The muscles of the arms include the muscles of the forearm and shoulder. The muscles of the shoulder are divided into two categories: the flexors, or anterior muscle group, and the extensors, the posterior group.
Anterior group of musculature the shoulder is formed by three main muscles:
- coracohumeral;
- two-headed;
- shoulder muscle.
Extenders in turn are represented by two muscles:
- elbow muscle;
- triceps brachialis muscle.
Shoulder flexors
Coracobrachial muscle (m.coracobrchialis)
The coracohumeral muscle belongs to the flexor group. It originates from the top of the coracoid process, and at its other end, passing into a flat tendon, is fixed on the humerus, just below the crest of the lesser tubercle. It is attached about the same place.
Main functions: The coracohumeral muscle is involved in flexion of the shoulder at the shoulder joint. It brings the shoulder to the torso, and also turns the shoulder outward during pronation. With the shoulder fixed, m.coracobrchialis pulls the scapula forward and downward.
Biceps - biceps brachii (m.biceps brachii)
As the name implies, the biceps brachii has two heads. One of these heads is long, the other is short. The long head starts from the supraarticular tubercle of the scapula. The short head begins in the same place where the coracohumeral muscle originates - at the coracoid process. Growing together at shoulder level, both heads form a spindle-shaped muscle, passing into a tendon, which is attached to the tuberosity of the radius.
Main functions: biceps is involved in flexion at the shoulder joint of the shoulder and in flexion of the forearm at the elbow. When the forearm is turned inward, the biceps brachii muscle helps to return it to its original position.
Brachial muscle (m.brachialis)
The brachialis muscle is deeper than the biceps, however, it also belongs to the anterior shoulder group. The beginning of the muscle is two-thirds of the lower surface of the humerus, limited by the deltoid tuberosity and the capsule of the elbow joint, as well as by the lateral and medial intermuscular septum of the shoulder. The brachial muscle ends at the tuberosity of the ulna. The deeper part of the tendon of the brachialis muscle is woven into the capsule of the elbow joint.
Main function: the shoulder muscle flexes the forearm at the elbow joint.
Shoulder extensors
Triceps of the shoulder (m.triceps brachii)
The triceps of the shoulder is a large, powerful muscle that divides into three heads and is located on the back of the shoulder. The long head begins on the scapula, medial and lateral on the humerus.
Main functions: triceps brachii is an extensor, it participates in extension in the elbow joint of the forearm. In addition, through the long head, the triceps also extend the shoulder and bring it to the body.
Elbow muscle (m.anconeus)
The ulnar muscle is triangular in shape and belongs to the extensor group. The beginning of m.anconeus lies on the posterior surface of the outer epicondyle of the shoulder. The ulnar muscle is attached to the posterior edge of the ulna.
Main functions: the ulnar muscle extends the arm at the elbow.
Forearm muscles
The muscles of the forearm, like the muscles of the shoulder, are represented by the extensors and flexors. Many muscle groups in the forearm are polyarticular muscles that act on joints such as the wrist, elbow, finger and hand joints. The largest muscle of the forearm is the brachioradialis, which is engaged in flexion of the limb at the elbow joint.
Laboratory lesson
"Muscles of the upper limb"
Muscles that produce movements of the upper limb girdle
Schematically, the movements of the upper limb girdle (scapula and clavicle) are divided into:
1.Forward and backward movement with abduction of the scapula from the spinal column and adduction to it.
2. Raising and lowering the scapula and clavicle.
3.Moving the scapula around the sagittal axis by the lower angle in the medial and lateral sides.
4. Circular movement with the lateral end of the clavicle and at the same time with the scapula.
Six functional muscle groups are involved in these movements.
Forward movement
The movement of the upper limb belt forward is produced by muscles that cross the vertical axis of the sternoclavicular joint and are located in front of it. These include:
1) a large chest, acting on the belt of the upper limb through the humerus;
2) small chest;
3) anterior dentate.
Backward movement
Muscles that cross the vertical axis of the sternoclavicular joint and lie behind it are exercised. This muscle group includes:
1) trapezius muscle;
2) rhomboid muscle, large and small;
3) the broadest muscle of the back.
Upward movement
The lifting of the upper limb girdle is produced by the 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;
4) muscle lifting the scapula;
5) rhomboid muscles, during the decomposition of the resultant of which there is some component directed upward;
6) the sternocleidomastoid muscle, which, attaching with one of its head to the clavicle, pulls it, and, consequently, the scapula up.
Downward movement
Lowering is facilitated by the muscles going from the bottom up, from the chest or spinal column to the bones of the girdle of the upper limb:
1) pectoralis minor;
2) the subclavian muscle;
3) the lower bundles of the trapezius muscle;
4) the lower teeth of the serratus anterior muscle.
In addition, the muscles that go from the trunk to the shoulder, namely the pectoralis major and the broadest muscle of the back, mainly with their lower parts, help lowering.
Rotation of the scapula (movement of the lower angle inward and outward)
The rotation of the scapula inward, with the lower angle to the spinal column, produces a pair of forces formed:
1) pectoralis minor
2) the lower part of the large rhomboid muscle.
The rotation of the scapula outward, with the lower angle from the spinal column to the lateral side, occurs as a result of the action of a pair of forces formed by the upper and lower parts of the trapezius muscle.
This movement is helped by:
1) the serratus anterior muscle with its lower and middle teeth;
2) a large circular muscle with a fixed free upper limb.
Circular motion
The circular movement of the upper limb belt occurs as a result of the alternate contraction of all its muscles.
Muscles that make movements in the shoulder joint
In the shoulder joint, movements are possible around three mutually perpendicular axes:
1) abduction and adduction around the anteroposterior axis;
2) flexion and extension around the transverse axis;
3) pronation and supination around the vertical axis;
4) circular motion (circumduction).
These movements are provided by six functional muscle groups.
Shoulder abduction
The muscles that abduct the shoulder cross the sagittal axis of rotation at the shoulder joint and are located laterally from it. The humerus is abducted by the muscles:
1) deltoid and
2) supraspinatus.
Shoulder adduction
There are no special muscles that would cross the sagittal axis of the shoulder joint and were located medially from it, therefore, the adduction of the shoulder according to the rule of the parallelogram of forces is carried out with simultaneous contraction of the muscles located in front (pectoralis major muscle) and behind the shoulder joint (broadest and large round). These muscles are helped by:
1) infraspinatus;
2) small round;
3) subscapularis;
4) the long head of the triceps brachii;
5) the coracohumeral muscles.
Shoulder flexion
The flexor muscles of the shoulder cross and are located in front of the frontal (transverse) axis of the shoulder joint.
Flexion of the shoulder (moving it forward) is produced by the muscles:
1) deltoid, its front part;
2) large chest;
3) coracohumeral;
4) biceps brachii.
Shoulder extension
The muscles that extend the shoulder (moving it backward), like the flexors of the shoulder, cross the frontal axis of the shoulder joint, but are located behind it. Extension of the shoulder is produced by the following muscles:
1) its deltoid posterior part;
2) the broadest muscle of the back;
3) infraspinatus;
4) small round;
5) large round;
6) the long head of the triceps brachii.
Pronation of the shoulder
Pronation of the shoulder, i.e. turn inward, produce muscles; which cross the vertical axis of the shoulder joint, attaching in front of it. These include:
1) subscapularis;
2) large chest;
3) deltoid, its front part;
4) the broadest muscle of the back;
5) large round;
6) coracohumeral.
Shoulder supination
Supination, i.e. turning the shoulder outward, produces muscles that, like the pronators, cross the vertical axis of the shoulder joint, but are located behind it:
1) the back of the deltoid muscle
2) small round muscle
3) infraspinatus muscle
4) biceps brachii
abstract
Exercises for the shoulder extensors
Introduction
push up exercise dumbbell barbell
The muscles of the shoulder girdle surround the shoulder joint, providing numerous movements in it. All of them start from the scapula and are attached in different places of the humerus. The delta muscle abducts, flexes and extends the shoulder. The supraspinatus and infraspinatus muscles abduct and rotate the shoulder. The small and large round muscles rotate and lower the shoulder. The subscapularis muscle is also involved in rotation in the shoulder joint. The muscles of the free upper limb are subdivided into sections of the arm. The shoulder muscles have an anterior flexion group and a posterior extensor group. Flexors: biceps brachii (biceps). Extensors: triceps muscle (triceps).
Triceps(triceps; lat.musculus triceps brachii) - the triceps muscle of the shoulder, extends the elbow, is located on the back of the humerus, consists of three bundles or heads - long (caput longum), lateral (caput laterale) and medial (caput mediale).
Many athletes, especially beginners, neglect triceps training, as they believe that the biceps play the main role in the appearance of the arms. This is not true, since when looking at a person (both from the front and from the back), it is the triceps, not the biceps, that determines the thickness of the shoulder.
As mentioned above, the triceps consists of three heads, which form the so-called triceps horseshoe. The bodybuilding literature and articles often describe exercises that target one of the triceps heads so that only that head can be selectively trained. In fact, almost all triceps exercises involve all three of its heads, and the mass fraction of a particular head is determined by the athlete's genetic data.
Triceps requires a lot of concentration, so avoid cheating when doing exercises. For good results, the most accurate technique is required.
There are a large number of triceps exercises, but not all of them are equally effective. Here is a list of the best exercises that will give you the best results in increasing your triceps.
1. Bench press
The bench press is a basic free-weight bodybuilding and powerlifting exercise designed to develop the muscles of the chest and arms (triceps) and the anterior deltoid muscle.
Starting position... Lying face up on a special bench for the press, legs bent at the knees and shoulder-width apart, feet firmly pressed to the floor. The back of the head, shoulder blades and pelvis are firmly pressed against the bench. The bar is held on arms straightened in front of you, the grip is wide, from above. The grip width must be selected in such a way that when the projectile is lowered to the chest, the forearms are parallel to each other. It is necessary to lie down on the bench in such a way that the bar of the bar, while on the racks, is in front of your eyes.
Execution technique.Smoothly lower the barbell down until it touches the middle of the chest, then, without stopping and hitting, squeeze up until the arms are fully extended. To increase the load on the muscles of the chest, the elbows should be pulled apart at all times when performing the bench press.
Trauma safety technique... It is not recommended to tear the pelvis off the bench - it is traumatic for the lumbar spine. When performing the exercise, do not take your feet off the floor or put them on a bench - loss of balance and injury to the shoulder joint is possible. When the back of the head is detached from the bench during the bench press, the trajectory of the projectile is distorted and the traumatic load on the cervical spine increases. The projectile must be lowered to the middle of the chest; when the projectile is lowered to the neck or to the lower part of the chest, a traumatic load is created on the shoulder joint. This exercise is recommended to be performed with a safety net, if the athlete cannot raise the barbell, then it will press him to the bench and it will be very difficult to get rid of it on his own.
Trained muscle groups.
2. Bench press dumbbells
This exercise is one of the options for the bench press. The difference lies in the used inventory. The use of dumbbells provides an isolated load on each arm and places higher demands on intermuscular coordination.
Starting position.Lying face up on a bench, legs bent at the knees and shoulder-width apart, feet firmly pressed to the floor. The back of the head, shoulder blades and pelvis are firmly pressed against the bench. Dumbbells are held on arms straightened in front of you, palms of the hands are turned to the legs.
Execution technique.The dumbbells are lowered down to the level of the chest, while the arms are spread apart so that the forearms are parallel to each other, after which the dumbbells are lifted upwards with simultaneous reduction of the hands, the position of the hands does not change during the exercise. When performing the exercise, the forearms should be parallel to each other at all times.
Trauma safety technique. When performing the exercise, it is not recommended to lower the dumbbells below chest level and deviate the forearms from the vertical to the floor - this is traumatic for the shoulder joint. It is forbidden to lift dumbbells from the floor or to put them on the floor while lying on a bench - this is traumatic for the shoulder joints, it is desirable that the dumbbells be handed over and taken away by the partners. It is not recommended to tear the pelvis off the bench - it is traumatic for the lumbar spine. When performing the exercise, do not take your feet off the floor or put them on a bench - loss of balance and injury to the shoulder joint is possible. When the back of the head is detached from the bench during the bench press, the trajectory of the projectile is distorted and the traumatic load on the cervical spine increases. The projectile must be lowered to the middle of the chest; when the projectile is lowered to the neck or to the lower part of the chest, a traumatic load is created on the shoulder joint.
Trained muscle groups.The pectoralis major muscle, the triceps muscle of the shoulder, the anterior and lateral bundle of the deltoid muscle, the coracohumeral muscle.
3. Push-ups
Push ups- a basic, multi-joint exercise performed on the floor. The main muscles involved are the pecs and triceps.
Starting position.The emphasis is lying, the legs are together, the back is bent, the legs are straightened and together with the body form one line, the arms are straightened at the elbows and spaced slightly wider than shoulder level, we look straight ahead.
Technique execution.Maintaining a straight body position, due to flexion in the elbow and shoulder joints, go down to the parallel of the shoulders to the floor, and then return to the starting position. Keep your torso and legs straight during the exercise.
Technique injury safety... In this case, the so-called deep push-ups should be avoided, when the hands are placed on supports and the athlete lowers the body below the level of the hands, this exercise is traumatic for the shoulder joints.
Trained muscular group... The pectoralis major muscle, the triceps muscle of the shoulder, the anterior and lateral bundle of the deltoid muscle, the coracohumeral muscle.
4. Press the bar from the shoulders ("Army press")
Army press- one of the best exercises for developing the muscles of the shoulder girdle: deltas, upper chest, and triceps.
The original position... Standing (or sitting), legs shoulder-width apart, back bent, shoulders unfolded, the bar rests on the shoulders in front, the grip on top is slightly wider than shoulder level, the elbows are raised slightly up and turned outward.
Technique fulfillment... Without deviating the body back, squeeze the bar up behind the head until the arms are fully extended at the elbow joints, and then lower it back onto the shoulders. It is necessary to look forward, do not raise your head up.
Technique injury safety... It is not recommended to tilt the torso back during the exercise - it is traumatic for the lumbar spine and lowering the barbell below shoulder level - traumatic for the shoulder joints. When performing the exercise, it is not recommended to raise your head up (often done by beginners), in this case, the body deviates back and creates a traumatic load on the lumbar spine.
Trained muscular group... The anterior bundle of the deltoid muscle, the trapezius muscle, the triceps muscle of the shoulder, the upper part of the pectoralis major muscle.
5. Press the bar from behind the head with a wide grip
The original position... Standing (or sitting), feet shoulder-width apart, back bent, shoulders unfolded. The bar lies on the shoulders behind the head, the grip is from above, wide.
Technique fulfillment... Without deviating the torso back and not bending the legs at the knees, squeeze the bar up until the arms are fully extended at the elbow joints, and then lower it back.
Technique injury safety... It is not recommended to lower the barbell below shoulder level - it is traumatic for the shoulder joints, it is not recommended to tilt the body back during the lifting of the projectile - it is traumatic for the lumbar spine. When performing the exercise, it is not recommended to raise your head up (often done by beginners), in this case, the body deviates back and creates a traumatic load on the lumbar spine.
Trained muscular group... Anterior and lateral bundle of the deltoid muscle, trapezius muscle, triceps muscle of the shoulder.
6. French press
French press- exercise in bodybuilding and powerlifting for the development of triceps.
The original position... Standing, feet shoulder-width apart, the bar is on the arms outstretched upward, the grip is from above, the grip is narrow.
Technique fulfillment... Keeping your shoulders perpendicular to the floor and not spreading your elbows to the sides, lower the barbell down behind your head to the level of parallel to the forearms to the floor, and then return to its original position. During the exercise, do not spread your elbows to the sides and do not lower your shoulders forward.
Technique injury safety... It is not recommended to use limit and near-limit training weights in this exercise, since this can lead to damage to the tendons in the area of ββthe elbow joint, it is recommended to use such a weight with which the athlete can perform at least 12-15 lifts.
Trained muscular group... Triceps muscle of the shoulder.
7. Bench Press
Bench press Tate is one of the varieties so-called "triceps presses" , by the nature of the work, it is similar to the French bench press, but unlike it, it does not load the elbow joints so much.
The original position... Lying on a bench, face up, legs bent at the knees and spaced shoulder-width apart, feet firmly pressed to the floor. The pelvis, shoulder blades and the back of the head are firmly pressed against the bench. The dumbbells are held by the hands at the chest in an upright position, the palms of the hands are turned towards the pelvis.
Technique fulfillment... By extending the arms at the elbow joints, raise the dumbbells up until the arms are fully extended, while the dumbbells must be kept as close to each other as possible throughout the exercise.
Technique injury safety... It is not recommended to perform this exercise with extreme and near-limiting weights, this can lead to the development of inflammatory processes in the tendons in the region of the elbow joint, it is necessary to use such a weight with which the athlete can perform at least 12-15 lifts.
Trained muscular group... Triceps.
8. Dips on the uneven bars
Dips on the uneven bars- a basic exercise in bodybuilding and powerlifting performed on the uneven bars, which develops the pectoral muscles and triceps.
The original position.The emphasis is on parallel bars, arms are straightened, legs are bent at the knees and connected together, grip with palms inward.
Technique fulfillment... By abducting the shoulders back and bending the arms at the elbow joints, lower the body down to the parallel of the shoulders to the floor, and then return to its original position. When performing the exercise, it is necessary to avoid swinging the body, as this significantly reduces the effectiveness of the exercise.
Technique injury safety... It is not recommended to fall below the level of parallel to the shoulders to the floor and to use limit and near-limit weights - it is traumatic for the shoulder joints, it is recommended to use such a weight with which the athlete is able to do at least 8-10 approaches.
Trained muscular group.The pectoralis major muscle, the anterior bundle of the deltoid muscle, the triceps muscle of the shoulder.
9. Extension of arms on the upper block (press on the upper block)
Extension of the arms on the upper block is a local exercise for the development of the triceps, in the structure of movement it is similar to the French press, but does not load the elbow joints so much. The exercise is local (if performed correctly) and is performed on the upper block simulator.
The original position.Standing facing the simulator, legs are shoulder-width apart (one of the legs can be put forward a little for stability), the body is slightly tilted forward, the handle of the simulator is pulled up to the chest, the grip is narrow from above, the elbows are tightly pressed to the body.
Technique fulfillment... Without straightening the torso and not spreading the elbows to the sides, lower the handle of the simulator down until the arms are completely straightened at the elbow joints, and then return to the starting position. When performing the exercise, it is necessary to avoid spreading the elbows to the sides, since in this case the main part of the load is shifted from the triceps to the deltoid muscle.
Technique injury safety... It is not recommended to use limit and near-limit weights - it is traumatic for the elbow joints, it is recommended to set such a weight with which the athlete is able to make at least 12-15 lifts.
Trained muscular group... Triceps muscle of the shoulder.
10. Extension of the arm in the slope
The bent over extension is a local exercise for the development of the triceps. Due to the specifics of the movement, the elbow joint experiences a significantly lower load than when performing the French bench press, which is a significant advantage of this exercise.
The original position... Standing in an inclination, the shoulder of the working hand is pressed to the body, the forearm is lowered down, the hand with the dumbbells is turned with the palm inward. The leg of the same name from the working arm is bent at the knee and put forward, the forearm of the free hand rests on the thigh of this leg and performs the function of support, the leg of the same name from the working hand is set back to the side and stands on the entire foot. The head is raised up.
Technique fulfillment... Maintaining the original position of the body and not taking the shoulder of the working arm to the side, raise the dumbbell back and up due to the full extension of the arm at the elbow joint, and then smoothly lower the forearm to its original position. At the top point, you can slightly raise the shoulder of the working hand up to increase the load. The exercise must be performed without jerking or swinging.
Technique injury safety... It is not recommended to use limiting and near-limiting weights - this is traumatic for the elbow joints, it is recommended to set such a weight with which it is possible to make at least 12-15 lifts.
Trained muscular group... Triceps brachii, posterior bundle of the deltoid muscle.
Conclusion
Do not train your triceps more than once a week. Keep in mind that many pectoral exercises stress the triceps, so design your training program so that the triceps and pectorals are trained on separate and distant days. To increase efficiency, do triceps workouts of different intensities: light - medium - hard, and so on. Rest for at least 1 week after a hard workout.
In classic splits, the triceps are usually the most overloaded muscle, due to the very specifics of training in split programs. To increase the volume of the triceps muscle, do 8-15 repetitions. The total number of triceps sets (the sum of the sets of all triceps exercises) is 1-3.
It is a mistake to think that isolation is the best choice for arm muscles. Triceps, like other muscles, are best swayed by basic exercises, in particular the close-grip bench press and push-ups on the uneven bars. For athletes with less than 2 years of experience, it is best not to use isolation exercises.
List of sources used
1.Homotomy. [Electronic resource]. - Access mode: URL - http://www.homotomia.ru/smert/155-myshczy.html [date of access 04/03/2013];
2.SportWiki - encyclopedia of scientific bodybuilding. [Electronic resource]. - Access mode: URL - http://sportswiki.ru/ [date of access 03.04.2013];
URAL STATE UNIVERSITY OF PHYSICAL CULTURE. Exercises for the muscles of the chest, shoulders and upper back [Electronic resource]. - Access mode: URL - http://atletikgymnastik.narod.ru/index21.htm [date of access 04/03/2013].
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There are no special muscles that would cross the sagittal axis of the shoulder joint and were located medially from it, therefore, the adduction of the shoulder according to the rule of the parallelogram of forces is carried out with simultaneous contraction of the muscles located in front (pectoralis major muscle) and behind the shoulder joint (broadest and large round). These muscles are helped by:
1) infraspinatus;
2) small round;
3) subscapularis;
4) the long head of the triceps brachii (see p. 160);
5) the coracohumeral muscle (see page 156).
Abdominal muscle(see Fig. 38) is located in the infraspinatus fossa of the lobe, from which it and begins. In addition, the infraspinatus fascia is the origin of this muscle. Muscle is attached to the large tubercle of the humerus, being covered partly by the trapezium and partly by the deltoid muscle.
The function of the infraspinatus muscle is adduction, supination and extension of the shoulder in the shoulder joint. Since this muscle is attached to the capsule of the shoulder joint, then during supination of the shoulder, it simultaneously pulls the capsule off, protecting it from infringement.
Small round muscle(see Fig. 38) is located below the infraspinatus muscle. She begins from the scapula, and is attached to the large tubercle of the humerus and promotes adduction, supination and extension of this bone.
Large round muscle(see fig. 38) begins 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 large round muscle acts in the form of a rounded elevation when the pronated shoulder is brought. The function of the muscle is adduction, pronation and extension of the humerus. Subscapularis muscle is located on the anterior surface of the scapula, filling the subscapular fossa, from which and begins. Attached muscle to the small tubercle of the humerus. Contracting together with the previous muscles, it produces the adduction of the shoulder; acting in isolation is his pronator. Since this muscle is multi-feathery, it has significant
60. Muscles abducting and abducting the shoulder.
Take your shoulder: deltoid muscle, supraspinatus muscle.
Deltoid
Supraspinatus muscle starts from the supraspinatus 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: pectoralis major, latissimus dorsi, subscapularis muscle, infraspinatus muscle.
Pectoralis major muscle
Latissimus dorsi
Subscapularis muscle
Infraspinatus muscle
61. Muscles supinating and penetrating the shoulder.
Turn the shoulder outward: deltoid muscle (posterior bundles), large round muscle, infraspinatus muscle.
Deltoid starts from the clavicle (anterior part of the muscle), acromion (middle part) and spine of the scapula (posterior part), and attaches to the deltoid tuberosity of the humerus. If the front, then the rear part of it works alternately, then the upper limb moves forward and backward, i.e. flexion and extension. If the muscle is strained as a whole, then its front and back 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.
Large round 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. When contracting, the large round muscle acts in the form of a rounded elevation when the pronated shoulder is brought. The function of the muscle is adduction, pronation and extension of the humerus.
Infraspinatus muscle starts from the infraspinatus fossa of the scapula. In addition, the infraspinatus fascia is the origin of this muscle. Attaches to the large tubercle of the humerus. The function of the infraspinatus muscle is adduction, supination and extension of the shoulder in the shoulder joint.
Turn their shoulder inward: deltoid muscle (anterior bundles), pectoralis major muscle, latissimus dorsi muscle, large round muscle, subscapularis muscle.
Deltoid
Pectoralis major muscle starts from the medial half of the clavicle (clavicular part), the anterior surface of the sternum and 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 attaches to the crest of the greater 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 away from the spinal column. But this function is secondary. Basically, it is involved in the movements of the humerus. If the trunk is fixed, then this muscle leads, penetrates and flexes the humerus.
Latissimus dorsi starts from the spinous processes of the lower five to six thoracic vertebrae, all lumbar, upper sacral vertebrae and from the back of the iliac crest, with four teeth from the four lower ribs, attaches to the crest of the lesser tubercle of the humerus. Leading and pronating the humerus, it causes the lowering of the girdle of the upper limb and the adduction of the scapula to the spinal column; that part of the muscle that starts from the ribs can lift them and have some effect on the increase in the volume of the chest during inhalation.
Large round muscle
Subscapularis muscle is located on the front surface of the scapula, filling the subscapular fossa, from which it begins. The muscle is attached to the small tubercle of the humerus. It produces shoulder adduction; acting in isolation is his pronator.