The term chest muscles includes several muscles in the chest area, some of which are visible under the skin and some of which are not visible.
This also includes the muscles that are located between the ribs and whose task there is primarily no human movement function in space.
Anatomy & function of the chest muscles
The division of the chest muscles into outer and autochthonous muscles is not based solely on anatomical features, but also divides the muscles functionally.
External pectoral muscles
The external chest muscles include:
- M. pectoralis major (large bust muscle)
- M. pectoralis minor (small pectoral muscle)
- M. serraturs anterior (the front saw muscle, on the side of the torso)
- M. subclavius (below the collarbone)
M. pectoralis major
The largest and most noticeable of the named muscle, which immediately catches the eye when looking at a person.
Origin vs. Insertion: the origins of this muscle include the sternum, some ribs, part of the collarbone and the rectus sheath. The rectus sheath is a muscle skin of the rectus abdominis muscle, the so-called six pack. From there, the muscle rotates through 90 degrees to the middle surface of the upper arm and starts here.
Function: the functions of the muscle result from the course of the muscles. The functions of the muscle include one Adduction, one Internal rotation and a Anteversion.
Innervation: the innervation occurs through the Nn. pectorales medialis and lateralis.
M. pectoralis minor
Of the M. pectoralis minor is the next larger muscle and lies a little bit above the large pectoral muscle.
Origin vs. Insertion: this has its origin on three ribs and inserts on the coracoid process of the shoulder blade.
Function: Pulling down the shoulder blade, which brings the raised arm down.
Innervation: Nn. pectorales medialis and lateralis.
Origin vs. Insertion: sternum and collarbone
Function: the subclavius muscle is a muscle that has no function in the strict sense. It connects the collarbone with the breastbone. This is often mentioned as its primary function, but it does not involve moving the arms or the chest.
Innervation: the innervation occurs through the N. subclavius.
M. serratus anterior
Origin vs. Insertion: the M. serratus anterior has nine muscle bellies and has its origin in nine different ribs on the side of the chest wall. From there it pulls to the middle section of the shoulder blade where it inserts.
Function: in addition to the fixation of the shoulder blade on the trunk, this muscle is to a large extent involved in the high mobility of the shoulder joint and enables the arm to be raised, since the joint socket of the shoulder is directed upwards through the contraction of the muscle. In addition, the muscle is involved in the return of the raised arm.
Innervation: the innervation occurs through the N. thoracicus longus.
Are you more interested in this topic? Then read our next article below: Serratus muscle
In addition to the main function of moving the arms, the outer chest muscles also have a function for breathing. When the upper arms are fixed, this can be achieved by leaning on the thighs, on a table or by lifting the arms, the function as auxiliary breathing muscles comes into play.
This means that the ribs are raised, which expands the volume of the chest, creates suction through negative pressure and supports breathing.
Autochthonous pectoral muscles
In addition, there are the autochthonous chest muscles, which are also known as intercostal muscles. These include:
- Mm. intercostales externi, interni and intimate (located between the individual ribs)
- Mm. subcostales (located inside the chest)
- M. transversus thoracis (also located within the chest)
The autochthonous chest muscles, in addition to the diaphragm, make a major contribution to breathing. During physical exertion, some muscles can even increase what is actually passive exhalation.
Mm. intercostales externi
Origin vs. Approach: the Mm. intercostales externi run between all the ribs of one half of the body, coming from the back and up, and moving forward and down and insert into the next lower lying rib. They are the top layer of muscle lying between the ribs.
Function: the course of the ribs lifts when the ribs contract, allowing air to enter the lungs.
Innervation: intercostal nerves 1-11
Mm. intercostal interni
Origin vs. Approach: the Mm. intercostal interni form the next lower muscle layer and are also located between all ribs on one half of the body. They run from the back and below to the front and above and start at the next higher rib.
Function: take part in the breathing process by supporting expiration (exhalation).
Innervation: see Mm. intercostales externi
Mm. intercostales imtimi
Origin vs. Approach: sometimes it is possible from this muscle group the Mm. intercostales imtimi to delimit. These run in the same direction and have an analogous function.
Function: when there is a contraction, the volume of the chest is reduced, causing forced exhalation. These muscles are usually only activated when there is physical exertion.
Innervation: see Mm. intercostales externi
Origin vs. Approach: the Mm. subcostales correspond in their course to that of the Mm. intercostal interni. However, they usually skip one rib and start at the next but one rib.
Function: in their function they show no deviation from that of the Mm. intercostal interni.
Innervation: segmentally through intercostal nerves.
M. transversus thoracis
Origin vs. Approach: the M. transversus thoracis arises from some ribs and inserts on the back of the sternum. So it also runs from the back-down to the front-up.
Function: in addition to its function during exhalation, it also serves to tighten the chest wall from the inside.
Innervation: intercostal nerves 2-6
Pectoralis major muscle illustration
Pectoralis major muscle
- Pectoralis major (1a. + 1b. + 1c.)
Pectoralis major muscle
1a. Collarbone portion -
1b. Sternum-rib area -
1c. Abdominal area -
- Collarbone -
- Upper arm shaft -
- 7th rib - Costa VII
- Costal cartilage -
- 2nd rib - Costa II
- Sternum - sternum
You can find an overview of all Dr-Gumpert images at: medical illustrations
Figure chest muscles
- Pectoralis major
Pectoralis major muscle
Triceps brachii muscle
What is the best way to train the chest muscles?
The training of the chest muscles is mainly preferred in advanced fitness training and bodybuilding. In the health sector, the priorities are placed on the training of the abdominal muscles, back muscles and arm muscle training, as this has positive effects on the human stabilization apparatus.
Overtraining should be avoided and attention should be paid to the correct execution of the exercises so as not to provoke a torn muscle fiber in the chest
Listed here are some effective chest pectoralis major exercises:
- Bench press dumbbell
- Butterfly cable pull
The development of muscles, be it the chest muscles or another muscle group, can only be achieved through targeted training, since muscle development is a reaction of the body to excessive stress.
The body is informed that the existing muscles are not sufficient, which means that it reacts with an enlargement of the existing muscles in order to be better prepared for future loads.
The main movements that are caused by the chest muscles are an anterversion, adduction and internal rotation, which is why the specified directions of movement in targeted chest muscle training are carried out specifically under more severe conditions.
However, since every person has different requirements, you should also adapt the chest muscle training to your individual needs in terms of load, intensity, recovery periods and diet.
Here, recovery and nutrition play a significant role, even if this may not seem so at first. In order to achieve the fastest possible results, for example, alcohol should be completely avoided and protein-rich food should be consumed.
Read more about a healthy and balanced diet under: Muscle building and nutrition
The goals should also be set in advance, as they can be used to define the intensity and type of training, among other things.
The simplest type of training, and also the simplest in terms of load, includes exercises with your own body weight. The following are recommended:
- Push-ups of any kind (sliding, on the wall, offset, holding)
- For example, dips between two chairs or an isometric chest press.
Higher loads can be achieved by increasing the weight, i.e. by using equipment or dumbbells. A classic exercise here is the bench press. A weight is pushed away from you while lying on your back.
In addition to the horizontal variant, you can also bring the upper body into an inclined position to challenge other areas. You can also choose between a dumbbell and a barbell. The advantage of dumbbells is the greater need for stabilization, which targets several muscle groups. However, exercising with dumbbells requires a greater amount of exercise.
Furthermore, the "Butterfly" is a popular training variant. Here, while sitting with bent arms on a device, a weight is moved from the outside to the middle of the body. The so-called "flies" are a modification of the "butterflys". These are performed lying down with dumbbells.
With all training, however, the load should not be too high and should only be increased slowly, as otherwise the training has a negative effect on the joints. Regular stretching and training of the antagonistic muscle group should also be ensured.
You can find out more about this at: Chest muscle training - exercises for a defined chest
What role does stretching play in the chest muscles?
In today's age, many human activities are performed with the torso bent over. This often leads to a shortening of the chest muscles. Desk workers, but also cleaning staff and various tradespeople are particularly affected.
However, since the human musculature consists of groups, which are divided into agonist and antagonist (opponent), if one of the groups is shortened or less stressed, an imbalance occurs, which can trigger pain and cramps.
The antagonistic (mutual) group of the external chest muscles is represented by a part of the back muscles. Inadequate or inadequate stretching is therefore a common cause of back problems.
In contrast to the external chest muscles, the autochthonous chest muscles do not have to be stretched.
The principle of stretching the chest muscles is analogous to stretching other muscle groups. Here, the muscles should be lengthened under light load until there is a slight pull.
To do this, you lift your outstretched arm approximately horizontally, rather a bit higher, and rotate your upper body and hip in the opposite direction.
Another stretching exercise is characterized by overstretching the spine. To do this, lie on your stomach and then lean on your outstretched arms. This stretches both your chest and abs. This posture should be held for a few seconds to a few minutes. If possible, you can do this stretching exercise while sitting.
Still interested in stretching exercises? Read our next article below: Stretching
Chest muscle pain
Pain in the chest area is a common problem, but the causes are usually not in the muscles, but in deeper layers or organs such as the heart. In the case of muscle pain, too, it is important to differentiate between quality and quantity, as this allows conclusions to be drawn about the cause.
Persistent dull pain is often related to problems with the cervical spine. A misalignment of these causes an unnatural posture, which in the long term leads to shortening or hardening of the chest muscles.
This can be prevented by regular stretching and regular exercise. Warmth usually also provides relief.
A slightly stronger stabbing pain can indicate a pinched nerve or overstretching or a torn muscle fiber or a misalignment. This problem typically occurs in strength athletes or people who have briefly put heavy strain on their chest muscles.
It is helpful to immobilize the affected muscles. In addition, warmth can also be used to provide relief.
If the muscles are permanently stressed or in the event of regional inflammatory reactions of the muscles, the attachment tendons can also become inflamed. This leads to permanent pain in the peripheral area of the muscles.
For the treatment of this inflammation, one should seek medical treatment, as it may be necessary to intervene with medication. In general, any type of chest muscle problem can spread to other areas of the body such as the arms and create new problems here, which is why the pain should not last too long.
This topic may be helpful to you: Chest pain
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