous one. It originates from the lateral epicondyle of the humerus and inserts on the olecranon of the ulna. Function: performs extension in the elbow joint.
Muscles of the forearm
The muscles of the forearm act on several joints: the elbow, wrist, joints of the hand and fingers. According to the topography, the muscles of the forearm are divided into two groups - anterior and posterior; each has two layers - deep and superficial. Classification of the muscles of the forearm.
1. Front group:
a) superficial layer: brachioradialis muscle, pronator round, radial flexor of the wrist, long palmar muscle, superficial flexor of the fingers, ulnar flexor of the wrist;
b) deep layer: long flexor thumb, deep flexor of fingers, square pronator.
2. Back group:
a) superficial layer: long and short radial extensor of the wrist, extensor of the fingers, extensor of the little finger, ulnar extensor of the wrist;
b) deep layer: supinator muscle; long muscle that abducts the thumb of the hand; short extensor of the thumb; long extensor of the thumb; index finger extensor.
In function, the anterior group of muscles of the forearm are flexors (seven muscles) and pronators (two muscles); rear group- these are the extensors (nine muscles) and one arch support. Most of the flexors originate from the medial epicondyle of the humerus; most of the extensors originate from the lateral epicondyle of the humerus.
Anterior group of muscles of the forearm.
surface layer.
Shoulder muscle, m. brachioradialis, begins above the lateral epicondyle of the humerus and is attached to the lower end of the radius Function: performs flexion in the elbow joint; sets the brush in the middle position between supination and pronation.
Round pronator, m. pronator teres, starts from the medial epicondyle of the humerus and is attached to the middle of the radius. Function: pronates the forearm, participating in its flexion in the elbow joint.
Radial flexor of the wrist, m. flexor carpi radialis, starts from the medial epicondyle of the humerus and is attached to the base of the second metacarpal bone. Function: flexes the hand, participates in its abduction. Long palmar muscle, m. palmaris longus, inconstant, starts from the medial epicondyle of the humerus, has a small abdomen and a long narrow tendon that is woven into the palmar aponeurosis. Function: strains the palmar aponeurosis, flexes the hand.
Superficial flexor of fingers, m. flexor digitorum superficialis, starts from the medial epicondyle of the humerus, the coronoid process of the ulna, and also from the upper part of the radius. The muscular abdomen is divided into four tendons, and each of them into two legs and is attached to the lateral surfaces of the middle phalanges of the II-V fingers. Function: bends the hand, as well as II - V fingers.
Elbow flexor of the wrist, m. flexor carpi ulnaris, has two heads: the first starts from the medial epicondyle of the humerus, the second - from the olecranon of the ulna; attached to the pisiform bone. Function: bends the brush and leads it.
Deep layer.
The long flexor of the thumb originates from the radius and the interosseous membrane of the forearm; attached to the base of the nail phalanx of the thumb. Function: flexes the thumb as well as the hand.
The deep flexor of the fingers, starts from the ulna and the interosseous membrane of the forearm, is divided into four tendons that pass between the tendons of the superficial flexor of the fingers and are attached to the nail phalanges of the II-V fingers. Functions: bends II-V fingers and hand.
Square pronator, m. pronator quadratus, lies under the flexor tendons. It originates from the lower third of the ulna and inserts on the distal third of the radius. Function: rotates inward (pronates) the forearm and hand.
Posterior muscle group of the forearm.
surface layer.
The long and short radial extensors of the wrist, located superficially, start from the lateral epicondyle of the humerus. In the middle of the forearm, they pass into tendons and are attached: a long extensor - to the base of the II metacarpal, a short one - to the base of the III metacarpal bones. Function: unbend the forearm, unbend and abduct the hand.
Finger extensor, m. extensor digitorum, starts from the lateral epicondyle of the humerus, is divided into four tendons, which are attached to the back of the middle and nail phalanges of the II-V fingers. At the level of the heads of the metacarpal bones, the tendons are connected by obliquely oriented bundles - intertendon joints. Function: unbends II-V fingers and hand.
Extensor of the little finger, m. extensor digiti minimi, has a common origin with the extensor of the fingers; attached to the base of the middle and nail phalanges of the little finger. Function: extends the little finger. Elbow extensor of the wrist, m. extensor carpi ulnaris, starts from the lateral epicondyle of the humerus; attached to the base of the fifth metacarpal bone. Function: unbends and leads the brush.
Deep layer.
Arch support, m. supinator, completely covered by superficial muscles. It starts from the lateral epicondyle of the humerus, covers the radius from behind and from the side; attached to the proximal third of the radius. Function: supinates the forearm together with the hand.
The long muscle that abducts the thumb of the hand, m. abductor pollicis longus, starts from the ulna and radius, as well as the interosseous membrane of the forearm; attached to the base of the I metacarpal bone. Function: abducts the thumb and hand.
Short extensor of the thumb, m. extensor pollicis brevis, starts from the radius and the interosseous membrane of the forearm; attached to the proximal phalanx of the thumb. Function: unbends the proximal phalanx, abducts the thumb.
Long extensor of the thumb, m. extensor pollicis longus, starts from the ulna and the interosseous membrane of the forearm; attached to the base of the distal phalanx of the thumb. Function: extends the thumb of the hand.
Extensor of the index finger, m. extensor indicis, starts from the ulna and the interosseous membrane of the forearm; attached to the proximal phalanx of the index finger. Function: extends the index finger.
Muscles of the hand
The muscles of the hand are located only on the palmar side. On the dorsal surface, only the extensor tendons pass. The muscles of the hand are divided into three groups according to their location: lateral (muscles of the thumb), forming a well-defined elevation of the thumb - tenar; medial (muscles of the little finger), forming the elevation of the little finger - the hypothenar; middle group muscles of the hand, which corresponds to the palmar depression.
1. Lateral group - thenar muscles perform movements according to their names, the muscle that removes the thumb; short flexor of the thumb; muscle that opposes the thumb of the hand; adductor thumb muscle.
2. Medial group - muscles of the hypothenar: short palmar muscle; muscle that removes the little finger; short little finger flexor; muscle that opposes the little finger. These muscles fix the little finger and carry out its flexion, abduction and opposition.______________________________________________________________
Another variant!!! The composition of the structure includes: Skin. Muscles. Bone skeleton. Blood vessels. Bundles
Anatomy of the musculature Fibers are divided into two types. The first is the musculature shoulder girdle, to the second - free part. Classification is carried out depending on the tasks performed and the location. Muscles of the upper limbs the areas of the shoulder girdle are divided into deltoid, supra- and infraspinatus, small and large round, as well as subscapular fibers. The composition of the shoulder girdle includes the muscles of the hand, shoulder and forearm.
Large round fibers They have an elongated flat shape. Start from the back of the lower angle on the shoulder blade. These muscles of the upper limbs are fixed on a small tubercle in the humerus (on the crest). The posterior calving is adjacent to the broad fibers of the back. The large round muscles of the upper limbs, when contracted, pull the shoulder back, turning it inward. As a result, the arm returns to the body.
deltoid fibers They are presented in the form of a triangle. Under bottom this muscle of the upper limbs are subdeltoid bags. The fibers cover the shoulder joint completely and the muscles of the shoulder locally. The deltoid muscle includes large bundles converging at the top. They are divided according to tasks. The back pulls the arm back, the front pulls it forward. The fibers begin from the axis of the scapula (lateral end) and part of the clavicle. The site of fixation is the deltoid tuberosity in the humerus. The deltoid muscles of the upper limbs abduct the shoulders outward until they assume a horizontal position.
Small round fibers They make up an oblong rounded muscle. Its anterior part is covered by deltoid fibers, the posterior part by large round ones. The muscle starts from the scapula, slightly below the infraspinatus fibers, to which its upper surface adjoins. The segment is attached to the platform on the tubercle of the humerus and the joint capsule (to its back). The muscle turns the shoulder outward, retracts and retracts the joint capsule.
Supraspinous fibers They form a trihedral muscle. It is located in the supraspinatus fossa under the trapezoidal segment. The place of fixation is the posterior part of the shoulder joint capsule and the platform on the large tubercle of the bone. The muscle begins on the surface of the fossa. When the fibers contract, the shoulder rises and the joint capsule is pulled back, which prevents pinching.
Subscapular fibers They form a triangular wide flat muscle. The fibers are located in the subscapular fossa. At the attachment site there is a tendon bag. The muscle begins on the subscapular fossa, and ends in a small tubercle in the humerus and on the front of the joint capsule. Due to the contraction of the fibers, the shoulder rotates inward.
Infraspinatus fibers They form a flat triangular muscle. The segment is located in the infraspinatus fossa. The beginning of the fibers is located on its wall and the posterior scapular part. It is fixed to the capsule in the shoulder joint and to the middle area on the large tuberosity of the bone, under which the tendon bag is located. When contracting, the muscle turns the shoulder outward, allows the raised arm to be abducted, and retracts the joint capsule.
Musculature of the shoulder It is divided into two groups. The anterior one performs flexion, and the posterior one performs extension of the shoulder and forearm. The first group includes the biceps, shoulder and coracoid muscles. The composition of the second section includes the triceps and ulnar muscles of the human upper limbs.
biceps fibers They form a spindle-shaped rounded muscle. It consists of two heads: a short one, which performs arm adduction, and a long one, which produces abduction. The latter starts from the supraarticular tubercle of the scapula. The short head departs from the coracoid process. At the place of their connection, the abdomen is formed. It attaches to the tubercle on the radius. In the medial direction there are several fibrous bundles. They form a lamellar process - aponeurosis. Then it passes into the shoulder fascia. The tasks of the biceps muscle are external rotation and flexion of the forearm at the elbow.
Coracoid fibers They form flat muscle. It is covered by a short head of a two-headed segment. The coracoid muscles of the upper extremities of a person begin at the top of the same-named process of the scapula. Attached fibers below the center of the medial part of the humerus. Due to their contraction, the shoulder rises, the hands are brought to the midline.
shoulder fibers They form a wide fusiform muscle. Its beginning is the anterior and outer surfaces of the shoulder bone. Fixation is made to its tubercle and the capsule of the elbow joint. The fibers are completely in the lower shoulder part (on the front side) under the biceps muscle.
Elbow segment This muscle is pyramidal in shape. Its origin is the lateral epicondyle of the shoulder bone. The fibers are attached to the back of the body of the ulna and the process of the same name. Contracting, the muscle extends the forearm. It also coordinates the retraction of the capsule in the elbow joint.
triceps fibers They form longus muscle. It consists of 3 heads: medial, lateral and long. The beginning of the latter is the subarticular scapular tubercle. The lateral head departs from the posterolateral part of the shoulder bone, the medial - from rear surface. The elements are connected into a spindle-shaped abdomen. It subsequently passes into the tendon. The abdomen is attached to the joint capsule and the elbow process. With the contraction of the fibers, the forearm is unbent, the arm is retracted and the shoulder is brought to the body. The muscle is located from the olecranon to the scapula.
Forearm fibers They form two muscle groups: anterior and posterior. Each of them contains fibers of a deep and superficial layer. The latter in the anterior group includes the flexors of the hand (ulnar and radial) and fingers, the brachioradial segment, and the round pronator. The department also includes long palmar muscles. In the deep layer there is a square pronator, flexors: long thumb and deep digital. The superficial muscles of the posterior group include the ulnar, short and long radial extensors of the wrists, fingers and little fingers. In the deep layer of the department there is an arch support, muscles that abduct and extend the thumb (short and long), an extensor for the index finger.
Musculature of the hand Muscles are located on palmar surface. The fibers are divided into several groups: middle, medial, lateral. On the back of the surface of the hand are the interosseous muscles of the same name. In the lateral group there are fibers that correct the movements of the thumb: opposing, adducting, flexor and abducting. The medial section includes the short palmar muscle and the muscles of the little finger. The latter includes a short flexor, adductor and efferent fibers. In the middle group, there are worm-like, palmar and dorsal interosseous elements.
Majority muscles of the upper limb long, thin in shape, with a parallel arrangement of muscle bundles; their connective tissue framework is weakly expressed; they are usually attached far from the axis of rotation, and therefore they cannot show great strength, providing fast movements on a large scale.
On the upper limb, you can find muscles with two, three and even four heads, with three or four tendons. In the distal sections, the tendons of the muscles passing near the bones are covered with a synovial membrane. located in groups, separated from each other by intermuscular fascia-septa.
Muscles of the girdle of the upper limb for the most part, they are attached to the scapula and collarbone or start from them. Some of these muscles are located in the back, others in the chest, their course is also not the same, which determines their function.
Since the movements of the girdle of the upper limb occur in the sternoclavicular joint, in order to divide the muscles into functional groups involved in these movements, one should be guided by the location of the axes of rotation in it, the location of the muscles and the direction of the muscle bundles in relation to the axes of rotation. Thus, the muscles that cross the vertical axis of the sternoclavicular joint and are located in front of it (the pectoralis major and minor, the serratus anterior) move the belt of the upper limb forward; located behind this axis (trapezius, rhomboid, latissimus dorsi) - back, and the latissimus dorsi, like the pectoralis major, affects the belt of the upper limb through the humerus.
The muscles that raise the belt of the upper limb go from the bones of the skull and cervical vertebrae to the scapula and collarbone (upper bundles of the trapezius muscles, rhomboid muscles; sternocleidomastoid muscle; muscle that lifts the scapula, partially covered by the trapezius and sternocleidomastoid muscles ).
The muscles that lower the girdle of the upper limb go to the scapula and collarbone from below. These include: the pectoralis minor, the serratus anterior, the lower bundles of the trapezius, as well as the subclavian, located under the pectoralis major muscle, between the 1st rib and the clavicle. Lowering the girdle of the upper limb, these muscles work with the lower support. With the upper support, they will hold the body in relation to the fixed belt (in the hang on straight or bent arms, in emphasis on the uneven bars, etc.).
When classifying muscles into functional groups, according to the movements in which they participate, one should be guided by the location of the muscles or their individual parts in relation to the axes of rotation in the joints. The flexor muscles lie in front, and the extensors lie behind the transverse axis of the joint; abductor muscles - from the lateral side, and adductors - from the medial from the sagittal axis; pronators and supinators are located obliquely with respect to the vertical axis. The abstract is drawn up according to the following scheme.
Muscles of the free upper limb according to the topographic feature, i.e., according to the location, they are divided into the muscles of the shoulder, the muscles of the forearm and the muscles of the hand. On the shoulder, the anterior and posterior muscle groups are distinguished. On the front surface of the shoulder under the skin is the biceps of the shoulder (biarticular), passing through the shoulder and elbow joints; under it above and medially lies the coracobrachialis muscle, and below it lies the brachialis. The entire back surface of the shoulder is occupied by the triceps muscle of the shoulder (biarticular), with a long, medial and lateral heads.
Forearm muscles quite numerous. On its anterior surface are the flexors of the hand and fingers, as well as pronators. Superficially lie: the long palmar muscle, which occupies an almost median position, the radial and ulnar flexors of the wrist, located on the corresponding sides of this muscle, the superficial flexor of the fingers, located under all three muscles; deeply lie: deep flexor of the fingers and long flexor of the thumb, which start mainly from the medial epicondyle of the humerus. There are, as you know, two pronators. The round pronator is located in the upper part of the forearm, it goes obliquely from the medial epicondyle of the humerus to the middle of the radius; the square pronator is located in the distal forearm, it lies directly on the bones.
On the back surface of the forearm are the extensors of the hand and fingers (long and short radial extensors of the wrist, ulnar extensor of the wrist, three muscles going to the thumb - the long and short extensors of the thumb of the hand and the long abductor muscle, extensor of the index finger), as well as the muscle- supinator. The reference point for studying these muscles on anatomical preparations is the extensor muscle of the fingers, which occupies an almost median position; on the lateral side of it lie the radial extensors of the wrist with the brachioradialis muscle, on the medial side - the ulnar extensor of the wrist. The muscles leading to the thumb are best studied in their distal section. The arch support muscle is located in the upper forearm under the muscles.
On the hand, 3 muscle groups should be considered: the muscles of the elevation of the thumb, the muscles of the elevation of the small finger, and the middle group of muscles of the hand.
Trunk muscles (A) and upper limb belts(B) (front view):
A: 1 - large chest m.; 2 - front gear m.; 3 - the widest m. back; 4 - straight m. of the abdomen; 5 - external oblique m of the abdomen; 6 - transverse m. of the abdomen.
B: 1 - small chest m.; 2 - subclavian m., 3 - coraco-humeral.
Muscles of the upper limb:
A - front view: 1 - sternoclavicular mastoid m., 2 - trapezoid m., 3 - large pectoral m., 4 - anterior dentate m., 5 - latissimus m. of the back, 6 - large round m., 7 - coraco-brachial m., 8 - deltoid m., 9 - biceps m. of the shoulder, 10 - humeral m., 11 - triceps m of the shoulder, 12 - round pronator, 13 - brachioradial m., 14 - m. flexors of the hand and fingers .
B - rear view: 1 - trapezoidal m., 2 - deltoid m., 3 - subacute m., 4 - small round m., 5 - large round m., 6 - latissimus m. of the back, 7 - trihedral m. of the shoulder , 8 - shoulder m., 9 - biceps m. of the shoulder, 10 - m. extensors of the hand and fingers.
Muscles of the forearm and hand:
A - anterior group: I - pronator round, 2 - radial flexor of the wrist, 3 - long palmar m., 4 - ulnar flexor of the wrist, 5 - superficial flexor of the fingers, 6 - brachioradial m.
B - posterior group: 1 - brachioradial m., 2 - Long radial extensor of the wrist, 3 - extensor of the fingers, 4 - ulnar extensor of the wrist, 5 - long m., abducting the thumb, 6 - short extensor of the thumb, 7 - long extensor of the thumb, 8 - dorsal interosseous muscles, 9 - vermiform m., 10 - m. supinator.
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The muscles of the upper shoulder girdle include the muscles of the arms, chest, upper back and neck.
As the name implies, these muscle groups are somehow connected with the shoulder. The shoulder joint is the most complex in the human body.
I won’t give pictures of the joint and ligaments, they make me shudder. brrrr See for yourself on the net.
The upper limb is the most mobile part locomotive apparatus human body. If with an outstretched hand, as a radius, we describe a hemisphere, then we get a space in which distal the department of the upper limb, the hand, can move in any direction. The high degree of mobility of the links of the upper limb is due to well-developed muscles, which are usually divided into: muscles of the girdle of the upper limb and muscles of the free upper limb. At the same time, many muscles of the body take part in the movements of the upper limb, which either originate on its bones or are attached to them.
Muscles of the shoulder girdle and shoulder
Muscles of the girdle of the upper limb
The muscles of the girdle of the upper limb include: the deltoid muscle, supraspinatus and infraspinatus muscles, small and large round muscles, subscapularis muscle.
Starts from lower half the anterior surface of the humerus and from the intermuscular septa of the shoulder, and is attached to the tuberosity of the ulna and its coronoid process. covered in front by the biceps brachii. Function shoulder muscle consists in its participation in flexion of the forearm.
Biceps brachii has two heads, starting on the scapula from the supraarticular tubercle (long head) and from the coracoid process (short head). The muscle is attached on the forearm to the tuberosity of the radius and to fascia forearm. It is one of the bi-articular muscles. In relation to the shoulder joint, it is the flexor of the shoulder, and in relation to the elbow joint, it is the flexor and supinator of the forearm.
Since the two heads of the biceps of the shoulder, long and short, are attached to the scapula at a certain distance from each other, their functions in relation to the movement of the shoulder are not the same: the long head flexes and abducts the shoulder, the short one flexes and adducts it. In relation to the forearm, it is a powerful flexor, since it has a much greater strength than the shoulder, and, in addition, an arch support that is much stronger than the arch support of the forearm itself. The supinator function of the biceps muscle is somewhat reduced due to the fact that, with its aponeurosis, the muscle passes into fascia forearm.
The biceps muscle of the shoulder is located on its front surface directly under the skin and its own fascia; the muscle is easily palpable both in its muscular part and in the tendon, at the point of attachment to the radius. The tendon of this muscle is especially noticeable under the skin when the forearm is bent. Under the outer and inner edges of the biceps muscle of the shoulder are clearly visible medial And lateral shoulder grooves.
It is located on the back of the shoulder, has three heads and is a biarticular muscle. It is involved in the movements of both the shoulder and the forearm, causing extension and adduction in the shoulder joint and extension in the elbow joint.
The long head of the triceps muscle originates from the subarticular tubercle of the scapula, and medial And lateral heads - from the posterior surface of the humerus ( medial- below, and lateral- above the groove of the radial nerve) and from the internal and external intermuscular septa. All three heads converge together to one tendon, which, ending at the forearm, is attached to the olecranon of the ulna. This large muscle lies superficially under the skin. Compared to its antagonists, the flexors of the shoulder and forearm, it is weaker.
Between medial And lateral heads of the triceps muscle of the shoulder, on the one hand, and humerus, on the other hand, is the shoulder-muscular canal; the radial nerve and the deep artery of the shoulder pass through it.
Elbow muscle starts from lateral epicondyle of the humerus and radial collateral ligament, as well as from fascia; it is attached to the upper part of the posterior surface and partly to the olecranon of the ulna in its upper quarter. The function of the muscle is to extend the forearm.
Considering all the muscles located in the region of the shoulder joint, it is easy to see that there are no muscles inside and below it. Instead, there is a depression called the axillary cavity, which is of great topographical importance, since it contains the vessels and nerves to the upper limb.
The axillary cavity is somewhat reminiscent of a pyramid in shape, with the base turned downward and outward, and the top - upward and inward. It has three walls, of which the anterior is formed by the large and small pectoral muscles, the posterior - by the subscapularis, large round muscles and the latissimus dorsi muscle, medial- anterior serratus muscle. Muscles pass in the recess between the anterior and posterior walls: the coracobrachialis and the short head of the biceps brachii. The axillary cavity at its top has a gap located between the first rib and the clavicle (subclavian muscle). When the shoulder is abducted, the axillary fossa is clearly visible, corresponding to the location armpit. The fossa is especially well indicated if the muscles are tense. During shoulder adduction, it smoothes out.
Muscles of the upper limb (Musculi membri superioris)
The muscles of the upper limb are divided into the muscles of the girdle of the upper limb, shoulder, forearm, hand.
Muscles of the girdle of the upper limb
1. deltoid muscle ( m. deltoideus) - a large triangular muscle surrounding the shoulder joint from above, front and back
And giving roundness to the shoulder. In accordance with the places of origin in the deltoid muscle, three parts are distinguished: clavicular ( pars clavicularis), acromial (pars acromialis), spinous (pars spinalis). The clavicular part starts from the anterior surface of the lateral third of the clavicle, the acromial part - from the lateral edge of the acromion, the spinous part - from the lower surface of the spine of the scapula. The deltoid muscle is attached to the deltoid tuberosity (tuberositas deltoidea) of the humerus. The origin of the deltoid muscle is a mirror image of the attachment of the trapezius muscle, so the clavicle, acromion, and spine of the scapula are palpable between these muscles. Between the deltoid muscle and the capsule of the shoulder joint is a synovial bag (bursa subdeltoidea). Function: the main function of the deltoid muscle is shoulder abduction (by 70 °), the clavicular part flexes the shoulder, the spinous part unbends it.
2. supraspinatus muscle ( m. supraspinatus) starts from the surface of the supraspinous fossa of the scapula and from the supraspinous fascia, the tendon passes under the acromion, separated from it by a synovial bag (bursa subacromialis), then goes along the upper surface of the shoulder joint capsule, fuses with it and attaches to the upper area of the large tubercle of the humerus. Function: initiates shoulder abduction (15°) at the shoulder joint,
participates in the further abduction of the shoulder, which is produced by the deltoid muscle, stretches the capsule of the shoulder joint, preventing
her infringement, stabilizes the shoulder joint.
3. infraspinatus muscle ( m. infraspinatus) starts from the surface of the infraspinatus fossa of the scapula and from the infraspinatus fascia, the tendon of the infraspinatus muscle runs along the posterior surface of the capsule of the shoulder joint, fuses with it, and attaches to the middle area of the large tubercle of the humerus. Under the tendon of the infraspinatus muscle is a synovial bag ( bursa subtendinea musculi infraspinati). Function :
supinates the shoulder, stretches the capsule of the shoulder joint, stabilizes the shoulder joint.
4. Small round muscle (m. teres minor) starts from the posterior surface of the scapula in the immediate vicinity of its lateral edge (below tuberculum infraglenoidale ), the tendon runs along the posterior surface of the capsule of the shoulder joint, fuses with it, and attaches to the lower area of the large tubercle of the humerus. Function : supinates the shoulder, tightens the capsule of the shoulder joint, stabilizes the shoulder joint.
5. teres major muscle ( m. teres major) starts from the dorsal surface of the lower angle of the scapula, goes up and laterally, crosses the body of the humerus in front slightly below the surgical neck and attaches to the crest of the lesser tubercle of the humerus. The tendon of the teres major muscle is adjacent to the tendon of the latissimus dorsi muscle, often there is a synovial sac between them (bursa subtendinea musculi latissimi dorsi), the lower edges of the tendons of these two muscles are connected over a short distance. Between the tendon of the large round muscle and the humerus is a synovial bag (bursa subtendinea muscul teretis majoris). Function : penetrates and unbends the shoulder, brings the arm behind the back.
6. Subscapularis muscle ( m. subscapularis) starts from the surface of the subscapular fossa, its fibers are directed upward and laterally, attached to the lesser tubercle of the humerus and to the anterior surface of the capsule of the shoulder joint. Under the tendon of the subscapularis muscle is a synovial bag (bursa subtendinea musculi subscapularis). Function : penetrates the shoulder, tightens the capsule of the shoulder joint, stabilizes the shoulder joint.
mm. supraspinatus, infraspinatus, subscapularis, teres minor form around the shoulder joint"rotator cuff", which
stabilizes the head of the humerus in the articular fossa of the scapula during movements in the shoulder joint. By attaching to the capsule of the shoulder joint, these muscles stretch it and prevent it from being pinched during movement.
Shoulder muscles
According to topographic and functional principles, the shoulder muscles are divided into two groups:
1) anterior group, shoulder and forearm flexors;
2) back group, extensors of the shoulder and forearm. The anterior group includes three muscles.
1. biceps brachii ( m. biceps brachii) begins on the shoulder blade with two heads - long and short. long head ( caput longum ) originates from the supraarticular tubercle, its tendon passes through the cavity of the shoulder joint, fuses with top cartilaginous articular lip, then goes in the intertubercular groove ( sulcus intertubercularis ) of the humerus, where it is fixed by the transverse ligament of the shoulder ( lig. transversum humeri ), stretching between the large and small tubercles of the humerus. In the joint cavity and in the groove, the tendon is surrounded by a synovial sheath (vagina tendinis intertubercularis). Short head ( caput breve ) begins with a tendon from the top of the coracoid process of the scapula. In the proximal part of the shoulder, the tendon of each head passes into the muscular abdomen, both abdomens are closely adjacent to each other, but are connected together only in the distal part of the shoulder near the elbow joint. The common abdomen passes into a flat tendon, which is attached to the tuberosity of the radius ( tuberositas radii ). The aponeurosis of the biceps brachii extends medially from the tendon (aponeurosis musculi bicipitis brachii seu lacertus fibrosus , or Pirogov's aponeurosis), which merges with the fascia of the forearm. Function : supinates the forearm, while the aponeurosis pulls the ulna in the medial direction; flexes the forearm at the elbow joint, this movement is more effective when the forearm is slightly supinated. Since the biceps of the shoulder begins on the shoulder blade, it takes part in the flexion of the shoulder at the shoulder joint. The tendon of the long head is involved in the stabilization of the shoulder joint, it limits the movement of the head of the humerus upward during the contraction of the deltoid muscle.
2. Coracohumeral muscle (m. coracobrachialis) starts from the coracoid process of the scapula together with the short head of the biceps brachii muscle, part of the muscle fibers originates from the tendon short head, from the lesser tubercle of the humerus and from the medial intermuscular septum. The muscle is directed vertically downwards and is attached to the middleanterior medialsurface of the body of the humerus. Function : flexes the shoulder in the shoulder joint, is especially active when
flexion of the shoulder from an extended position.
3. The shoulder muscle ( m. brachialis) is located under the biceps muscle, starts from the distal half of the anterior surface of the body of the humerus and from the intermuscular septa (mainly from the medial), is attached to the tuberosity of the ulna (tuberositas ulnae). Function: flexes the forearm at the elbow joint.
The back group includes two muscles.
1. triceps brachii ( m. triceps brachii) consists of three heads: long, medial and lateral. long head ( caput longum ) starts from the subarticular tubercle of the scapula, its tendon fuses with the capsule of the shoulder joint; lateral head ( caput laterale ) begins with a flat tendon on the posterior surface of the body of the humerus along the upper edge of the groove of the radial nerve and from the lateral intermuscular septum; medial head ( caput mediale ) begins on the posterior surface of the body of the humerus along the lower edge of the groove of the radial nerve and from the medial intermuscular septum; the medial head is partially overlapped by the lateral and long heads. All three heads pass into a common tendon, which is attached to the upper surface of the olecranon of the ulna, part of the muscle fibers medial head attached to it on its own. Function : unbends the forearm at the elbow joint; the long head can also extend and adduct the shoulder at the shoulder joint; in addition, the long head strengthens the capsule of the shoulder joint from below.
2. Elbow muscle (m. anconeus) - small muscle triangular in shape, starts from the posterior surface of the lateral epicondyle of the shoulder, its fibers go down and medially, go along the posterior surface of the annular ligament of the radius (lig. annulare radii), attach to the lateral surface of the olecranon and the posterior surface of the proximal ¼ of the body of the ulna. Function : not really
clear, the ulnar muscle helps the triceps muscle in extension of the forearm at the elbow joint and slightly abducts the ulna when pronating the forearm.
Forearm muscles
The muscles of the forearm according to topographic and functional principles are divided into anterior and posterior groups:
1) anterior group - flexors and pronators;
2) back group - extensors and arch supports.
The muscles of the anterior group are located in the anterior fascial bed of the forearm, located in two layers - superficial and deep.
muscles surface layer start from the medial epicondyle of the humerus with a common tendon, many of them have additional points of origin from the bones of the forearm, fascia and intermuscular septa of the forearm.
1. Round pronator (m. pronator teres) begins with two heads - humeral and ulnar. Shoulder head, larger
starts from the medial epicondyle of the shoulder, from the anterior radial intermuscular septum of the forearm, from the fascia of the forearm, lies more superficially; the ulnar head, smaller, starts from the medial surface of the coronoid process of the ulna, lies deeper; both heads are connected at an acute angle, then the muscle goes obliquely along the forearm and is attached to the middle of the lateral surface of the body of the radius. Function: pronates the forearm, acts together with the square pronator; is a weak flexor of the elbow joint.
2. flexor carpi radialis ( m. flexor carpi radialis) lies medial to the pronator teres, starts from the medial epicondyle of the shoulder, from the fascia of the forearm and from the adjacent intermuscular septa, approximately in the middle of the forearm, the muscle belly passes into a long tendon that passes through the radial canal of the wrist ( canalis carpi radialis ), surrounded by the synovial sheath, is attached to the base of the II and III metacarpal bones. Function : bends the brush in wrist joint; abducts the hand during joint contraction
With extensor carpi radialis.
3. Long palmar muscle ( m. palmaris longus) lies medial to the radial flexor of the hand, starts from the medial epicondyle of the shoulder,
from the fascia of the forearm and from adjacent intermuscular septa. In the proximal part of the forearm, the muscle belly passes into a thin tendon, which in the wrist area goes over the muscle retinaculum.
takes part in the flexion of the hand in the wrist joint, II-V fingers - in the metacarpophalangeal joints.
4. Elbow flexor of the hand (m. flexor carpi ulnaris) lies medial to the long palmar muscle, begins with two heads - the humeral and radial, which are connected by a tendon arch. The smaller humeral head originates from the medial epicondyle of the shoulder, the larger ulnar head from the medial surface of the ulnar
process and from the proximal 2 3 posterior edges of the body of the ulna, from
fascia of the forearm; the tendon is attached to the pisiform bone, then continues into the ligaments: lig pisohamatum and lig. pisometacarpeum.
Function: flexes the hand at the wrist joint; leads the hand while contracting with the ulnar extensor of the wrist.
5. Superficial finger flexor ( m. flexor digitorum superficialis) lies deeper than the previous muscles; begins with two heads - humeroulnar and radial. The humeral head begins
from the medial epicondyle of the shoulder, from the ulnar collateral ligament, from the medial surface of the coronoid process of the ulna and from adjacent intermuscular septa; the radial head starts from the anterior edge of the radius (in the interval between the tuberosity of the radius and the place of attachment of the round pronator); usually the muscle is divided into two layers, the muscle fibers of the surface layer pass into two tendons (for fingers III and IV), the deep layer is also divided into two tendons (for fingers II and V). In the lower third of the forearm, the muscular belly passes into four tendons that pass to the hand through the carpal tunnel, while the tendons for the middle and ring fingers lie more superficially, the tendons for the index finger and little finger are deeper. At the level of the proximal phalanges of the II-V fingers, the tendon of the superficial flexor of the fingers is divided into two bundles, which run along the sides of the tendon of the deep flexor of the fingers and are attached to the middle phalanx of the II-V fingers. Function: flexes II-V fingers at the metacarpophalangeal and proximal interphalangeal joints, flexes the hand at the wrist joint.
The muscles of the deep layer are represented by the deep flexor of the fingers, the long flexor of the thumb and the quadrate pronator.
1. Deep finger flexor ( m. flexor digitorum profundus)
starts from the medial and anterior surfaces of the ulna and the ulnar half of the interosseous membrane of the forearm, the muscular abdomen gives rise to four tendons for the II-V fingers, which pass through the carpal canal, located deeper than the tendons of the superficial flexor of the fingers. At the level of the proximal phalanx of each finger, the deep flexor tendon passes through a gap in the tendon of the superficial flexor, forming a tendon decussation ( chiasma tendinum), and is attached to the base of the distal phalanx of the II-V fingers. Function: produces flexion in all joints that it crosses in its path - distal and proximal interphalangeal, metacarpophalangeal, radiocarpal.
2. Flexor thumb longus ( m. flexor pollicis longus) starts from the anterior surface of the radius and the radial half of the interosseous membrane of the forearm, the tendon passes through the carpal canal, located laterally from the tendons of the superficial and deep flexors of the fingers, and is attached to the base of the distal phalanx of the thumb. Function : produces flexion in all joints that it crosses in its path - interphalangeal, metacarpophalangeal, carpal joints of the thumb, wrist joint.
3. Square pronator (m. pronator quadratus) - a flat, square-shaped muscle that starts from the anterior surface of the lower quarter of the ulna, goes in the transverse direction and is attached to the anterior surface of the lower quarter of the radius. Function : penetrates the forearm and with it the hand.
The muscles of the posterior group are also located in two layers - superficial and deep.
muscles surface layer with the exception of the brachioradialis muscles, they have a common origin from the lateral epicondyle of the shoulder, many of them have additional points of origin from the bones, fascia and intermuscular septa of the forearm. Some authors divide the muscles of the surface layer into radial and ulnar groups. The radial group includes the brachioradialis muscle, short and long radial extensors of the wrist, the rest of the muscles belong to the ulnar group.
1. brachialis muscle ( m. brachioradialis) starts from the lateral supracondylar crest and lateral intermuscular septum of the humerus, attaches to the styloid process of the radius. Function : flexes the forearm at the elbow and sets it in the middle position between pronation and supination.
2. extensor carpi radialis longus (m. extensor carpi radialis longus) starts from the lateral epicondyle of the humerus and the lateral intermuscular septum of the shoulder, in the middle of the forearm the muscle belly passes into the tendon, which is located in the second canal under the extensor muscle retinaculum, is attached to the dorsal surface of the second metacarpal bone. Function : unbends the brush; shrinking at the same time radial flexor wrists, abducts the hand; flexes the forearm at the elbow joint.
3. extensor carpi radialis brevis (m. extensor carpi radialis brevis) starts from the lateral epicondyle of the humerus and the lateral intermuscular septum of the shoulder, in the middle of the forearm passes into the tendon, which, together with the tendon of the long radial extensor of the hand, is located in the second canal under the extensor muscle retinaculum, attached to the dorsal surface of the third metacarpal bone. Function : unbends the hand, contracting simultaneously with the radial flexor of the wrist, abducts the hand.
4. Finger extensor ( m. extensor digitorum) starts from the lateral epicondyle of the humerus, the lateral intermuscular septum of the shoulder, from the fascia of the forearm; the muscular abdomen gives rise to four tendons that pass in the fourth canal under the extensor retinaculum, on the dorsal surface II–V fingers form triangular tendon sprains, medium bundles
which are attached to the base of the middle phalanx, the lateral ones - to the distal phalanx. On the back surface of the hand, near the metacarpophalangeal joints, intertendon joints (connexus intertendineus) are formed between the tendons in the form of oblique fibrous bundles. Function: unbends II-V fingers in the metacarpophalangeal
And interphalangeal joints, unbends the hand in the wrist joint.
5. Little finger extensor ( m. extensor digiti minimi) starts from the lateral epicondyle of the humerus and the lateral intermuscular septum of the shoulder together with the extensor of the fingers, the tendon passes in the fifth canal under the retinaculum of the extensor muscles, forms a tendon stretch on the dorsal surface of the little finger, is attached to the base of its middle and distal phalanges. Function : extends the little finger.
6. Elbow extensor of the wrist ( m. extensor carpi ulnaris)
starts with two heads: from the lateral epicondyle of the humerus (caput humerale) and from the posterior edge of the ulna (caput ulnare), from the radial collateral ligament of the elbow joint, from the fascia of the forearm, the tendon passes in the sixth canal under the extensor muscle retinaculum, is attached to the base of the V metacarpal bones. Function: unbends the brush; contracting simultaneously with the ulnar flexor of the wrist, leads the brush.
The deep layer of the posterior group consists of five muscles; all of them, for
except for the instep muscle, they start from the posterior surface of the ulna and radius bones and the interosseous membrane of the forearm.
1. Arch support (m. supinator) starts with two heads. The superficial (humeral) head originates from the lateral epicondyle of the humerus, from the annular ligament of the radius, and from the radial collateral ligament of the elbow joint; deep (ulnar) head - from the crest of the arch support on the posterolateral surface of the ulna. Muscle fibers surround the head, neck and proximal part of the body of the radius, attach to the lateral surface of the radius above the attachment of the round pronator. Function: supinates the forearm and with it the hand.
2. The long muscle that abducts the thumb of the hand ( m. abductor pollicis longus) , starts from the posterior surface of the proximal half of the radius and ulna and the adjacent interosseous membrane of the forearm. Together with the short extensor of the thumb comes out from under the radial edge of the extensor of the fingers, passes in the first canal under the retinaculum of the extensor muscles, is attached to the lateral surface of the I metacarpal bone. Function : retracts large
60. Muscles that abduct and adduct the shoulder.
Abduct shoulder: deltoid muscle, supraspinatus muscle.
Deltoid
supraspinatus muscle starts from the supraspinous fossa of the scapula and the fascia covering it, and is attached to the large tubercle of the humerus and partly to the capsule of the shoulder joint. The function of the muscle is to abduct the shoulder and stretch the articular capsule of the shoulder joint.
lead shoulder: big pectoral muscle, latissimus dorsi, subscapularis, infraspinatus.
pectoralis major muscle
Latissimus dorsi muscle
Subscapularis
infraspinatus muscle
61. Muscles supinating and penetrating the shoulder.
Turn the shoulder outward: deltoid muscle (posterior bundles), teres major muscle, infraspinatus muscle.
Deltoid starts from the clavicle (anterior part of the muscle), acromion (middle part) and spine of the scapula (back part), and is attached to the deltoid tuberosity of the humerus. If either the anterior or the posterior part alternately works, then the upper limb moves forward and backward, i.e. flexion and extension. If the whole muscle is tensed, then its anterior and posterior parts form a resultant, the direction of which coincides with the direction of the fibers of the middle part of the muscle, contributing to the abduction of the shoulder to a horizontal level.
teres major muscle starts from the lower angle of the scapula and is attached to the crest of the lesser tubercle of the humerus, often with one tendon from the latissimus dorsi muscle. When contracting, the teres major muscle acts as a rounded elevation when the pronated shoulder is adducted. The function of the muscle is to adduct, pronate and extend the humerus.
infraspinatus muscle starts from the infraspinatus fossa of the scapula. In addition, the place of origin of this muscle is the infraspinatus fascia. Attaches to the greater tubercle of the humerus. The function of the infraspinatus muscle is to adduct, supinate and extend the shoulder in the shoulder joint.
Rotate the shoulder inward: deltoid muscle (anterior bundles), pectoralis major, latissimus dorsi, teres major, subscapularis.
Deltoid
pectoralis major muscle starts from the medial half of the clavicle (clavicular part), the anterior surface of the sternum and the cartilaginous parts of the upper five or six ribs (sternocostal part), the anterior wall of the sheath of the rectus abdominis muscle (abdominal part) and is attached to the crest of the large tubercle of the humerus. It refers to the muscles that go from the trunk to the free upper limb. This muscle pulls the scapula forward and removes it from the spinal column. But this function is secondary. Basically, it is involved in the movements of the humerus. If the torso is fixed, then this muscle adducts, pronates and flexes the humerus.
Latissimus dorsi muscle starts from the spinous processes of the lower five or six thoracic vertebrae, all lumbar, upper sacral vertebrae and from the back of the iliac crest, four teeth from the four lower ribs, is attached to the crest of the small tubercle of the humerus. Bringing and penetrating the humerus, it causes the lowering of the belt of the upper limb and bringing the scapula to the spinal column; that part of the muscle that starts from the ribs can raise them and have some effect on increasing the volume of the chest during inspiration.
teres major muscle
Subscapularis located on the anterior surface of the scapula, filling the subscapular fossa, from which it begins. The muscle is attached to the small tubercle of the humerus. She produces shoulder adduction; acting in isolation, it is its pronator.
