Fascia of the chest. Muscles and fascia of the chest (human anatomy). What is fascia

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On the surface of the chest walls, the jugular notch of the sternum, the clavicles to the right and left of it, the xiphoid process of the sternum, as well as the ribs and costal arches are determined in the form of bone landmarks. The jugular notch of the sternum corresponds to the lower edge of the second thoracic vertebra. The lower border of the body of the sternum is at the level of the IX thoracic vertebra. The angle of the sternum is projected onto the intervertebral disc between the IV and V thoracic vertebrae. On the surface of the chest walls, the contours of the pectoralis major muscle and the deltoid-pectoral groove (in men) are determined. In women, at the level of the III-VI ribs, the mammary glands are located, separated by an interval. On the lateral surface of the chest, a serrated line is visible, formed by the initial teeth of the serratus anterior muscle and the external oblique abdominal muscle. The skin of the chest is thin, and in men there is hair in the area of ​​the sternum and shoulder blades. Sweat and sebaceous glands are most numerous in the area of ​​the sternum, shoulder blades, and on the lateral surfaces of the chest. Subcutaneous tissue is moderately expressed, more in women. The tissue contains superficial veins, terminal branches of arteries (internal thoracic, intercostal, lateral thoracic), anterior and lateral branches of intercostal nerves.

The superficial fascia, which is part of the superficial fascia of the body, is poorly developed. It participates in the formation of the mammary gland capsule, extending into its depth the connective tissue septa that divide the gland into lobes. The bundles of fascia extending from the connective tissue capsule of the mammary gland to the collarbone are called the ligament supporting the mammary gland (lig. suspensorium mammae).

The pectoral fascia (fascia pectoralis), lying under the superficial one, has two leaves (plates) - superficial and deep, which form the sheath of the pectoralis major muscle.

Superficial plate of the pectoral fascia at the top it is attached to the clavicle, medially it fuses with the periosteum of the anterior surface of the sternum. This plate continues laterally into the deltoid fascia, which continues inferiorly into the axillary fascia.

Deep plate of pectoral fascia located on the posterior surface of the pectoralis major muscle, between it and the pectoralis minor muscle. It forms the sheath of the pectoralis minor muscle. At the top, within the clavipectoral triangle (between the upper edge of the pectoralis minor muscle and the collarbone), the deep plate becomes denser and acquires the name clavipectoral fascia (fascia clavipectoralis). Lateral and inferior to the pectoralis minor muscle, the deep plate of the pectoral fascia fuses with the superficial plate of this fascia. Behind the pectoralis minor and major muscles there are three triangles. Clavipectoral triangle located between the collarbone above and the upper edge of the pectoralis minor muscle below. This triangle corresponds to the location of the clavipectoral fascia. The pectoral triangle corresponds to the outline of the pectoralis minor muscle. The inframammary triangle is located between the lower edges of the pectoralis minor and pectoralis major muscles. In the area of ​​the sternum, the pectoral fascia fuses with the periosteum of the sternum and forms a dense connective tissue plate - the anterior membrane of the sternum.

Between both pectoral muscles lying in the fascial sheaths, there is submammary cellular space. Under the pectoralis minor muscle - deep submammary space. Both of them are filled with a thin layer of fatty tissue.

In addition to these fascia, there are also thoracic and intrathoracic fascia. The pectoral fascia itself (fascia thoracica) covers the outside of the external intercostal muscles, as well as the ribs, fused with their periosteum. The intrathoracic fascia (fascia endothoracica) lines the chest cavity from the inside, i.e. is adjacent from the inside to the internal intercostal muscles, the transverse chest muscle and the inner surfaces of the ribs.

In the chest area there are distinguished: weakly expressed superficial fascia, pectoral fascia, in which superficial and deep layers are distinguished, and intrathoracic fascia.

The superficial fascia surrounds the mammary gland and forms ligaments that support it.

The superficial layer of the pectoral fascia covers the pectoralis major muscle and fuses medially with the periosteum of the sternum, above it passes into the periosteum of the clavicle, laterally into the deltoid fascia, below it passes into the serratus anterior muscle, covering it.

The deep layer lies behind the pectoralis major muscle and covers the pectoralis minor, subclavian and external intercostal muscles. Laterally, the deep leaf of the pectoral fascia passes into the axillary fascia, lining the axillary fossa

The intrathoracic fascia lines the inner walls of the chest and the diaphragm.

Abdominal muscles

The abdominal muscles form the walls of the abdominal cavity, located between the chest and pelvis. The abdominal muscles together form the abdominal muscles, which play an important role in breathing, coughing, sneezing, urination, defecation, vomiting and during childbirth in women. Topographically, the abdominal muscles are divided into anterior, lateral and posterior groups.

Anterior abdominal muscle group.

The rectus abdominis muscle (m. rectus abdominis) is located on the sides of the midline of the abdomen in the tendon sheath formed by the aponeuroses of the lateral abdominal muscles. It starts from the upper edge of the pubic bone between the pubic fusion and the pubic tubercle. Attaches to the cartilages of the V-VII ribs and the xiphoid process of the sternum. Along their length, the muscle bundles are interrupted by 3-4 intermediate tendon bridges, fused with the anterior wall of the vagina in which the muscle is located.

Function: pulls the chest down and tilts the torso, with a fixed chest, raises the pelvis.

The pyramidal muscle (g. pyramidalis) is a non-permanent muscle located between the two layers of the anterior wall of the rectus abdominis vagina. Starts from the anterior surface of the pubic bone. Attached to the linea alba.

Function: strains the linea alba.

Age-old abdominal muscle group

The external oblique muscle of the abdomen (obliquus externus abdominis) is the most superficial, its fibers run obliquely from top to bottom and from outside to inside. It begins with eight teeth from the V to the XII ribs. Attached: the posterior bundles - to the crest of the iliac bone, the remaining fibers pass into the aponeurosis, which forms the anterior wall of the rectus abdominis sheath and, fused in the midline of the abdomen with the aponeurosis of the opposite side, forms the white line of the abdomen (linea alba). The lower free edge of the aponeurosis, spreading from the superior anterior iliac spine to the pubic tubercle, folds in the form of a groove and forms the inguinal ligament.

Function: with bilateral contraction, pulls the chest down, lowers the ribs, bends the torso, with unilateral contraction, rotates the torso in the opposite direction, with a fixed chest, raises the pelvis.

The internal oblique abdominal muscle (ga. obliquus intern us abdominis) lies under the external oblique abdominal muscle. It starts from the thoracolumbar fascia, the iliac crest and the outer 2/3 of the inguinal ligament. Attached to the X-XI ribs. The aponeurosis of the internal oblique muscle above the navel splits into two plates that grasp the rectus abdominis muscle in front and behind. Below the navel, both plates pass onto the anterior surface of the rectus abdominis muscle. Both plates fuse along the midline with the plates of the aponeurosis of the internal oblique abdominal muscle of the opposite side, taking part in the formation of the white line of the abdomen.

Function: with bilateral contraction, it bends the spine, lowers the ribs, with unilateral contraction, it rotates the torso in its direction, with a fixed chest, it raises the pelvis.

The transverse abdominal muscle (m. transversus abdomims) is located under the internal oblique abdominal muscle. It starts from the VI-XII ribs, the thoracolumbar fascia, from the inner lip of the iliac crest and from the outer 2/3 of the inguinal ligament. The muscle fiber bundles are arranged horizontally. Attached to the linea alba. The aponeurosis of the transverse abdominal muscle forms the posterior wall of the rectus sheath above the navel; below the navel, the aponeurosis along the semilunar line passes to the anterior wall of the vagina. Function: when contracting on both sides, it pulls the chest down, bends the spine forward, and when contracting unilaterally, it turns the torso in the same direction.

The posterior group of abdominal muscles includes the quadratus explain muscle (m. quadratus lumborum). It starts from the transverse processes of the lumbar vertebrae and the iliac crest. Attached to the XII rib.

Function: with bilateral contraction, it is a synergist of the erector spinae muscle; with unilateral contraction, it tilts the spine in the same direction and pulls down the 12th rib.

Muscles and fascia of the chest (human anatomy)

The chest muscles are divided into chest muscles related to the shoulder girdle and upper limb (pectoralis major and minor, subclavian and serratus anterior muscles), and the chest muscles (external and internal intercostal muscles) (see Fig. 40).

The pectoralis major muscle lies superficially and is triangular. It starts from the outer part of the clavicle, sternum and from the cartilage of the II - VII ribs.

The pectoralis minor muscle is located deeper than the major muscle, begins with teeth from the II - V ribs and is attached to the coracoid process of the scapula. Pulls the shoulder blade forward and slightly downward. With a fixed shoulder blade, it raises the ribs, making it easier to inhale.

The subclavian muscle is very small in size, located between the first rib and the collarbone. Pulls the collarbone down and medially.

The serratus anterior muscle occupies the lateral surface of the chest.

It begins with teeth from the nine upper ribs and is attached to the lower angle and medial edge of the scapula. Pulls the scapula anteriorly, while simultaneously turning its lower angle outward. This ensures that the arm is abducted above the horizontal level. Together with the rhomboid muscle, it presses the scapula to the body.

All of the listed muscles, when fixing the shoulder girdle and upper limb, can participate in the act of inhalation. This explains the forced posture of patients who have difficulty exhaling (for example, patients with bronchial asthma). They usually sit holding tightly to the headboard of a bed or chair. In this position, contraction of the chest muscles enhances exhalation and makes breathing easier.

The external and internal intercostal muscles fill the intercostal spaces. The first raise the ribs (inhale), the second lower them (exhale).

Fascia of the chest. The pectoral and intrathoracic fascia are distinguished. The pectoral fascia has two layers - superficial and deep. The superficial layer covers the outside of the pectoralis major and serratus anterior muscles. The deep layer is called the clavipectoral fascia; it forms fascial sheaths for the pectoralis minor and subclavian muscles. The inside of the chest is lined by the intrathoracic fascia, which extends to the diaphragm.

Rice. 43. Diaphragm (bottom view). 1 - tendon center; 2, 5, 6 - legs of the lumbar part of the diaphragm; 3 - esophageal opening; 4 - aortic opening; 7 - costal part; 8 - sternal part; 9 - opening of the inferior vena cava

The diaphragm is the main breathing muscle. When it contracts, it flattens and lowers, while the volume of the chest increases, and inhalation occurs. When the diaphragm relaxes, it rises again in the form of a dome, the lungs collapse and exhalation occurs.