Deltoid(m. deltoideus) (Fig. 90, 101, 104, 106, 111, 112, 113, 114) moves the shoulder outward to a horizontal plane, while the front muscle bundles pull the arm forward, and the rear ones - back. It is a thick, triangular-shaped muscle that covers the shoulder joint and parts of the shoulder muscles. Its large bunches fan-shapedly converge to the apex of the triangle, directed downward. The muscle starts from the axis of the scapula, acromion and lateral part of the clavicle, and is attached to the deltoid tuberosity of the humerus. Under the lower surface of the muscle is the subdeltoid bursa (bursa subdeltoidea).

Supraspinatus muscle(m. supraspinatus) (Fig. 102, 114) has a triangular shape and lies in the supraspinatus fossa of the scapula, located directly under the trapezius muscle. The supraspinatus muscle lifts the shoulder and retracts the capsule of the shoulder joint, preventing it from pinching. The origin of the muscle is on the surface of the supraspinatus fossa, and the attachment point is on the upper platform of the greater tubercle of the humerus and on the posterior surface of the capsule of the shoulder joint.

Infraspinatus muscle(m. infraspinatus) (Fig. 101, 102, 104, 114) turns the shoulder outward, moves the raised arm back and pulls back the capsule of the shoulder joint. This flat muscle triangular in shape, filling the entire infraspinatus fossa. Its upper part is covered by the trapezius and deltoid muscles, and the lower part by the latissimus dorsi and teres major muscles. The infraspinatus muscle starts from the wall of the infraspinatus fossa and the posterior surface of the scapula, and is attached to the middle platform of the greater tubercle of the humerus and the capsule of the shoulder joint. At the point of its attachment to the humerus there is a subtendinous bursa of the infraspinatus muscle (bursa subtendinea mm. infraspinati).

Rice. 111. 1 - muscle that lifts the scapula; 2 - deltoid muscle; 3 - small rhomboid muscle; 4 - small pectoral muscle; 5 - subscapularis muscle; 6 - rhomboid major muscle; 7 - pectoralis major muscle; 8 - serratus anterior muscle; 9 - latissimus dorsi; 10 - coracobrachialis muscle; 11 — triceps shoulder: a) long head, b) medial head; 12 - biceps brachii; 13 - brachialis muscle; 14 - pronator teres; 15 - aponeurosis of the biceps brachii muscle; 16 - brachioradialis muscle; 17 - fascia of the forearm
Rice. 112. Muscles of the shoulder and shoulder girdle front view 1 - biceps brachii muscle: a) short head, b) long head; 2 - deltoid muscle; 3 - subscapularis muscle; 4 - coracobrachialis muscle; 5 - teres major muscle; 6 - triceps brachii muscle: a) long head, b) medial head; 7 - brachialis muscle; 8 - biceps brachii tendon
Rice. 113. Muscles of the shoulder and shoulder girdle side view 1 - supraspinatus fascia; 2 - infraspinatus fascia; 3 - teres major muscle; 4 - deltoid muscle; 5 - triceps brachii muscle: a) long head, b) lateral head, c) medial head; 6 - biceps brachii; 7 - brachialis muscle; 8 - tendon of the triceps brachii muscle; 9 - brachioradialis muscle; 10 - extensor carpi radialis longus; 11 - elbow muscle; 12 - fascia of the forearm
Rice. 114. Muscles of the shoulder and shoulder girdle rear view 1 - supraspinatus fascia; 2 - supraspinatus muscle; 3 - infraspinatus fascia; 4 - infraspinatus muscle; 5 - teres minor muscle; 6 - teres major muscle; 7 - deltoid muscle; 8 - triceps brachii muscle: a) long head, b) lateral head, c) medial head; 9 - tendon of the triceps brachii muscle; 10 - brachioradialis muscle; 11 - extensor carpi radialis longus; 12 - elbow muscle; 13 - fascia of the forearm

Teres minor muscle(m. teres minor) (Fig. 101, 102, 104, 114) turns the shoulder outward, at the same time slightly moving it back, and retracts the capsule of the shoulder joint. An oblong, rounded muscle, top part which is adjacent to the infraspinatus muscle, the anterior part is covered by the deltoid muscle, and rear end- teres major muscle. The origin point is located on the posterior surface of the scapula below the infraspinatus muscle, and the attachment point is on the lower platform of the greater tuberosity of the humerus and the posterior surface of the capsule of the shoulder joint.

Teres major muscle(m. teres major) (Fig. 101, 104, 105, 112, 113, 114) turns the shoulder inward and pulls it back, bringing the arm to the body. An oblong flat muscle adjacent to the latissimus dorsi muscle and partially covered by it in the posterior section. In the outer section, the teres major muscle is covered by the deltoid muscle. The starting point is the posterior surface of the scapula at its lower angle, the attachment point is the crest of the lesser tubercle of the humerus. Near the attachment site is the subtendinous bursa of the teres major muscle (bursa subtendinea mm. teretis majoris).

Subscapularis muscle(m. subscapularis) (Fig. 105, 111, 112) rotates the shoulder inward and takes part in its adduction to the body. A flat, triangular-shaped vastus muscle that fills the entire subscapularis fossa. It begins on the surface of the subscapularis fossa and ends on the lesser tubercle of the humerus and on the anterior surface of the capsule of the shoulder joint.

At the attachment site there is a small subtendinous bursa of the subscapularis muscle (bursa subtendinea mm. subscapularis).

a - front view; b, c - rear view;

1 - supraspinatus muscle; 2 - infraspinatus muscle; 3 - teres minor muscle; 4 - teres major muscle; 5 - long head of the biceps brachii muscle; 6 - lateral head of the triceps brachii muscle; 7 - medial head of the triceps brachii muscle; 8 - radial nerve in the brachiomuscular canal; 9 - subscapularis muscle; 10 - coracobrachialis muscle; 11 - triangular hole; 12 - four-sided hole.

Teres major muscle(t. teres major) starts from the dorsal surface of the lower angle of the scapula; attaches to the crest of the lesser tubercle of the humerus.

Function: contracting, the muscle acts as a rounded elevation when adducting the pronated shoulder, pulls the shoulder back, participates in adduction, pronation and extension of the humerus, rotates inward and leads to the body.

Innervation:

Subscapularis muscle(t. subscapularis) located on the anterior surface of the scapula, filling the subscapular fossa. Starts from the costal surface of the scapula and subscapular fascia; attaches to the lesser tubercle of the humerus and articular capsule.

Function: contracting together with the previous muscles, it produces shoulder adduction; acting in isolation, it is its pronator, rotates the shoulder inward, pronates, brings the shoulder to the body and retracts the capsule.

Since this muscle is multipennate, it has significant lifting force.

Innervation: subscapular nerve, C V -C VI.

Muscles that produce movements of the shoulder girdle. Schematically, the movements of the shoulder girdle (scapula and clavicle) are divided into:

1. Movement forward and backward with abduction of the scapula from the spinal column and adduction to it.

2. Raising and lowering the scapula and clavicle.

3. Movement of the scapula around the sagittal axis with the lower angle to the medial and lateral sides.

4. Roundabout Circulation the lateral end of the clavicle and at the same time the scapula.

These movements involve six functional muscle groups.

Forward movement of the shoulder girdle produce muscles that cross the vertical axis of the sternoclavicular joint and are located in front of it. These include the chest muscles:

1) pectoralis major acting on the belt upper limb through the humerus;

2) pectoralis minor;

3) anterior dentate.

Pectoralis major muscle (t. pectoralis major)has significant thickness and width. It covers the front of the upper ribs and participates in the formation of the anterior wall of the armpit. and refers to the muscles that extend from the trunk to the free upper limb.

The muscles of the chest and shoulder that carry out the movement of the shoulder girdle.

1 - deltoid muscle; 2 - pectoralis major muscle; 3 - biceps brachii; 4 - pectoralis minor muscle; 5 - subclavian muscle; 6 - coracobrachialis muscle; 7 - brachialis muscle.

The pectoralis major muscle pulls the scapula forward and away from the spinal column. This function is a secondary one.

Basically, it is involved in the movements of the humerus. If the torso is fixed, then this muscle adducts, pronates and flexes the humerus. The lower section of the muscle can also help raise the ribs, participating in the breathing mechanism.

The external shape of the anterior surface of the upper body largely depends on the shape of the pectoralis major muscle.

At good development of this muscle and thin skin during contraction of the muscle, not only its upper and lower boundaries are clearly visible, but also the direction of its individual bundles.

Diagram of the structure of the pectoralis major muscle

One of the structural features of the pectoralis major muscle is that its lower bundles extend in relation to the middle and upper bundles not only from below, but also from behind. On the humerus, the lower bundles are attached higher than the upper ones, coming from the collarbone. Thanks to this structural feature, the upper and lower bundles, when the shoulder is abducted, are evenly stretched and somewhat untwisted, which is especially pronounced when raising the arm up.

Pectoralis minor muscle located under the pectoralis major and moves the shoulder girdle forward and down, and also participates in the rotation of the scapula with the lower angle to the medial side (towards spinal column). If the scapula is fixed, then this muscle raises the ribs and promotes expansion chest when inhaling.

Serratus anterior muscle located on the lateral surface of the chest and covered by the pectoralis major and minor muscles. This is the main muscle that moves the scapula anteriorly and laterally. The lower teeth of this muscle lower the scapula and pull its lower angle not only down, but also forward. In addition, the upper and lower teeth can produce opposite actions, rotating the scapula either with the upper or the lower angle anteriorly. The serratus anterior muscle is especially visible when the arm is raised. Covering the lateral surface of the chest, this muscle makes up the medial wall of the axillary fossa.

Backward movement of the shoulder girdle carried out by the muscles that cross the vertical axis of the sternoclavicular joint and lie behind it. This muscle group includes:

1) trapezius muscle;

2) rhomboid muscle, major and minor;

3) latissimus dorsi muscle.

Upward movement of the shoulder girdle are carried out by muscles that cross the sagittal axis of the sternoclavicular joint and lie on the lateral side of it. They go to the scapula and collarbone from top to bottom.

Raising the shoulder girdle is performed following muscles:

1) the upper bundles of the trapezius muscle, which pulls up the lateral end of the clavicle and the acromion of the scapula;

2) the levator scapulae muscle;

3) rhomboid muscles, during the decomposition of the resultant of which there is a certain component directed upward;

4) the sternocleidomastoid muscle, which, attaching one of its heads to the collarbone, pulls it, and, consequently, the scapula upward.

The muscles that move the shoulder girdle are the trapezius, rhomboid, serratus anterior, levator scapulae, and pectoralis minor.

Trapezius muscle(Fig. 34, Table II) lies on the floor with skin on the back of the neck and back. From the back, almost all of it is visible, from the foreshortening it is visible from the side, partly from the front - above the collarbones and on the sides of the neck. Together with the deltoid muscle, it forms the shape and silhouette of the upper body, the so-called “shoulders,” plastically connecting the head with the neck and shoulder girdle. Together with its counterpart, the shape of this muscle vaguely resembles a trapezoid or a hood thrown back, which is why it was previously called the hood muscle; taken separately, it looks like an elongated triangle. It starts from the occipital bone, from the spinous processes of the cervical and all thoracic vertebrae. The superior fibers extend downwards, cover the levator scapula posteriorly and laterally, wrap forward and attach to the upper edge of the outer end of the clavicle. The middle fibers cover the supraspinatus muscle of the scapula and are attached to the upper edge of the scapular spine and to the acromion. From below, the fibers rise in the form of a wedge, spread over the edge of the scapula and, partially covering the cavity muscle, are attached to the inner end of the spine of the scapula. Around the spinous processes of the VI-VII cervical vertebrae, the muscle tendon lies in the form of a triangle, which with its pair forms a diamond-shaped cavity; in the middle of it these spinous processes protrude. The muscle forms tendons at its lower end and next to the scapular spine; all this often affects the relief of the back.

Action. Pulls the scapula to the spine, and when the upper part contracts, it raises the scapula and collarbone together with the levator scapula, producing a “shrug of the shoulders” (see Fig. 3).

Rice. 34. Muscles of the shoulder girdle, back, neck and pelvis. A - right and rear view:

/ - trapezius muscle, 2 - VII cervical vertebra, 3 - acromion, 4 - vertebral edge of the scapula. 5 - deltoid muscle. 6 - angle of the scapula (covered by the latissimus dorsi muscle). 7 - edge of the serratus anterior muscle, covered by the latissimus muscle. 8 - latissimus dorsi muscle. 9 - spine. 10- posterior iliac spines. II - iliac crest. /2-sacrum. 13- average gluteal muscle. 14 - gluteus maximus muscle. 15 - incarnation fossa. 16 - large skewer 17 - tensor muscle fascia lata. 18 - external oblique abdominal muscle. 19- costal arch,

• 20 - serratus anterior muscle.
• 21 - rhomboid muscle, 22 - teres major muscle. 23 - teres minor muscle. 24 - cavity muscle. 25 - long head of the triceps muscle. 26- inner head of the triceps muscle. 27 - external head of the triceps muscle. 28- biceps. 29 - scapular spine, 30 - sternoclavicular-

mastoid muscle;

B - right shoulder blade with muscles (muscles removed: trapezius, deltoid and latissimus dorsi):

/ - spine. 2 - serratus anterior muscle. 3 - scapula angle. 4 - teres major muscle. 5 - vertebral edge of the scapula, 6 - teres minor muscle: 7 - cavitary muscle, 8 - brachial bone. 9 - acromion. 10 - collarbone. // - whole muscle. /2 spine of the scapula, 13 - rhomboid muscle. 14 - levator scapula muscle

Rice. 35 Trapezius and serratus anterior muscles (diagrams). A- pour the shoulder high up by rotating the scapula (the latissimus dorsi muscles are removed):

/ - trapezoidal m. (upper and lower parts - both tense). 2 - deltoid m. 3 - acromion. 4 - about the shoulder blades. 5 - scapula (its lower part protrudes sideways due to rotation). 6 - the serratus anterior muscle is tense. 7 - ribs, 8 - spine. 9- chest border

when exhaling;

B- diagram of the location of the serratus anterior muscle of the scapula and chest (section): J- sternum. 2 - rib. 3- serratus anterior muscle. 4 - subscapularis muscle. 5 - humerus. 6 - spatula. 7 - rhomboid muscle. 8 - spine

The lower segment of the muscle interacts with the levator scapulae when the scapula moves up and down. At gymnastic exercises on the arms (for example, on the uneven bars), the lower sections of the trapezius muscles seem to suspend the torso from the shoulder blades. This is clearly visible if you observe a model pulling herself up between two chairs (actions in which the muscle is involved together with others are described below).

Rhomboid muscle (Fig. 34, B). It lies on both sides of the spine, almost entirely covered by the trapezius. It starts from the spinous processes of the two lower cervical and four upper thoracic vertebrae, stretches obliquely outward and slightly downward (resembling a diamond in shape) and is attached to the vertebral edge of the scapula.

Action. Pulls the scapula towards the spine.

Serratus anterior muscle (Fig. 34, 35). Lies on the anterior, lateral and posterior surfaces of the ribs. Covered above and in front by the pectoralis major muscle, behind by the scapula and vastus dorsi muscle (through which the relief of the serratus anterior is visible), partially visible under the skin in the armpit and below it, alternating with the teeth of the external oblique abdominal muscle (see illustration Laocoön).

It begins with 9-10 muscle teeth from the 9 upper ribs. The teeth merge into a muscle that runs between the scapula and the ribs and is attached to the vertebral edge of the scapula.

Action. Pulls the scapula forward and performs the arm extension described in the introduction (see p. 7, Fig. 2). In this case, the working length of the arm becomes greater due to the advancement of the scapula, the distance between the spine and the acromion increases, and the distance between the acromion and the jugular cavity remains unchanged. Participates in complex movements described below.

Rice. 36. Right half of the chest (pectoralis major, latissimus dorsi and abdominal muscles removed):

I- sternocleidomastoid muscle. 2 - trapezoidal. 3 - collarbone. 4 - acromion. 5 - coracoid process of the scapula, b-pectoralis minor muscle. 7 - deltoid muscle. 8 - short head of the biceps muscle. 9-coracobrachialis muscle. 10 - subscapularis muscle. // - pectoralis major muscle (cut). 12- long head of the biceps muscle. 13 - external head of the triceps muscle, 14 - serratus anterior muscle. 15 - brachial muscle. 16 - pronator teres. /7 - biceps tendon. 18 - flexor carpi radialis, /9 - extensor carpi radialis, 20 - Pirogov's fascia, 21 - costal arch. 22 - sternum. 23 - intercostal muscles. 24 - jugular cavity

The muscle is the levator scapula (Fig. 34, 42). Lies vertically, partly covered by the trapezius muscle. It starts from the transverse processes of the four upper cervical vertebrae and attaches to the inner corner of the scapula.

Action. Pulls the scapula upward and interacts with the lower part of the trapezius muscle.

Pectoralis minor muscle (Fig. 36). Lies on the anterior surface of the chest, covered by the pectoralis major muscle.

It starts from the II-V ribs with four teeth, goes upward and attaches to the coracoid process of the scapula.

Action. Pulls the coracoid process down and forward, pressing the top of the scapula to the chest and raising its lower corner.

The five muscles described are attached to the shoulder blade from different sides and form a powerful muscular apparatus, which is likened to a spring stretched between the shoulder blade and the chest. Tensing from different sides, they elastically fix the scapula in relation to the chest, absorbing external pressure and shocks transmitted through the hand to the scapula during the work of the hand or during blows (inflicted by the working hand). The muscles also fix the scapula when the arm needs solid, stationary support, for example, when holding a weight with the hand, or when resting the torso on the arm. In addition, by interacting, they move the scapula in any direction; in this case, some muscles act passively, like clamps, while others pull the scapula (stretching the arm, shrugging the shoulders).

The movement of the shoulder girdle when raising the arm deserves special attention. As already mentioned, shoulder elevation in shoulder joint stops. as soon as the hand reaches the horizontal level. Further lifting of the arm occurs due to rotation of the scapula (see Fig. 35, 25). The shoulder is fixed in the shoulder joint, and the scapula rotates as follows. The upper section of the trapezius muscle, contracting, pulls the acromion with the outer end of the clavicle, and they rise. The lower part of the trapezius muscle also tenses and pulls down the inner end of the scapular spine - it descends. At the same time, the lower teeth of the serratus anterior muscle contract and pull the lower corner of the scapula towards themselves - it moves forward and upward. Consequently, the scapula begins to rotate on the surface of the chest so that its articular platform with a fixed shoulder rises up. At the same time, the lower corner of the scapula also rises and moves outward - it can be felt, since it protrudes from the side of the chest, covered with the muscles raised by it (see Table I).

This movement is clearly visible on the back, especially with prominent muscles: the upper section of the trapezius muscle is tense and prominent, and its lower section is also tense and prominent. The serratus anterior muscle is also tense, and its teeth visible under the skin are also prominent when viewed from the side and front, as well as its edge, covered by the latissimus dorsi muscle. If you stand behind the model, this movement on the right shoulder blade will occur counterclockwise, and on the left shoulder blade it will occur clockwise.

Of the five muscles described, only the trapezius muscle and the serratus anterior have plastic significance. The trapezius muscle lies entirely under the skin, and all its changes are clearly visible. The relief that appears in places corresponding to the transitions of muscle tissue into tendons is also noticeable: around the VII cervical vertebra, near the scapular spine, at the lower end of the muscle.

The serratus anterior muscle is not entirely visible - only 4-5 of its lower teeth lie under the skin. But, being a fixator of the scapula, the muscle acquires greater power and corresponding relief in people of physical labor and gymnasts, since all arm movements associated with great tension invariably affect the scapula and the muscles that fix it. Therefore, in people with prominent muscles, the serratus anterior muscle will be prominent with any movement of the arm associated with great tension: lifting a weight over the head, resting on the arm, striking with the hand (for example, chopping, hammering, etc.). In thin people, the muscle teeth can be visible even with normal arm movements associated with the scapula. In addition, the lower edge of the muscle is also prominent, running obliquely backward from the 9th rib to the scapula and covered by the latissimus dorsi muscle; under strong tension, it acts in the form of an oblique roller.

Muscles of the upper and lower limb are divided into groups based on regional affiliation (topography) and the function they perform. Muscles of the upper limb(Fig. No. 87, 88, 89, 90, 91, 92) are usually divided into the muscles of the shoulder girdle and the muscles of the free upper limb: shoulder, forearm and hand. Muscles of the lower limb(Fig. No. 85, 86, 93, 94, 95, 96, 97, 98, 99, 100, 101,102,103) - on the muscles of the pelvic girdle (pelvis) and the free lower limb: thighs, legs and feet. At the same time, a complete analogy cannot be drawn between the muscles of the upper and lower limbs due to the differences in the structure and functions of the girdles and free parts of the limbs. Due to the specific function, the bones of the shoulder girdle are movably connected to the skeleton of the body and have special muscles that act on the collarbone and especially on the scapula. Thanks to this, the scapula and collarbone have great freedom of movement. On the lower limb, the pelvic girdle is firmly, almost motionlessly, connected to the spine at the sacroiliac joint.

For better assimilation of a wide variety of muscles of the limbs, let's consider their graphological structure according to topography and function (see Diagram 1).

Muscles of the shoulder girdle(Fig. No. 83, 87, 88) are located around the shoulder joint and provide it with a full range of movements (with the participation of some muscles of the chest and back). All 6 muscles of this group begin on the bones of the shoulder girdle and attach to the humerus.

1) The deltoid muscle starts from the lateral third of the clavicle, acromion and spine of the scapula. Attaches to the deltoid tuberosity of the humerus. The front part of the muscle flexes the shoulder, the middle part abducts it, and the back part extends the shoulder.

2) The supraspinatus muscle starts from the same-named fossa of the scapula and is attached to the greater tubercle of the humerus. Abducts the shoulder, being a synergist of the middle bundles of the deltoid muscle.

3) The infraspinatus muscle starts from the same-named fossa of the scapula and is attached to the greater tubercle of the humerus. Rotates the shoulder outward.

4) The teres minor muscle starts from the lateral edge of the scapula and attaches to the greater tubercle of the humerus. Synergist of the infraspinatus muscle, i.e. rotates the shoulder outward.

5) The teres major muscle starts from the lateral edge and lower angle of the scapula and attaches to the crest of the lesser tubercle of the humerus. Pulls the shoulder downward and backward, while simultaneously rotating it inward.

6) The subscapularis muscle starts from the fossa of the same name and is attached to the lesser tubercle of the humerus and its crest. Synergist of the teres major muscle and latissimus muscle back: lowers the raised hand, rotates the lowered hand inward.