Muscles and fascia of the back
Back - covers the entire back surface of the body. Its upper border is made up of the external occipital protrusion and the superior nuchal line. The sacroiliac joints and coccyx serve as the lower border. On the sides, the back is bordered by the shoulder girdle, axillary fossa and the lateral surfaces of the chest and abdomen along the posterior axillary lines.
By location, there are superficial and deep muscles back.
Superficial muscles develop in connection with the upper limb. These include: the trapezius muscle, the broadest muscle of the back, the muscle that lifts the scapula, the large and small rhomboid muscles. The superior and inferior serratus posterior muscles are located deeper and attach to the ribs.
Deep muscles, which make up most of the musculature of the back, are derivatives of myotomes - muscle rudiments of the primary body segments - somites. The deep muscles include the belt muscles of the head and neck, the erector spinal column, the transverse spinous muscle (including short muscles atlantooccipital joint - suboccipital muscles), interspinous and intertransverse muscles.
By origin: the back muscles are divided into 3 groups:
- Muscles of ventral origin. These include the superficial muscles, with the exception of the trapezius muscle, while the large and small rhomboid muscles, the muscle lifting the scapula are truncofugal, and the latissimus dorsi muscle is truncopetal.
- The muscles derived from the fifth branchial arch are the trapezius muscle.
- Muscles of dorsal origin (autochthonous). These include the deep back muscles.
On the back, two fascia are distinguished: superficial and deep.
The superficial fascia covers the outer surface of the trapezius and latissimus dorsi.
The deep fascia is called the thoracolumbar fascia (fascia thoracolumbalis) and covers the deep muscles of the back. The fascia reaches its greatest development in the lumbar region, where two sheets are distinguished in it: superficial and deep. The superficial leaf grows medially with the spinous processes of the lumbar vertebrae, the supraspinous ligaments and the median sacral ridge. The deep leaf starts from the transverse processes of the lumbar vertebrae and is located between the XII rib and the iliac crest. At the lateral edge of the muscle that straightens the spinal column, the superficial and deep sheets of the fascia are combined into one. A deep plate of the thoracic lumbar fascia separates the erector muscle from the quadratus lumbar muscle. Within the chest wall, the fascia is represented by a thin plate that separates the erector muscle from the more superficial muscles. Medially, this fascia is attached to the spinous processes of the thoracic vertebrae, laterally - to the corners of the ribs. In the back (nuchal) region of the neck, between the muscles located here, there is a nuchal fascia (fascia nuchae).
Thus, deep muscles are embedded in a closed osteo-fibrous vagina, and the initial part of the musculus erector spinae is in n.
Muscles and fascia of the chest
The muscles of the chest are located in several layers, which is due to their unequal origins and different functions.
More superficial are those muscles that develop in connection with the laying of the upper limb. They connect the latter to the chest. These include the pectoralis major and minor, subclavian and serratus anterior muscles.
The deep layers of the musculature of the chest are represented by their own, autochthonous muscles that develop from the ventral sections of the myotomes. These muscles begin and attach within the chest wall. These include the external and internal intercostal muscles, hypochondria, and the transverse chest muscle. In this case, the external intercostal muscles are observed along the length from the tubercles of the ribs (near the transverse processes of the vertebrae) to the line of transition of the ribs into the cartilage. Throughout the cartilaginous part of the ribs, they are replaced by a dense membrane (membrana intercostalis externa). Internal intercostal muscles occupy the intercostal spaces from the edge of the sternum to the costal angle. For the rest of the length (from the costal angle to the spinal column), the internal intercostal muscles are replaced by an internal intercostal membrane (membrana intercostalis interna).
The superficial fascia in the chest area is poorly developed. It divides into two sheets at the level of the third intercostal space, forming a capsule for the mammary gland. At the top, the fascia is fused to the clavicle. From the anterior surface of the fascia to the skin and the nipple of the mammary gland, dense bundles continue - the ligaments that support the mammary gland (ligamenta suspensoria mammaria). The outer surface of the fascial sheath of the mammary gland is connected to the subcutaneous tissue and through it to the skin. The capsule gives off spurs extending deep between the lobules of the gland.
The pectoral fascia (fascia pectoralis) consists of superficial and deep sheets. The superficial layer covers the pectoralis major muscle and passes medially into the periosteum of the sternum, at the top - into the periosteum of the clavicle, laterally - into the deltoid fascia. A deep leaf lies under the pectoralis major muscle and surrounds the subclavian and pectoralis minor. Continuing upward, this leaf becomes denser within the clavicothoracic triangle and is called the clavicular-pectoral fascia (fascia clavipectoralis). The superficial and deep layers of the thoracic fascia are interconnected at the lower edge of the large pectoral muscle and pass into the axillary fascia (fascia axillaris).
In addition to these fascia, the thoracic and intrathoracic fascia are also distinguished. The pectoral fascia itself (fascia thoracica) covers the outside of the intercostal muscles, as well as the ribs. The intrathoracic fascia (fascia endothoracica) lines the chest cavity from the inside, that is, it is adjacent to the internal intercostal muscles, the transverse muscle of the chest and the inner surfaces of the ribs.
Cellular spaces of the chest wall
Between the superficial muscles of the chest there are superficial and deep subpectoral cellular tissue spaces. The superficial subpectoral space is located between the posterior surface of the pectoralis major muscle and the anterior surface of the pectoralis minor. The deep subpectoral space is limited by the posterior surface of the pectoralis minor and a sheet of its own fascia, which covers the outside of the ribs and external intercostal muscles. Both spaces are filled with connective tissue and adipose tissue, which passes into the tissue of the axillary cavity.
Within each intercostal space, two muscle-fascial clefts and one cellular space can be distinguished.
The superficial fascial-muscular gap is not continuous throughout the entire intercostal space, since its own fascia is fused with tendon inclusions in the external intercostal muscles. The superficial fascial-muscular cleft extends beyond the corresponding intercostal space to the outer surface of the overlying rib. With ax, the ribs spreads to the outer surface of the overlying, intact rib.
The deep fascial-muscular gap is also not continuous, since numerous bridges extend from the internal intercostal fascia into the thickness of the internal intercostal muscles. This gap also extends to the inner surface of the adjacent ribs, and the intercostal space, localized in the deep fascial-muscular gap,
is not limited to the limits of one intercostal space, but extends to the inner surface of the ribs located above and below the damaged rib.The intermuscular fiber space of the intercostal space is located between the internal and external intercostal muscles with their fascial cases. The intermuscular cellular space of the intercostal space has a triangular shape. From the corners of the ribs to the mid-axillary line, it is bounded by the intercostal muscles and the groove of the rib. Here, in the loose tissue, the intercostal neurovascular bundle is located. Moreover, the upper position in it is occupied by the intercostal artery, below it is the vein of the same name, and downward from the vessels is the intercostal nerve.
The position of the neurovascular bundle throughout the intercostal space is not the same. From the paravertebral to the scapular line, the neurovascular bundle runs approximately in the middle of the intercostal space between the inner intercostal membrane and the external intercostal muscles. Since fascial fibers are woven into the wall of the intercostal artery, the artery does not collapse when damaged, its lumen gapes, which explains the strong, sometimes gushing bleeding. From the scapular to the mid-axillary line, the neurovascular bundle lies between the external and internal intercostal muscles in the sulcus costalis, hiding behind the lower edge of the rib. Such topographic and anatomical features contribute to injuries of the neurovascular bundle with ah ribs. The location of the bundle along the lower edge of the rib forces, when puncturing the chest cavity, to draw the needle along the upper edge of the rib. Anterior to the middle axillary line, the intercostal neurovascular bundle leaves the sulcus costalis and goes into the intercostal space near the lower edge of the rib. At this level, the branching of the intercostal vessels and the nerve often occurs.
Muscles and fascia of the abdomen
The abdomen is the part of the body located between the ribcage and the pelvis. The upper border of the abdomen runs from the xiphoid process along the costal arches to the XII thoracic vertebra. On the lateral side, the border of the abdomen runs along the posterior axillary line from the costal arch above to the iliac crest below. The lower border of the abdomen on the right and left is formed by the anterior segment of the iliac crest and a line conditionally drawn at the level of the inguinal folds from the superior anterior iliac spine to the pubic tubercle.
In order to more accurately determine the location of the organs in the abdominal cavity, their topography and projection onto the external integument, the abdomen is divided by two horizontal lines into 3 floors. One passes between the cartilages of the X ribs - the intercostal line, the other - between the superior anterior iliac spines - the interspinous line. Thus, the upper floor is distinguished - the upper womb, the middle floor - the womb, and the lower floor - the lower womb. In addition, two vertical lines drawn along the lateral edges of the rectus abdominis muscles from the costal arch to the pubic tubercle, each of the floors is subdivided into 3 separate areas. Accordingly, in the epigastrium, the right and left hypochondria and the epigastric region are distinguished, in the mesogastrium - the right and left lateral regions and the umbilical region, in the hypogastrium - the right and left inguinal regions and the pubic region.
The abdominal muscles form the muscular basis of the lateral, anterior and posterior walls of the abdominal cavity. According to the topography and the place of origin and attachment, the muscles can be divided into lateral, anterior and posterior.
The lateral walls of the abdominal cavity include 3 broad muscles: the external oblique muscle of the abdomen, the internal oblique muscle of the abdomen, the transverse abdominal muscle. Arranged in layers, the muscle bundles pass in different directions. In the external and internal oblique muscles of the abdomen, the muscle bundles intersect each other at an angle of about 90º, and the bundles of the transverse abdominal muscles are oriented horizontally.
The anterior sections of these muscles pass into wide tendon stretches - aponeuroses, which, covering the rectus abdominis muscle in front and behind, form an aponeurotic vagina for it. Further, having reached the anterior midline, the fibers of the aponeuroses of the broad muscles of the abdomen on the right and left sides intersect and form a longitudinal cord, called the white line of the abdomen.This feature of the topography of the muscles and their aponeuroses, which form the lateral walls of the abdomen, is the anatomical basis of strength and dynamism. abdominal, which is extremely important for maintaining optimal tone of the abdominal walls at various functional states internal organs.
The muscles of the anterior abdominal wall include 2 muscles - the rectus abdominis muscle and the pyramidal muscle, the muscles of the posterior wall - the square muscle of the lower back.
Three fascia are distinguished on the abdomen: superficial, intrinsic and transverse.
The superficial fascia separates the abdominal muscles from the subcutaneous tissue in the upper sections is weakly expressed.
Own fascia (fascia propria) forms three plates: superficial, medium and deep. The superficial plate covers the outside of the external oblique muscle of the abdomen and is most strongly developed. In the area of the superficial ring of the inguinal canal, the connective tissue fibers of this plate form fibrae intercrurales. Attaching to the outer lip of the iliac crest and to the inguinal ligament, the superficial plate covers the spermatic cord and continues into the fascia of the muscle that lifts the testicle (fascia cremasterica). The middle and deep plates of the fascia propria cover the front and back of the internal oblique muscle of the abdomen, are less pronounced.
The transverse fascia (fascia transversalis) covers the inner surface of the transverse muscle, and below the navel it covers the back of the rectus abdominis muscle. At the level of the lower abdomen, it attaches to the inguinal ligament and the inner lip of the iliac crest. The transverse fascia lines the anterior and lateral walls of the abdominal cavity from the inside, forming most of the intra-abdominal fascia (fascia endoabdominalis). Medially, at the lower segment of the white line of the abdomen, it is reinforced by longitudinally oriented bundles, which form the so-called support of the white line. This fascia, lining the walls of the abdominal cavity from the inside, according to the formations that it covers, receives special names (fascia diaphragmatica, fascia psoatis, fascia iliaca).
Topography and weak spots abdominal wall
The hypochondrium triangle is located on the anterior wall of the abdominal cavity - at the top, lateral to the rectus abdominis muscle. Its medial border is the lateral edge of the rectus abdominis muscle, the superior lateral border corresponds to the costal arch, and the lower edge is the upper edge of the tendon of the internal oblique abdominal muscle. The described triangle is strengthened weaker than other areas, since here the abdominal wall does not have a tendon extension of the internal oblique muscle of the abdomen. The triangle is occupied by fiber, in front it is covered by a tendon, less often by muscle fibers of the external oblique muscle of the abdomen and is projected onto the skin of the anterior abdominal wall in the form of a hypochondrium fossa. In the hypochondrium triangle there are VII - IX intercostal nerves, spreading in the thickness of the anterior abdominal wall. The hypochondrium triangle is used in practical medicine as a guide for finding them. Topographic information about the hypochondrium triangle is necessary when carrying out plastic surgery of the corresponding parts of the abdominal wall.
The white line of the abdomen is a ny plastic located along the median plane and limited by the medial edges of the rectus abdominis muscles. The white line extends from the xiphoid process of the sternum to the pubic symphysis. Its length in children during the first 6 months of life ranges from 9.
5-15.5 cm, in children 2 years old - 11-16.3 cm and by the age of 40 it is 30-40 cm; the width varies from 2 to 4 cm, and it decreases downward to 2-3 cm, and its thickness in the sagittal plane increases.The name "white" is associated with the color of the tendon fibers that make up it. The white line is formed by the interlacing of the tendon fibers of the aponeuroses of all the broad abdominal muscles. The significant strength that characterizes the white line is achieved by interlacing the tendons of the external oblique muscle with the tendon of the internal oblique muscle of the opposite side. Below and behind, the white line is reinforced by a "support" - a triangular-shaped bundle of fibers that is woven into the superior pubic ligament. Almost in the middle of the line is the loosened tissue corresponding to the umbilical ring.
The presence of tendon tissue along the entire length of the white line of the abdomen and the absence of muscle fibers in it reduce the possibility of resisting intra-abdominal pressure. Overstretching of tendon fibers under the influence of prolonged tension of the anterior abdominal wall is accompanied by the divergence of the fibers, as a result of which rhombic, trapezoidal and oval-shaped fissures are formed in the white line of the abdomen. The latter are usually located not along, but across the length of the white line. Most often they correspond to the places where the vascular and nerve trunks pass through the white line (branches of the intercostal nerves, small arterial branches of the superior epigastric artery). These gaps are filled, in addition to neurovascular formations, with adipose tissue associated with the subperitoneal tissue. Under unfavorable conditions (constantly increased intra-abdominal pressure), the gaps increase, and the amount of fatty tissue in it increases. Moreover, they can be filled with fatty protrusions of a round shape - fatty glands. This condition should be regarded as a certain predisposition to a hernia of the white line, since such a fatty tissue will "pull" the peritoneum behind it, and as the gap expands, the omentum and intestines will rush here. The hernial orifice is not always located strictly along the midline, they can lie on both sides of it. The upper half of the white line of the abdomen, due to the fact that it is thin and wide, is the most frequent site of hernia formation. Hernias in the lower part of the white line, where it has a significant thickness, are very rare.
The umbilical ring is an opening approximately in the middle of the white line of the abdomen between the xiphoid process and the upper edge of the symphysis. In an adult, the umbilical ring is usually located at the level of the intervertebral disc between the III and IV lumbar vertebrae. It has an irregular quadrangular shape in front, and a circle in the back. Fibers lying more superficially are associated with bundles of tendon stretching fibers of the external and internal oblique muscles of the abdomen, deeper fibers have a circular direction.
The abdominal surface of the umbilical ring is covered by the umbilical fascia in the form of a plate, in which bundles of transversely directed connective tissue fibers are clearly visible. The umbilical fascia is the intra-abdominal area that lines the entire inner surface of the abdominal walls. In men, it is better expressed. On the surface of the umbilical fascia, it is possible to identify rounded holes of various sizes, some of which allow blood vessels to pass through, while others are filled with fatty lumps that penetrate into the umbilical canal.
1. Superficial fascia of the back (fascia superficialis) is a continuation of the common superficial (subcutaneous) fascia.
2. Own fascia of the back (fascia thoracolumbalis). Divided into two sheets: superficial leaf stretches from the pelvis to the head, medially it grows together with the spinous processes of the vertebrae; deep leaf starts from the transverse processes of the lumbar vertebrae and is located only between the 12th rib and the iliac crest. Heading laterally along the lateral edge of m. erector spinae, it merges with the superficial leaf. Thus, deep autochthonous muscles above the 12th rib are embedded in a closed bone-fibrous sheath, and below the 12th rib - in a fibrous-fibrous sheath.
Behind the posterior edge of the external oblique muscle of the abdomen between it and the lower edge of m. latissimus dorsi a small gap is formed , limited inferiorly by the iliac crest - lumbar triangle, (trigonum lumbale, Petit) - the place of formation of lumbar hernias. The bottom of this triangle is the internal oblique muscle of the abdomen.
CHEST MUSCLES.
I. Muscles related to the upper limb
| 1.m. pectoralis major - pectoralis major muscle - truncopetal. | The medial half of the clavicle, the handle and the body of the sternum, the cartilage of the 2nd - 7th ribs, the anterior wall of the sheath of the rectus abdominis muscle. | Ridge of the greater tubercle humerus. | Brings the shoulder to the body, penetrates it. With fixed upper limbs, the ribs are raised, participating in the act of inhalation. | nn. pectorales lateralis et medialis. aa. intercostales post., a. thoracoacromialis, a. thoracica lateralis. | ||||
| 2. m. pectoral is minor - pectoralis minor - truncopetal | 2nd - 5th ribs. | The coracoid process of the scapula. | Pulls the scapula forward and downward, with a strengthened shoulder girdle lifts the ribs. | nn. pectorales lateralis et medialis. aa. intercostales anter., a. thoracoacromialis. | ||||
| 3.m. subclavius - subclavian muscle - truncofugal. | Cartilage of the 1st rib. | Acromial end of the clavicle. | Pulls the clavicle medially and down. | n. subclavius. a. thoracoacromialis. | ||||
| 4. m. serratus anterior - serratus anterior muscle - truncofugal. | 1st - 9th ribs. | Medial edge and inferior angle of the scapula. | Pulls the scapula laterally and down. It is an antagonist of the rhomboid muscle. | n. thoracicus longus. a. thoracica lateralis, aa. intercostales post. | ||||
| II. Autochthonous muscles of the chest. | ||||||||
| l. mm.intercostales externi - external intercostal muscles | Raise the ribs and expand the chest. | nn. intercostales. aa. intercostales post. et anter., a. musculophrenica. | ||||||
| 2.mm. intercostales interni - internal intercostal muscles. | The upper edges of the underlying ribs. | Lower edges of overlying ribs. | Lower the ribs. | The same. | ||||
| 3.mm. subcoctales - subcostal muscles | 10 to 12 ribs near their corners. | The inner surface of the overlying ribs. | Lower the ribs. | nn. intercostales. aa. intercostales post. | ||||
| 4. m. transversus thoracicis - the transverse muscle of the chest. | The inner surface of the xiphoid process. | The inner surface of the 3rd - 4th ribs. | Also. | nn. intercostales. aa. intercostales anter., a. musculophrenica. | ||||
Fascia of the breast.
1. Superficial fascia (fascia superficialis) is a continuation of the common superficial (subcutaneous) fascia, forms a sheath for the mammary gland.
2. Pectoral fascia (fascia pectoralis) consists of 2 sheets: a) superficial and b) deep. Superficial leaf (lamina superficialis) forms a case for the pectoralis major muscle (m. pectoralis major). Deep leaf (lamina profunda) covers the pectoralis minor (m. pectoralis minor) and the subclavian muscle (m. subclavius). The pectoral fascia continues into the axillary fascia (fascia axillaris).
3... Intrathoracic fascia (fascia endothoracica) covers the internal intercostal muscles (mm. intercostales intemi), the transverse muscle of the chest (m. transversus thoracis), the subcostal muscles (mm. subcostales) and the diaphragm (diaphragma).
DIAPHRAGM
Thoraco-abdominal obstruction, diaphragm (diaphragma) is a thin convex muscle plate (m. phrenicus), which is covered with serous membranes (parietal pleura, fascia endothoracica, fascia subserosa and parietal peritoneum). The diaphragmatic muscle consists of parts: 1 - lumbar; 2 - costal; 3 - sternal.
Lumbar part (pars lumbalis) has 2 legs: right (crus dextrum) and left (crus sinistrum), each of which originates from the antero-lateral surfaces of the bodies of 1-4 lumbar vertebrae. There are 2 holes between the legs: 1 - aortic opening (hiatus aorticus) for the aorta and thoracic (lymphatic) duct; 2 - esophageal (hiatus esophageus) - for the esophagus and vagus trunks.
Costal part (pars costalis) starts from the inner surface of the 6 lower ribs.
Sternum (pars sternalis) starts from the back of the sternum.
All 3 parts of the phrenic muscle are connected to a wide tendon plate - tendon center (centrum tendineum), which has opening of the inferior vena cava (foramen venae cavae inferioris).
Between the parts there are triangles (weak points), where there is no muscle and there are only the above serous membranes: right and left lumbar-costal triangles (trigonum lumbocostale dextrum et sinistrum, Larrey), right and left sternocostale triangles (trigonum sternocostale dextrum et sinistrum, Bogdaleka).
Diaphragm function: separates the abdominal and chest cavities; is a respiratory muscle.
ABDOMINAL MUSCLES.
I. Lateral muscles belly.
| Name | Start | Attachment | Function | Innervation Blood supply | ||||||
| l.m. obliquus externus abdomlnis - external oblique muscle of the abdomen. | Outside the surface of the 5th to 12th ribs. | Posterior (muscle) bundles - iliac crest; aponeurosis - the white line of the abdomen, the pubic tubercle and the anterior superior iliac spine (inguinal ligament). | Turns the body in the opposite direction. With a bilateral contraction, it lowers the ribs and flexes the spine. | nn. intercostales. n. illohypogastrlcus, n. illoingulnalls. aa. intercostales post., a. thoracica lateralis. | ||||||
| 2. m. obliquus Interims abdominis - the internal oblique muscle of the abdomen. | Iliac crest, lateral 2/3 of the inguinal ligament, thoracolumbar fascia. | Cartilage of the 10th - 12th ribs, white line of the abdomen. | Turns the body to its side. With a bilateral contraction, it lowers the ribs and flexes the spine. | nn. intercostales post., n. iliohypogastricus, n. ilioinguinalis. aa. intercostales post., a. musculophrenica, aa. epigastricae sup. et inf. | ||||||
| 3.m. transversus abdominis - transverse abdominal muscle. | Internal surfaces of the 6-12th ribs, inner lip of the iliac crest, thoracolumbar fascia, lateral 2/3 of the inguinal ligament. | White line of the abdomen. | With a bilateral contraction, the size of the abdominal cavity (the main muscle of the abdominal press) decreases. | See above. | ||||||
| II. Anterior abdominal muscles | ||||||||||
| l. m. rectus abdominis - rectus abdominis muscle. | Cartilage of the 5th - 7th ribs, the xiphoid process of the sternum. | Between the pubic ridge and the pubic symphysis. | Pulls the ribs down, flexes the spine. With a fixed chest, raises the pelvis. | nn. intercostales, n. iliohypogastricus. aa. epigastricae super. et inferior, aa. intercostales post. | ||||||
| 2. m. pyramidalis - pyramidal muscle. | Pubic ridge. | Woven into the white line of the abdomen. | Stretches the white line of the abdomen. | n. subcostalis. a. epigastrica infer. | ||||||
| III. Back muscles belly | ||||||||||
| l. m. quadratus lumborum - square muscle of the lower back. | Iliac crest, transverse processes of the lower lumbar vertebrae, ilio-lumbar ligament | 12th rib, transverse processes of the 1st - 4th lumbar vertebrae. | With a unilateral contraction, it tilts the spine to its side. With bilateral - keeps the spine in an upright position. | rr. musculares plexus lumbalis. a. subcoctalis, aa. lumbales, a.iliolumbalis. | ||||||
Fascia of the abdomen
SURFACE BACK MUSCLES
The superficial muscles of the back are attached to the skeleton of the shoulder girdle and to the humerus and are arranged in two layers (Fig. 116, 117). The first layer is made up of the trapezius muscles a and the broadest muscle of the back, the second - the large and small rhomboid muscles and the muscle that lifts the scapula.
Trapezius muscleT.trapezius, flat, triangular in shape, with a wide base facing the posterior midline, occupies upper part back and back of the neck. It begins with short tendon bundles from the external occipital protuberance, the medial third of the superior nuchal line of the occipital bone, from the nuchal ligament, spinous processes of the VII cervical vertebra and all thoracic vertebrae and from the supraspinous ligament. From the places of origin, the muscle bundles are directed, noticeably converging, in the lateral direction and are attached to the bones of the shoulder girdle. The upper bundle "and muscles pass downward and laterally, end on the posterior surface of the outer third of the clavicle. The middle bundles are oriented horizontally, pass from the spinous processes of the vertebrae outward and attach to the acromion and scapular spine. The lower bundles of muscle follow upward and laterally, pass into the tendon plate, which is attached to the scapular spine.The tendon beginning of the trapezius muscle is more pronounced at the level of the lower border of the neck, where the muscle has the greatest width.At the level of the spinous process of the VII cervical vertebra, the muscles of both sides form a well-defined tendon area, which is found in the form of an impression in a living
person.
The trapezius muscle is located superficially throughout its entire length, its upper lateral edge forms the back side of the lateral triangle of the neck. The lower lateral edge of the trapezius muscle crosses the latissimus dorsi and the medial edge of the scapula from the outside, forming the medial border of the so-called auscultation triangle. The lower border of the latter runs along the upper edge of the latissimus dorsi muscle, and the lateral border - along the lower edge of the large rhomboid muscle (the dimensions of the triangle increase when bent forward in shoulder joint hand when the scapula is displaced laterally and anteriorly).
Function: simultaneous contraction of all parts of the trapezius muscle with a fixed spine brings the scapula closer to the spine; the upper bundles of muscle raise the scapula; upper and lower bundles with simultaneous contraction. forming a pair of forces, the scapula is rotated around the sagittal axis: the lower angle of the scapula is displaced forward and laterally, and the lateral angle is displaced upward and medially. With a strengthened scapula and contraction on both sides, the muscle extends cervical spine spine and tilts the head back; with unilateral contraction - slightly turns the face in the opposite direction.
Innervation: n. Accessorius, plexus cervicalis (C m - C, v) -
Blood supply: a. transversa cervicis, a. occipitalis, a. suprascapularis, aa. intercostales posteriores.
Latissimus dorsi,T.latissimus dorsi, flat, triangular in shape, occupies the lower half of the back on the corresponding side.
The muscle lies superficially, with the exception of the upper edge, which is hidden under the lower part of the trapezius muscle. At the bottom, the lateral edge of the latissimus dorsi muscle forms the medial side of the lumbar triangle (the lateral side of this triangle is formed by the edge of the external oblique muscle of the abdomen, the lower - the iliac crest, see Fig. 117). It begins with an aponeurosis from the spinous processes of the lower six thoracic and all lumbar vertebrae (together with the superficial plate of the lumbar-thoracic fascia), from the iliac crest and the median sacral crest. The muscle bundles follow upward and laterally, converging towards the lower border of the axillary fossa. Above, muscle bundles are attached to the muscle, which start from the lower three to four ribs (they go between the teeth of the external oblique muscle of the abdomen) and ° t of the lower angle of the scapula. Covering with its lower bundles the lower angle of the scapula from behind, the latissimus dorsi muscle sharply nibbles, spirals around the large circular muscle, the posterior edge of the axillary fossa passes into a flat thick shoulder. Near the attachment site, the muscle covers the back of the vessels and nerves located in the axillary fossa. It is separated from the large round muscle by a synovial bag.
Function: brings the hand to the body and turns it inward (pronation), unbends the shoulder; lowers the raised hand; if the arms are fixed (on the horizontal bar), pulls the body to them (when climbing, swimming).
Innervation: n. Thoracodorsalis (Civ-Soup).
Blood supply: a. thoracodorsalis, a. circumflexa humeri posterior, aa. intercostales posteriores.
The muscle that lifts the scapulaT.levdior scapulae, begins with tendon bundles from the posterior tubercles of the transverse processes of the upper three or four cervical vertebrae (between the attachment points of the middle scalene muscle - in front and the belt muscle of the neck - in the back). Heading down, the muscle attaches to the medial edge of the scapula, between its upper angle and the spine of the scapula. In its upper third, the muscle is covered by the sternocleidomastoid muscle, and in the lower third by the trapezius muscle. Directly anterior to the muscle that lifts the scapula, the nerve passes to the rhomboid muscle and the deep branch of the transverse artery of the neck.
Function: raises the scapula while bringing it closer to the spine; with a reinforced scapula, it tilts the cervical part of the spine in its direction.
Blood supply: a. transversa cervicis, a. cervicalis ascendens.
Small and large rhomboid muscles,tt.rhomboidei minor et major, often grow together and form one muscle. The small rhomboid muscle starts from the lower part of the nuchal ligament, spinous processes of the VII cervical and I thoracic vertebrae and from the supraspinous ligament. Its bundles pass obliquely - from top to bottom and laterally and are attached to the medial edge of the scapula, above the level of the spine of the scapula.
The large rhomboid muscle originates from the spinous processes of the II-V thoracic vertebrae; attached to the medial edge of the scapula - from the level of the spine of the scapula to its lower angle.
The rhomboid muscles, located deeper than the trapezius muscle, themselves cover the back of the upper posterior serratus muscle and partially the muscle that straightens the spine.
Function: brings the scapula closer to the spine while moving it upward.
Innervation: n. Dorsalis scapulae (Civ-Cv).
Blood supply: a. transversa cervicis, a. suprasca-pularis, aa. intercostales posteriores.
Two thin flat muscles are attached to the ribs - the upper and lower posterior dentate (Fig. 118).
Superior posterior dentate muscle,T.serratus posterior superior, located in front of the rhomboid muscles, begins in the form of a flat tendon plate from the lower part of the nuchal ligament and spinous processes of the VI-VII cervical and I-II thoracic vertebrae. Directing obliquely from top to bottom and laterally, it is attached with separate teeth to the back surface of the II-V ribs, outward from their corners.
Function: lifts the ribs.
Innervation: nn. intercostales (Thi-Thiv).
Blood supply: aa. intercostales posteriores, a. cervi-calis profunda.
Lower posterior dentate muscle,T.serratus posterior inferior, lies in front of the latissimus dorsi muscle, begins with a tendon plate from the spinous processes of the XI-XII thoracic and I-II lumbar vertebrae; closely fused with the superficial plate of the lumbar-thoracic fascia and the beginning of the latissimus dorsi muscle. Attached by separate muscle teeth to the four lower ribs.
Function: lowers the ribs.
Innervation: pp. intercostales (Thix-Thxn).
Blood supply: aa. intercostales posteriores.
DEEPMUSCLESBACK
Deep back muscles form three layers: superficial, medium and deep. The superficial layer is represented by the belt muscle of the head, the belt muscle of the neck and the muscle that straightens the spine; the middle layer is a transverse spinous muscle; the deep layer is formed by the interspinous, intertransverse and suboccipital muscles.
The muscles of the superficial layer, belonging to the type of strong muscles, which perform mainly static work, reach the greatest development. They extend all over the back and back of the neck from the sacrum to the occipital bone. The places of origin and attachment of these muscles occupy vast surfaces and therefore, when they contract, the muscles develop great strength, keeping the spine in an upright position, which serves as a support for the head, ribs, viscera and upper limbs.
The muscles of the middle layer are oriented obliquely, spreading from the transverse processes to the spinous processes of the vertebrae. They form several layers, and in the deepest layer the muscle bundles are the shortest and are attached to the adjacent vertebrae; the more superficially the muscle bundles lie, the longer they are and the greater the number of vertebrae are thrown over (from 5 to 6).
In the deepest (third) layer, short muscles are located between the spinous and transverse processes of the vertebrae. They are not present at all levels of the spine, they are well developed in the most mobile parts of the spinal column: cervical, lumbar and lower thoracic. This - deep - layer should include the muscles located in the back of the neck and acting on the atlanto-occipital joint. They are called the suboccipital muscles.
The deep muscles of the back become visible after layer-by-layer preparation and transection of the superficial muscles: the broadest muscle of the back and the trapezius muscle - in the middle between the points of their origin and attachment (Fig. 119).
Belt muscle of the head, T.splenius capitis, located directly anterior to the upper parts of the sternocleidomastoid and trapezius muscles. It starts from the lower half of the nuchal ligament (below the level of the IV cervical vertebra), from the spinous processes of the VII cervical and the upper three to four thoracic vertebrae. 1 The bundles of this muscle run upward and laterally and are attached to the mastoid process of the "temporal bone" and to the rough platform under the lateral segment of the superior nuchal line of the occipital bone.
Function: with bilateral contraction, the muscles unbend the cervical spine and head; with a unilateral contraction, the muscle turns its head in its direction.
Innervation: posterior branches of the cervical spinal nerves (Csh - Cvin).
Belt muscle of the neck,T.splenius cervicis, starts from the spinous processes of the III-IV thoracic vertebrae. It is attached to the posterior tubercles of the transverse processes of two or three upper cervical vertebrae, covering the back of the beginning of the muscle bundles that lifts the scapula. Located in front of the trapezius muscle.
Function: while contracting, the muscles unbend the cervical spine, with unilateral contraction, the muscle turns the cervical spine in its direction.
Innervation: posterior branches of the cervical spinal nerves (Ciii-Cviii).
Blood supply: a. occipitalis, a. cervicalis profunda.
Muscle, straightening the spine, T.erector spinae. It is the strongest of the autochthonous muscles of the back, extending along the entire length of the spine, from the sacrum to the base of the skull. Lies anterior to the trapezius, rhomboid, posterior dentate muscles, latissimus dorsi. The back is covered with a superficial leaflet of the lumbar-thoracic fascia. It begins with thick and strong tendon bundles from the dorsal surface of the sacrum, spinous processes, supraspinous ligaments, lumbar, XII and XI thoracic vertebrae, posterior segment of the iliac crest and lumbar-thoracic fascia. Part of the tendon bundles starting in the sacral region merge with the bundles of the sacro-tuberous and dorsal sacroiliac ligaments.
At the level of the upper lumbar vertebrae, the muscle is divided into three paths: lateral, intermediate and medial. Each tract gets its own name: the lateral one becomes the iliocostal muscle, the intermediate one becomes the spinous muscle. Each of these muscles, in turn, is subdivided into parts.
The structural features of the muscle that straightens the spine have developed in the course of anthropogenesis in connection with upright posture. The fact that the muscle is highly developed and has a common origin on the pelvic bones, and above it is divided into separate tracts that attach widely on the vertebrae, ribs and at the base of the skull, can be explained by the fact that it performs the most important function - it keeps the body in an upright position. At the same time, the division of the muscle into separate tracts, the subdivision of the latter at different levels of the dorsal side of the body into shorter muscles with a smaller length between the points of origin and attachment, allows the muscle to act selectively. So, for example, with the contraction of the iliocostal muscle of the lower back, the corresponding ribs are pulled downwards and thereby a support is created for the manifestation of the force of the action of the diaphragm during its contraction, etc.
Iliocostal muscleT.iliocostalis (see fig. 119), is the most lateral part of the muscle that straightens the spine. It starts from the iliac crest, the inner surface of the superficial plate of the lumbar-thoracic fascia. Passes upward along the posterior surface of the ribs laterally from the corners of the latter to the transverse processes of the lower (Vii- IV) cervical vertebrae. According to the location of the individual parts of the muscle in different areas, it is subdivided into the iliocostal muscle of the lower back, the iliocostal muscle of the chest and the iliocostal muscle of the neck.
The iliocostal muscle of the lower back, i.e.iliocostalis lumbo-git, starts from the iliac crest, the inner surface of the superficial plate of the lumbar-thoracic fascia, is attached by separate flat tendons to the corners of the lower six ribs.
The iliocostal muscle of the chest, i.e.iliocostalis thoracis, starts from the six lower ribs, inwardly from the attachment points of the iliocostal muscle of the lower back. Attaches to the top six ribs at the corners and to the back of the transverse process Vii cervical vertebra.
The iliocostal muscle of the neck, i.e.iliocostalis cervicis, starts from the corners, III, IV, V and VI ribs (inwardly from the attachment points of the iliocostal muscle of the chest). Attaches to the posterior tubercles of the transverse processes of the VI-IV cervical vertebrae.
Function: together with the rest of the muscle that straightens the spine, unbends the spine; with unilateral contraction, tilts the spine to its side, lowers
ribs. The lower bundles of this muscle, pulling and strengthening the ribs, create support for the diaphragm.
Innervation: posterior branches of the cervical, thoracic and lumbar spinal nerves (Civ-Lin).
/ tx. Longest muscleT.longissimus, - The largest of the three muscles that form the erector spine. It is located medial to the iliocostal muscle, between it and the spinous muscle. It contains the longest muscles of the chest, neck and head.
The longest muscle of the chest, i.e.longissimus thoracis (see fig. 119), has the greatest extent. The muscle originates from the posterior surface of the sacrum, the transverse processes of the lumbar and lower thoracic vertebrae. Attaches to the posterior surface of the lower nine ribs, between their tubercles and corners, and to the tops of the transverse processes of all thoracic vertebrae (muscle bundles).
The longest muscle of the neck, i.e.longissimus cervicis, begins with long tendons from the tops of the transverse processes of the upper five thoracic vertebrae. Attaches to the posterior tubercles of the transverse processes VI-II cervical vertebrae.
The longest muscle of the head, i.e.longissimus capitis, begins with tendon bundles from the transverse processes I- III breast and III-Vii cervical vertebrae. It is attached to the posterior surface of the mastoid process of the temporal bone under the tendons of the sternocleidomastoid muscle and the belt muscle of the head.
Function: the longest muscles of the chest and neck unbend the spine and tilt it to the side; the longest muscle of the head unbends the last, turns the face to its side.
Innervation: posterior branches of the cervical, thoracic and lumbar spinal nerves (Cu - Lv).
Blood supply: a. cervicalis profunda, aa. inter-costales posteriores, aa. lumbales.
Spinous muscleT.spindlis (see Fig. 119) - the most medial of the three parts of the muscle that straightens the spine. It is adjacent directly to the spinous processes of the thoracic and cervical vertebrae. In it, respectively, the spinous muscle of the chest, the spinous muscle of the neck and the spinous muscle of the head are distinguished.
Spinous muscle of the chestm. spindlis thoracis, begins with 3-4 tendons from the spinous processes II and I lumbar, XII and XI thoracic vertebrae. Attaches to the spinous processes of the upper eight thoracic vertebrae. The muscle is fused with the deep-lying semispinal muscle of the chest.
Spinous muscle of the neckm. spinalis cervicis, starts from spinous processes I and II breast Vii cervical vertebra and the lower segment of the nuchal ligament. Attaches to the spinous process II(sometimes III and iv) the cervical vertebra.
Spinous muscle of the headm. spinalis capitis, begins in thin bundles from the spinous processes of the upper thoracic and lower cervical vertebrae, rises up and attaches to the occipital bone near the external occipital protuberance. Often this muscle is missing.
Function: unbends the spine
Innervation: posterior branches of the cervical, thoracic and upper lumbar spinal nerves (Csh-Ln).
Blood supply: a. cervicalis profunda, aa. inter-costales posteriores.
The function of the whole muscles that straighten the spine,T.erector spinae, accurately reflects its name. Since the constituent parts of the muscle originate in the vertebrae, it can act as an extensor of the spine and head, antagonizing the anterior muscles of the trunk. Contracting in separate parts on both sides, this muscle can lower the ribs, unbend the spine, and throw the head back. With a unilateral contraction, it tilts the spine in the same direction. The muscle also exhibits great strength during torso flexion, when it performs inferior work and prevents the body from falling forward under the action of the ventrally located muscles, which have a greater leverage on the spinal column than the dorsally located muscles.
Transverse spinous muscleT. transversospindlis . This muscle is represented by a multitude of layered muscle bundles that run obliquely upward from the lateral to the medial side from the transverse to the spinous processes of the vertebrae. The muscle bundles of the transverse spinous muscle are of unequal length and, spreading over a different number of vertebrae, form separate muscles: semi-awn, polyparticle and rotator cuff muscles.
At the same time, respectively, the occupied area along the spinal column, each of these muscles, in turn, is subdivided into separate muscles, named after their location on the dorsal side of the trunk, neck and occipital region. In this sequence, the individual parts of the transverse spinous muscle are considered.
Semispinal muscleT.semispinalis, looks like long muscle bundles, starts from the transverse processes of the underlying vertebrae, spreads over four to six vertebrae and attaches to the spinous processes. It is divided into semispinal muscles of the chest, neck and head.
Semispinal muscle of the chest,m. semispinalis thoracis, starts from the transverse processes of the lower six thoracic vertebrae; attaches to the spinous processes of the four upper thoracic and two lower cervical vertebrae.
Semispinal muscle of the neck, i.e.semispinalis cervicis, originates from the transverse processes of the six upper thoracic vertebrae and the articular processes of the four lower cervical vertebrae; attached to the spinous processes of the V-II cervical vertebrae.
Semispinal muscle of the head,m. semispinalis capitis, wide, thick, starts from the transverse processes of the six upper thoracic and articular processes of the four lower cervical vertebrae (outward from the long muscles of the head and neck); attaches to the occipital bone between the superior and inferior nuchal lines. The muscle behind is covered by the belt and longest muscles of the head; deeper and in front of it lies the semispinal muscle of the neck.
Function: the semispinal muscles of the chest and neck unbend the thoracic and cervical spine; with unilateral contraction, these sections are turned in the opposite direction. The semispinal muscle of the head throws the head back, turning (with a one-sided contraction) the face in the opposite direction.
Innervation: posterior branches of the cervical and thoracic spinal nerves (Csh-Thxii).
Blood supply: a. cervicalis profunda, aa. intercos-tales posteriores.
Multipart musclesmm. multifidi, are muscle-tendon bundles that start from the transverse processes of the underlying vertebrae and attach to the spinous processes of the overlying ones. These muscles, spreading over two to four vertebrae, occupy the grooves on the sides of the spinous processes of the vertebrae along the entire length of the spinal column, from the sacrum to the II cervical vertebra. They lie directly in front of the semispinal and longissimus muscles.
Function: rotate the spinal column around its longitudinal axis, participate in extension and tilt it to the side.
Innervation: posterior branches of the spinal nerves (C „, - Si).
Blood supply: a. cervicalis profunda, aa. inter-costales posteriores, aa. lumbales.
Muscles - rotators of the neck, chest and lower back,tt.rotatores cervicis, thoracis et lumborum, make up the deepest layer of the musculature of the back, occupying the groove between the spinous and transverse processes. The rotator cuff muscles are better expressed within the thoracic spine. Accordingly, the length of the bundles of the rotator muscles are divided into long and short. The long rotator cuffs start from the transverse processes and attach to the bases of the spinous processes of the overlying vertebrae, spreading over one vertebra. Short rotator cuff muscles are located between adjacent vertebrae.
Function: rotate the spinal column around its longitudinal axis.
Blood supply: a. cervicalis profunda, aa. intercos-tales posteriores, aa. lumbales.
Interspinous muscles of the neck, chest and lower back,tt.interspi- nales cervicis, thordcis et lumborum, connect the spinous processes of the vertebrae to each other, starting from the II cervical and below. They are better developed in the cervical and lumbar regions of the spinal column, which are characterized by the greatest mobility. In the thoracic part of the spine, these muscles are weakly expressed (may be absent).
Function: participate in the extension of the corresponding parts of the spine.
Innervation: posterior branches of the spinal nerves.
Blood supply: a cervicalis profunda, aa. intercos-tales posteriores, aa. lumbales.
Intertransversemuscleloins, breastsandneck, mm, intertransversarii lumborum, thordcis et cervicis, represented by short beams, spreading between the transverse processes of adjacent vertebrae. Better expressed at the level of the lumbar and cervical spine.
The intertransverse muscles of the lower back are subdivided into lateral and medial, tt.intertransversarii laterdles et media tes lumborum. In the neck area, the anterior (they are thrown between the anterior tubercles of the transverse processes) and the posterior intertransverse muscles of the neck are distinguished, tt.intertransversarii anteriores et posteriores cervicis. The latter have a medial part, pars medialis, and lateral part, pars lateralis.
Function: tilt the corresponding parts of the spinal column to their side.
Innervation: posterior branches of the cervical, thoracic and lumbar spinal nerves.
Blood supply: a. cervicalis profunda, aa. intercosta-les posteriores, aa. lumbales.
FASCES OF THE BACK
The superficial fascia covering the trapezius and latissimus dorsi is weak. The loco-thoracic fascia is well developed, fascia thoracolumbalis, which covers the deep muscles of the back.
At different levels, this fascia is expressed differently. It is most developed in the lumbar region, where it is represented by the superficial and deep plates that form the fascial sheath for the muscle that straightens the spine.
The superficial plate of the lumbar-thoracic fascia is attached to the spinous processes of the lumbar vertebrae, to the supraspinous ligaments and to the median sacral ridge. The deep plate of this fascia from the medial side is attached to the transverse processes of the lumbar vertebrae and intertransverse ligaments, below - to the iliac crest, above - to the lower edge of the XII rib and the lumbar-costal ligament.
At the lateral edge of the muscle that straightens the spine, the superficial and deep plates of the lumbar-thoracic fascia are combined into one. A deep plate of the thoracic lumbar fascia separates the erector muscle from the square muscle of the loin. Within the chest wall, the lumbar-thoracic fascia is represented by a thin plate that separates the erector muscle from the more superficial muscles. Medially, this fascia is attached to the spinous processes of the thoracic vertebrae, laterally - to the corners of the ribs. In the posterior (nuchal) region of the neck, between the muscles located here, there is a nuchal fascia, fascia nuchae
Own fascia of the back, fascia thoracolumbalis. Divided into two sheets: superficial leaf stretches from the pelvis to the head, medially it grows together with the spinous processes of the vertebrae; deep leaf starts from the transverse processes of the lumbar vertebrae and is located only between the 12th rib and the iliac crest. Heading laterally along the lateral edge of m. erector spinae, it merges with the superficial leaf. Thus, deep autochthonous muscles are embedded in a closed osteo-fibrous sheath.
Behind the posterior edge of the external oblique muscle of the abdomen between it and the lower edge of m. latissimus dorsi a small gap is formed - lumbar triangle, trigonum lumbale, limited from below by the iliac crest. The bottom of this triangle is the internal oblique muscle of the abdomen.
MUSCLES AND BREAST FASCES
Chest area at the top it is limited by the jugular notch of the sternum and clavicles, at the bottom - by a line passing through the xiphoid process, costal arches towards the XII thoracic vertebra.
The muscles of the chest are divided into muscles that begin on the surface of the chest and go to the bones of the upper limb, and into their own (autochthonous) muscles of the chest, starting deep from the walls of the chest cavity.
Muscles of the chest related to the upper limb.
1. The pectoralis major muscle, m. pectoralis major(truncated). Muscle start: from the medial half of the clavicle, the anterior surface of the sternum and cartilage of the 2nd - 3rd ribs, the anterior wall of the sheath of the rectus abdominis muscle. Muscle Attachment: short tendon to the crest of the greater tubercle of the humerus. Function: brings the upper limb to the body and turns it inward; with fixed upper limbs, it can raise the ribs with the sternum and thereby facilitate the act of inhalation.
2. Small pectoral muscle, m. pectoralis minor- (truncopetal). Lies under the pectoralis major muscle. Muscle start: begins with four teeth from the 2nd to the 5th rib. Muscle Attachment: to the coracoid process of the scapula. Function: pulls the scapula forward and down; with fixed hands, it acts as an inspiratory muscle.
3. Subclavian muscle, m. subclavius(truncofugal). Muscle start: the lower surface of the clavicle. Muscle Attachment: 1st rib. Function: strengthens the sternoclavicular joint, pulls the clavicle down and medially.
4. Serratus anterior muscle, m. serratus anterior(truncofugal). Muscle start: nine upper ribs. Muscle Attachment: the medial edge of the scapula. Function: presses the shoulder blade to the body and rotates the shoulder blade.
Own (autochthonous) muscles of the chest.
5. External intercostal muscles, mm. intercostales externi. Muscle start: the bottom edge of each rib. Muscle Attachment: the upper edge of the underlying rib. Muscles do not reach the sternum. Function: lifts the ribs.
6. Internal intercostal muscles, mm. intercostales interni. They lie under the external muscles and have the opposite direction of the fibers with the latter, intersecting with them at an angle. Muscle start: the upper edge of the underlying rib. Muscle Attachment: the lower edge of the overlying rib. Function: lowers the ribs.
The autochthonous muscles of the chest also include subcostal (mm. subcostales) and transverse (m. transversus thoracis) muscles... They are located on the inner surface of the chest cavity. Function: participate in the lowering of the ribs.
Fascia and breast topography.
Superficial layer of the fascia of the chest, fascia pectoralis medially and above, respectively, passes into the periosteum of the sternum and clavicle, and laterally - into deltoid fascia, fascia deltoidea. The superficial layer separates the pectoralis major muscle from the mammary gland.
Deep leaf fascia pectoralis, splitting and re-connecting, surrounds the subclavian and pectoralis minor muscles. Both layers of the deep fascia of the chest are connected in the area of the sulcus deltoideopectoralis. Above the upper edge of the pectoralis minor muscle, the fascia pectoralis thickens and is called fascia clavipectoralis. In the area of the lower edge of the pectoralis major muscle, it passes into the axillary fossa and is called fascia axillaris. The inner surface of the chest is lined with an intrathoracic fascia, fascia endotoracica.
Abdominal obstruction, diaphragma.
Abdominal obstruction, diaphragma is a dome-shaped flat muscle (m. phrenicus - literally - "mental muscle"), covered above and below by fascia and serous membranes. Muscle fibers, starting around the entire circumference of the lower opening of the chest, rise up and pass into a tendon extension, called the tendon center, centrum tendineum. At the place of origin of fibers in the muscular part of the abdominal obstruction, the lumbar, costal and sternal parts are distinguished.
Lumbar part, pars lumbalis consists of several bundles of fan-shaped muscles, is divided into two legs (left and right), which, in turn, can be divided into three bundles, or legs: crus laterale, crus intermedius and crus mediale. The legs cover the region of the four upper lumbar vertebrae and the last pair of ribs. The medial pedicles are more pronounced, thicker and longer. The right one starts from the body of the fourth lumbar vertebra, the left one starts from the third vertebra. Crus intermedius starts from the body of the second lumbar vertebra, a crus lateralis - from the body of the first or second lumbar vertebra and goes to its transverse process, forming a lig. arcuatum mediale, and from the transverse process to the free edge of the 12th rib, forming lig. arcuatum laterale. Under lig. arcuatum mediale pass m. psoas major et minor, under lig. arcuatum laterale - m. quadratus lumborum.
Costal part, pars costalis, starting from the cartilage of the VII-XII ribs, it passes into the tendon part.
Sternum, pars snernalis, departs from the posterior surface of the xiphoid process of the sternum to the tendon center. Near the sternum, between the sternum and costal parts of the muscles, a paired sternocostal triangle, tpigonum sternocostale (the final branch of the internal thoracic artery passes - the superior epigastric artery). Between the lumbar and costal parts there is lumbar-costal triangle, trigonum lumbocostale. Both triangles are weak points of the diaphragm (the likelihood of passing so-called diaphragmatic hernias).
MUSCLES AND FASCES OF THE ABDOMINAL
Belly, abdomen- the part of the body located between the chest and the pelvis and is bounded from above by a line passing through the xiphoid process and costal arches, below by the iliac crests, inguinal folds, from the sides by the posterior axillary lines.
Most of the abdominal muscles are broad and long muscles. Their tendon sprains (aponeurosis) are found along the anterior midline of the abdomen with the same sprains of the muscles of the opposite side, forming the white line of the abdomen, linea alba. It stretches from the xiphoid process of the sternum to the pubic symphysis.
The abdominal muscles are divided into the following groups: lateral, anterior and posterior. They belong to the autochthonous ventral muscles, innervated by the intercostal nerves (V - XII) and the upper branches of the lumbar plexus.
Side group.
1. External oblique muscle of the abdomen, m. obliquus externus abdominis. The most superficial abdominal muscle. Muscle start: eight lower ribs. The fibers of the muscle are, as it were, a continuation of the external intercostal muscles and go in the same direction obliquely from top to bottom and from back to front. Muscle Attachment: the posterior bundles are attached to the iliac crest, the anterior ones pass into a wide aponeurosis, which connects along the midline of the abdomen with the same aponeurosis of the other side, participating in the formation of the anterior wall of the sheath of the rectus abdominis muscle and linea alba.
The lower free edge of the aponeurosis spreads between spina iliaca anterior superior and tuberculum pubicum, forming inguinal ligament, lig. inguinale (Pouparti)(for more details see "Inguinal canal").
2. Internal oblique muscle of the abdomen, m. obliquus internus abdominis. Lies under the external oblique muscle of the abdomen. Muscle start: thoracolumbar fascia, iliac crest, lateral 2/3 of the inguinal ligament. Muscle Attachment: to the lower edge of the three lower ribs. The anterior muscle bundles pass into a wide aponeurosis, which splits into two sheets along the lateral edge of the rectus abdominis muscle, which take part in the formation of the sheath of the rectus abdominis muscle.
3. Transverse abdominal muscle, m. transversus abdominis. The deepest of the lateral wide abdominal muscles. Muscle start: the inner surface of the six lower ribs, a deep leaf of the thoracolumbar fascia (fascia thoracolumbalis) and the outer 2/3 of the inguinal ligament. The anterior beams pass into a wide aponeurosis, which, heading to the linea alba in the upper section, behind, and in the lower, in front of m. rectus abdominis, forms the sheath of the rectus abdominis muscle. On the inner surface facing the abdominal cavity, the transverse abdominal muscle is covered fascia transversalis, which is a section of the common abdominal fascia (fascia subperitonealis). The latter lines the entire inner surface of the abdominal walls and is called, respectively, the area of location.
Front group.
4. The rectus abdominis muscle, m. rectus abdominis. Lies on the side of the anterior midline and consists of longitudinal muscle bundles running in the vertical direction. The muscle begins from the anterior surface of the 5th, 6th, 7th costal cartilage and the xiphoid process of the sternum. The tendon attaches to the pubic bone. The muscle is interrupted by 3 - 4 tendon bridges, intersectiones tendineae, which grow together with the anterior wall of the vagina (see "Sheath of the rectus abdominis muscle"). The bridges are traces of the former segmental development of the ventral muscles.
Function: the listed abdominal muscles by uniform contraction of fibers located in mutually perpendicular directions, with the participation of the diaphragm, exert pressure on the abdominal organs. Thus, the muscles play the role of the so-called abdominal, prelum abdominale, contributing to the emptying of organs during the act of defecation, vomiting, etc., as well as during the act of childbirth and breathing. Here m plays an important role. transversus abdominis. The action of these muscles on the spinal column and the skeleton as a whole is important and varied. Approaching the chest to the pelvis, they flex the spinal column, being antagonists of the longitudinal muscles of the back. Oblique muscles with unilateral contraction rotate the chest; while the internal oblique muscle turns the chest in its direction, together with the outer opposite side. For example, the rotation of the chest to the right occurs with simultaneous contraction of the left external and right internal oblique muscles.
5. Pyramidal muscle, m. pyramidalis. It lies under the anterior wall of the rectus sheath above the pubic fusion and attaches to the white line of the abdomen, which it stretches during contraction.
6. Square muscle of the lower back, m. quadratus lumborum. Muscle start: from the iliac crest and lig. iliolumbale. Muscle Attachment: to the transverse processes of the 1st, 2nd lumbar vertebrae and to the 12th rib. Function: fixes the 12th rib and lumbar spine and tilts the torso to the side.