chest muscles. The proper musculature of the thoracic region of the body, lying in depth, retains, like the skeleton of this region, a segmental structure. Muscles are arranged in three layers: 1) external intercostal; 2) internal intercostal; 3) transverse muscle chest. The diaphragm is also functionally connected with these muscles.
External intercostal muscles occupy all the intercostal spaces from the spine to the costal cartilages. Their fibers go from top to bottom and forward. Since the lever arm (lever of force) at the point of attachment of the muscle is longer than at the point of its beginning, when the muscles contract, they raise the ribs, increasing the volume of the chest in the anteroposterior and transverse directions. This is one of the main muscles of inspiration. Their most dorsal bundles, originating from the transverse processes of the thoracic vertebrae, stand out as the muscles that lift the ribs.
Internal intercostal muscles occupy the anterior 2/3 of the intercostal spaces. Muscle fibers are directed from bottom to top and forward, therefore, by contracting, they lower the ribs and, by reducing the size of the chest, contribute to exhalation.
Transverse chest muscle located from inside chest wall. Muscle contraction promotes exhalation.
The fibers of the own muscles of the chest lie in three intersecting directions. This structure strengthens the chest wall.
chest muscles(A - front view. B - pectoralis major muscle removed. C - internal intercostal muscles removed). 1 - deltoid muscle (m. deltoideus); 2 - pectoralis major muscle (m. pectoralis major); 3 - external oblique muscle of the abdomen (m. obliquus externus abdominis); 4 - serratus anterior muscle (m. serratus anterior); 5 - subclavian muscle (m. subclavius); 6 - internal intercostal muscles (mm. intercostales interni); 7 - pectoralis minor (m. pectoralis minor); 8 - latissimus dorsi (m. latissimus dorsi); 9 - external intercostal muscles (mm. intercostales externi); 10 - transverse muscle of the chest (m. transversus thoracis)
The diaphragm, or abdominal obstruction, separates the abdominal cavity from the chest. The muscle develops in the early embryonic period from the cervical myotomes and, as the heart and lungs form, moves back until it takes its permanent place in the three-month-old fetus. According to the place of laying, the muscle is supplied with a nerve extending from the cervical plexus.
The diaphragm is domed. It consists of muscle fibers that start around the entire circumference of the lower opening of the chest and pass into the tendon center, which occupies the top of the dome. On the middle left part of the dome is the heart. The thoracic obstruction is perforated by holes through which the aorta, esophagus, veins, lymphatic duct, and nerve trunks pass. The diaphragm serves as the main respiratory muscle. During contraction, its dome falls and the vertical size of the chest increases. In this case, the lungs are mechanically stretched and inhalation is carried out.
Thus, the main function of these muscles is participation in the mechanism of respiration. Muscles that increase the volume of the chest cause inhalation. At different people it is carried out either mainly due to external intercostal muscles(thoracic type of breathing), or due to the diaphragm (abdominal). Breath patterns are not strictly constant and can change. Muscles that reduce the volume of the chest, work only with increased exhalation. Usually, the plastic properties of the chest are sufficient for exhalation.
pectoralis major muscle originates from the sternal part of the clavicle, from the edge of the sternum and from the cartilages of the upper 5-6 ribs. The muscle is attached to the crest of the large tubercle of the humerus. Between the last and the muscle tendon lies the synovial bag. Contracting, the muscle adducts and penetrates the shoulder, pulling it forward.
pectoralis minor muscle located under the big one. It starts from the II-V ribs, attaches to the coracoid process and, when contracted, pulls the scapula down and forward.
The serratus anterior muscle begins with nine teeth on the II-IX ribs. It is attached to the medial edge of the scapula and to its lower corner, with which most of its bundles are connected. During contraction, the muscle pulls the scapula forward, and its lower angle outwards, due to which the scapula rotates around the sagittal axis and the lateral angle of the bone rises. If the arm is abducted, the serratus anterior, by rotating the scapula, raises the arm above the level of the shoulder joint. Now the arm moves along with the shoulder girdle in the sternoclavicular joint.
Fascia of the chest are mostly poorly developed.
Muscles of the anterior wall of the chest behind(A) and right inguinal region(B)
Muscles of the chest and abdomen. 1 - pectoralis minor (m. pecforalis minor); 2 - internal intercostal muscles (mm. intercostales interni); 3 - external intercostal muscles (mm. intercostales externi); 4 - rectus abdominis (m. rectus abdominis); 5 - internal oblique muscle of the abdomen (m. obliquus internus abdominis); 6 - transverse abdominal muscle (m. transversus abdominis); 7 - external oblique muscle of the abdomen (m. obliquus externus abdominis); 8 - aponeurosis of the external oblique muscle of the abdomen; 9 - serratus anterior muscle (m. serratus anterior); 10 - pectoralis major (m. pectoralis major); 11 - deltoid muscle (m. deltoideus); 12 - subcutaneous muscle of the neck (platysma)
Abdominal muscles. The abdominal wall is formed by a group of own muscles. These include rectus abdominis, pyramidal muscle, quadratus lumborum And broad abdominal muscles- external and internal oblique and transverse. Broad muscles lie in the side walls of the abdomen. The tendon fibers of their aponeuroses, intertwining in front, form a white line of the abdomen in the middle of the abdominal wall, which is strengthened at the top on the xiphoid process of the sternum, and at the bottom - on the pubic symphysis. On the sides of the white line is the rectus abdominis muscle with a longitudinal direction of the fibers. The broad muscles have an oblique direction of the fibers and lie, as on the chest, in three layers, and the external oblique muscle of the abdomen is a continuation of the external intercostal muscles, the internal oblique is the internal intercostal muscles, and the transverse abdominal muscle is of the chest muscle of the same name. Square muscle of the lower back forms the posterior abdominal wall. The lower wall of the abdominal cavity, or the bottom of the small pelvis, is called the perineum.
rectus abdominis originates from the cartilages of the V-VII ribs and the xiphoid process, attaches outwards from the pubic symphysis. It is intercepted across by three or four tendon bridges. The rectus muscle is located in the fibrous sheath, which is formed by the aponeuroses of the oblique muscles of the abdomen.
Pyramidal muscle small, often absent. This is a rudiment of the pouch muscle of mammals. Starting near the pubic symphysis and tapering upward, the muscle attaches to the white line, pulling it on during contraction.
External oblique abdominal muscle originates in eight bundles from the lower ribs. Its fibers go from top to bottom and forward, attaching to the iliac crest. In front, the muscle passes into the aponeurosis, the fibers of which take part in the formation of the sheath of the rectus muscle; along the midline, they intertwine with the fibers of the aponeuroses of the oblique muscles of the other side, forming a white line. The lower free edge of the aponeurosis is tucked inward, thickened and forms an inguinal ligament, the ends of which are fixed on the anterior superior iliac spine and pubic tubercle.
Internal oblique abdominal muscle starts from the thoracolumbar fascia, iliac crest and inguinal ligament, goes from bottom to top and forward, attaches to the three lower ribs. The lower muscle bundles pass into the aponeurosis, which is part of the sheath of the rectus muscle and the white line of the abdomen.
transverse abdominis muscle starts from the lower ribs, thoracolumbar fascia, iliac crest and inguinal ligament, in front passes into the aponeurosis, which takes part in the formation of the sheath of the rectus muscle and the white line. The lowest bundles of the last two muscles in the spermatic cord descend into the scrotum, where they cover the testicle. These bundles are called the muscle that suspends the testis.
Muscles of the trunk from the side: A - surface layer; B - the pectoralis major muscle and the external oblique of the abdomen have been removed; B - removed pectoralis minor, latissimus dorsi and internal oblique abdomen, opened the vagina of the rectus abdominis muscle
The abdominal muscles perform a variety of functions. They form the wall of the abdominal cavity and, due to their tone, hold the internal organs. When contracting, they narrow the abdominal cavity (mainly the transverse abdominal muscle) and act on the internal organs as an abdominal press, contributing to the excretion of urine, feces and vomit, coughing, and childbirth. The abdominal muscles pull the ribs down, reducing the size of the chest cavity and thereby participating in the exhalation. Finally, these muscles flex the spine forward (mainly the rectus abdominis), laterally, and rotate around the longitudinal axis. The last movement is carried out with the simultaneous contraction of the versatile external and internal oblique muscles, and the turn is made towards the internal oblique, which begins on the ilium bones fixed when the person is standing.
The square muscle of the lower back, starting from the iliac crest, is attached to the transverse processes of the lumbar vertebrae and the XII rib. The muscle pulls the rib down, taking part in the exhalation, and bends the spine back and to the sides.
The muscles of the perineum, supporting the abdominal organs from below, function simultaneously as sphincters of the anus and urethra.
Of the fascia covering the muscles of the abdominal wall, the most dense is the intra-abdominal fascia, which lines the inner surface of the abdominal wall. Fascia is involved in the formation of the posterior wall of the vagina of the rectus muscle and the inguinal canal. From the inside, the fascia is covered with peritoneum.
The mutual intersection of the fibers of the broad muscles, the fibrous sheath around the rectus muscle, its tendon bridges - all this strengthens the soft wall of the abdomen. But some features of the structure of the abdominal wall lead to the fact that there are “weak spots” in it, which may be the site of hernia formation. A hernia is called an exit internal organs- intestines, stomach, greater omentum, kidney, ovary - from the abdominal cavity through a natural or artificially enlarged opening along with the peritoneum lining the abdominal cavity, mainly under the skin of the abdomen. The causes of hernias are weakness of the muscles or a sharp emaciation, combined with a prolonged increase in intra-abdominal pressure: prolonged constipation, crying in infants, lifting excessive weights, etc. Hernias appear in weak points abdominal wall that cannot withstand intra-abdominal pressure.
Hernias can occur in the region of the white line when its fibrous fibers diverge, at the site of the navel, which is a scar after transection in a newborn umbilical cord. Inguinal hernias are formed when organs protrude through the inguinal canal. The latter lies above the inguinal ligament and is a muscular gap through which the spermatic cord passes in men, and the round ligament of the uterus in women. Femoral hernias occur when organs protrude under the skin below the inguinal ligament. Here, between the ligament and the pelvic bone, blood and lymphatic vessels pass to the thigh, and loose connective tissue and lymph nodes lie medially from them. This area is, under certain conditions, passable for the internal organs.
Diaphragm, muscles of the back wall of the abdomen and pelvis. On the right, the square muscle of the lower back and partially the psoas muscle were removed
back muscles. On the back, as well as on the chest, own muscles lie in depth and are covered with muscles that set the upper limbs in motion and strengthen them on the body. The ventral musculature of the back includes two underdeveloped muscles ending in the ribs: rear upper And rear lower serrated.
Serratus posterior superior originates from the spinous processes of the two lower cervical and two upper thoracic vertebrae.
Serratus posterior inferior starts from the thoracolumbar fascia at the level of the two lower thoracic and two upper lumbar vertebrae.
Both muscles are involved in the respiratory act, lifting the upper and lowering the ribs. Acting simultaneously, they stretch chest.
Under both posterior serratus muscles along the spinal column lie the deep muscles of the back. These are the intrinsic muscles of the trunk, which are of dorsal origin. In humans, they retain a primitive, more or less metameric arrangement. Deep back muscles lie on both sides of the spinous processes of the spine, extending from the sacrum to the skull. Four tracts can be distinguished in them, successively located in the depth direction.
I tract(only on the neck) is represented by the belt muscle of the head and neck, which starts from the spinous processes of the upper thoracic and lower cervical vertebrae and is attached to the transverse processes of the I and III cervical vertebrae and to the mastoid process of the temporal bone. With bilateral contraction, the muscle flexes the head and neck backward; with one-sided - turns them.
II tract It is formed by the rectifier of the spine, which starts from the posterior surface of the sacrum, the spinous processes of the lumbar vertebrae, the posterior part of the iliac crest, and the thoracolumbar fascia. The muscle extends the spine and plays a large role in its statics.
Below the XII rib, the rectus vertebrae is divided into three muscles: the iliocostal, longissimus and spinous muscles of the back.
The iliocostal muscle is the most lateral, attached to the ribs and transverse processes of the lower cervical vertebrae.
The longissimus dorsi muscle is attached to the transverse processes of all the thoracic and cervical vertebrae and ends on the mastoid process of the temporal bone.
The spinous muscle of the back is attached to the spinous processes of the thoracic and cervical vertebrae up to the axial vertebra.
III tract comprises transverse spinous muscle, which stretches from the sacrum to the occipital bone, and its bundles are directed from the transverse processes to the spinous. The muscles of this tract produce extension of the spine, tilt it to the sides, and also rotate it.
IV tract form short muscles of the back: transverse and interspinous in the cervical and lumbar regions (ventral origin), occipital-vertebral muscles.
Deep back muscles: left - lumbar-dorsal fascia and serratus posterior muscles; on the right - I and II tracts of the deep muscles of the back
Deep back muscles: left - rectifier of the spine; on the right - the short muscles of the occiput and the transverse spinous muscle
The transverse muscles are located between the transverse processes of adjacent vertebrae; during contraction, they are involved in the abduction of the spine to the sides.
The interspinous muscles are located between the spinous processes of neighboring vertebrae; involved in the extension of the spine.
Short occipital-vertebral muscles in the amount of four are located between the occipital bone, atlas and axial vertebra. The muscles extend and rotate the head.
The variety of deep muscles of the back is associated with a great differentiation of movements of the spine and the whole body. The power of this muscle ensures the vertical position of a person. Without the deep back muscles, the human torso would bend forward, as its center of gravity lies in front of the spine.
The group of back muscles associated with the upper limbs is located in two layers. IN surface layer lie trapezius muscle(visceral, beginning on the head) and latissimus dorsi muscle- parietal.
trapezius muscle originates from the superior nuchal line of the occipital bone, nuchal ligament and spinous processes of all thoracic vertebrae. Muscle fibers converge outward and attach to the outer end of the clavicle, to the spine and acromial process of the scapula. The lower muscle bundles, contracting, lower the shoulder girdle, the middle ones pull it towards the spine, the upper ones raise it; the upper bundles work as synergists with the serratus anterior when it abducts the arm above the level of the shoulder joint. With a fixed shoulder girdle, the trapezius muscle pulls the head back.
Latissimus dorsi muscle starts from the thoracolumbar fascia, from the spinous processes of 4-6 lower thoracic vertebrae and all lumbar, 4 lower ribs and the iliac crest. Muscle fibers converge outwards and upwards, where they are attached by a flat tendon to the crest of the lesser tubercle of the humerus. Between the tendon and the tubercle lies the synovial sac. The muscle leads the hand, penetrates and pulls it back.
Under the trapezius muscle, therefore, in second layer, lie rhomboid muscle And levator scapula.
Rhomboid muscle starts from the spinous processes of the two lower cervical vertebrae and the four upper thoracic vertebrae, is attached to the medial edge of the scapula, which is pulled medially and upward during contraction.
Muscle that lifts the scapula, starts from the transverse processes of the upper cervical vertebrae and is attached to the upper corner of the scapula, which, with its contraction, pulls upward, simultaneously lowering its lateral angle.
Superficial back muscles: left - first layer; right - second layer
The muscles of the upper limb, located on the body, in addition to the described meaning, have another thing. So, the muscles attached to the shoulder blade not only set it in motion. With simultaneous contraction of antagonistic muscle groups, they fix the scapula. In addition, if a limb is immobilized by the tension of other muscles, then, by contracting, they no longer act on the limb, but on the chest, expanding it, i.e., they function as auxiliary muscles of inspiration.
These muscles are used by the body during increased or difficult breathing, such as when running, physical work, or with certain diseases of the respiratory organs.
Of the fasciae of the back, one thoracolumbar is well developed, covering the deep muscles in front and behind. Growing with its deep leaf to the transverse processes of the lumbar vertebrae, and superficial to the spinous processes of almost all vertebrae, it forms a bone-fibrous canal of these muscles. The latissimus dorsi, serratus posterior inferior, transverse and internal oblique muscles of the abdomen originate from a superficial, especially durable sheet of fascia.
The muscles and fascia of the body are divided according to their location into suboccipital muscles, muscles of the back, chest, abdomen And perineum. The muscles of the body are paired and are located symmetrically - on the right and on the left. Development of the muscles of the trunk Skeletal muscles appear at the 4th week of embryonic development from myotomes. Myotome cells - myoblasts - differentiate and turn into striated skeletal muscle fibers. The dorsal part of the myotomes, located next to the spinous processes of the vertebrae, gives rise to the muscles of the back; from the ventral part of the myotomes, the muscles of the neck, chest, and abdomen are formed.
Subsequently, a connective tissue septum grows into the myotomes, dividing them into superficial and deep layers and, accordingly, muscle groups. Simultaneously with the development of the muscles of the back, the formation of a connective tissue cover - fascia. The most developed and well-defined
thoracic fascia. The diaphragm is formed from the cervical myotomes. The resulting muscular rudiments of the diaphragm in the neck move down, where, merging, they form a muscular-tendon plate that closes the lower aperture of the chest.
back musclesBack(dorsum)- back surface of the trunk and neck; at the top it includes
vyyu- the back surface of the neck and reaches the external occipital protrusion, from below it is limited by the lateral edges of the sacrum, coccyx and iliac crests, laterally - by the posterior axillary line. The muscles of the back are divided into two groups by origin and position:
superficial, including muscles
shoulder girdle, - truncopetal (i.e., in the process of development, moved from the limb to the body), as well as muscles attached to the ribs, and
deep, formed from the dorsal parts of myotomes, i.e. autochthonous.
Rice. 54.1. Back muscles: 1 - latissimus dorsi; 2 - trapezius muscle; 3 - semispinalis muscle of the head; 4 - belt muscle of the head; 5 — the muscle lifting a scapula; 6 - serratus posterior superior; 7 - large rhomboid muscle; 8 - muscle straightening the spine; 9 - lower posterior serratus muscle The superficial muscles of the back are separated from the deep ones by a well-defined lumbar-thoracic fascia (Fig. 54).
Superficial back muscles 1.
trapezius muscle(m. trapezius) has a triangular shape; its base is facing the spinous processes of the vertebrae, and the apex
Rice. 54.2. Deep muscles of the back: 1 - internal oblique muscle of the abdomen; 2 - serratus posterior inferior; 3 - serratus posterior superior; 4 - belt muscle of the head; 5 - semispinalis muscle of the head; 6 - a small posterior rectus muscle of the head; 7 - a large posterior rectus muscle of the head; 8 and 9 - upper and lower oblique muscles of the head; 10 - the longest muscles of the head; 11 - spinous muscle of the head; 12 - the longest muscle; 13 - iliac costal muscle; 14 - transverse abdominal muscle
on - to the shoulder blade. The muscle starts from the occipital bone, the spinous processes of the VII cervical and all thoracic vertebrae; attached to the acromion and scapular spine. Function: the upper muscle bundles raise the scapula, the middle ones bring it closer to the spine, the lower ones lower it. With fixed shoulder blades and bilateral contraction, it throws the head and neck back. Innervation: accessory nerve, CII-CIV.2.
Latissimus dorsi muscle(M. latissimus dorsi) starts from the spinous processes of 5-6 lower thoracic vertebrae, from all lumbar vertebrae, the dorsal surface of the sacrum, from the iliac crest; attached to the crest of the small tubercle of the humerus. Function: rotates the humerus inward, lowers the raised arm, pulls the lowered arm back to the median plane. With fixed hands, it participates in the act of inhalation. Innervation: thoracic nerve, CVII-CVIII.3.
Large and small rhomboid muscles(mm.
rhomboideus major et minor) start from the spinous processes of the VI-VII cervical and 4 upper thoracic vertebrae; attached to the medial edge of the scapula. Function: bring the scapula closer to the spine and lift them up. Innervation: dorsal nerve of the scapula, CIV-CV.4. M
muscle that lifts the scapula(m.
levator scapulae), starts from the transverse processes of the 4 upper cervical vertebrae; attached to the upper corner of the scapula.Function: raises the scapula, tilts to the side when the scapula is fixed
cervical region spine. Innervation: dorsal nerve of the scapula, CIV-CV.5.
Serratus posterior superior(m.
serratus posterior superior) lies under the rhomboid muscle. It starts from the spinous processes of the two lower cervical and two upper thoracic vertebrae, goes down; attached to the II-V ribs. Function: raises the ribs. Innervation: intercostal nerves, ThI-ThIV.
6.
Serratus posterior inferior(m.
serratus posterior inferior) starts from the spinous processes of the two lower thoracic and two upper lumbar vertebrae; attached to 4 lower ribs. Function: lowers the ribs. Innervation: intercostal nerves, ThIX-ThXII.
Deep back muscles The deep muscles of the back include 2 isolated muscle tracts - medial and lateral, located in the bone-fibrous canal, in the grooves between the spinous and transverse processes of the vertebrae and the corners of the ribs. The medial tract is represented by short muscles that lie deep in the bone-fibrous canal; the lateral lies superficially and is formed by long muscles. In the back of the neck, on top of these two tracts, is located
belt muscle of the neck. Muscles of the medial tract:
transverse spinous(m.
transversospinal) And
interspinous muscles(mm.
interspinales). The transverse spinous muscle is located from the sacrum to the occipital bone, it includes semispinous, multifidus muscles and rotator muscles. Function: unbend the spine, when contracted on one side, tilt the spine and torso to the side, rotate the spine.
suboccipital muscles(mm.
suboccipitales): anterior, lateral, large and small
back muscles head, top And
inferior oblique muscles of the head, splenius head And
longus muscle heads. Function: unbend the head, rotate it together with the atlas around the odontoid process. Muscles of the lateral tract:
erector spinae muscle(m.
erector spinae), consists of the iliocostal, longissimus and spinous muscles. Function: straighten the back, lower the ribs and take part in maintaining balance. The innervation of the deep muscles of the back is carried out by the posterior branches of the cervical, thoracic and lumbar spinal nerves.
Fascia of the back There are 3 fascias in the back area:
superficial, vynaya, lumbar-thoracic.superficial fascia it is weakly expressed and is part of the common subcutaneous fascia.
thoracic fascia(fascia thoracolumbalis) consists of two sheets (plates) - superficial and deep (Fig. 55). The surface sheet covers the lower and upper dentate muscles, forms fascial cases for the latissimus dorsi muscle,
Rice. 55. Lumbo-thoracic fascia and its plates. Horizontal section, top view: 1 - deep plate of the lumbar-thoracic fascia; 2 - large lumbar muscle; 3 - transverse process of the lumbar vertebra; 4 - body of the lumbar vertebra; 5 - spinous process; 6 - muscle straightening the spine; 7 - superficial plate of the lumbar-thoracic fascia; 8 - the junction of the superficial and deep plates of the lumbar-thoracic fascia; 9 - square muscle of the lower back; 10 - external oblique muscle of the abdomen; 11 - internal oblique muscle of the abdomen; 12 - transverse abdominal muscle; 13 - left kidney; 14 - intra-abdominal fascia; 15 - peritoneal rhomboid and trapezius muscles. A deep sheet covers the muscle that straightens the spine. At the top, the surface sheet covers the belt and semispinalis muscles of the head and neck, where it is compacted, receiving the name
nuchal fascia(fascia nuchae).chest musclesBreast- part of the body, bounded at the top by a conditional line running from the jugular notch of the sternum, then along the collarbone to the acromioclavicular joint, VII cervical vertebra; below, it starts from the xiphoid process of the sternum, continues along the costal arch (X rib), then along the XI-XII ribs and ends at the XII thoracic vertebra.
chest muscles are divided into two groups:
chest muscles attached to the upper limb, And
own muscles chest
(autochthonous). The diaphragm, which separates the chest cavity from the abdominal cavity, is also considered here (Fig. 56, 57).
Rice. 56. Superficial and deep muscles of the chest and abdomen, front view: 1 - pectoralis major muscle (sternocostal part); 2 - pectoralis major muscle (clavicular part); 3 - trapezius muscle; 4 - sternocleidomastoid muscle; 5 - chest fascia (deep plate); 6 - small pectoral muscle; 7 - deltoid muscle; 8 - serratus anterior; 9 - external oblique muscles; 10 - rectus abdominis; 11 - transverse abdominal muscle; 12 - internal oblique muscle of the abdomen; 13 - pyramidal muscle
Rice. 57. Trunk muscles, right side view. The scapula is retracted posteriorly, the pectoralis major and minor, the external oblique muscle of the abdomen and the major
gluteal muscle removed; the gluteus medius muscle is cut and partially removed: 1 - lower twin muscle; 2 — an internal obturator muscle; 3 - upper twin muscle; 4 - piriformis muscle; 5 - small gluteal muscle; 6 - latissimus dorsi; 7 - serratus anterior; 8 - a large round muscle; 9 - subscapularis muscle; 10 - internal intercostal muscles; 11 - external intercostal muscles; 12 - internal oblique muscle of the abdomen; 13 - gluteus medius
Muscles of the chest attached to the upper limb 1.
pectoralis major muscle(m.
pectoralis major) consists of 3 parts: clavicle
(pars clavicularis), starting from the medial end of the clavicle; sternocostal
(pars sternocostalis)- from the sternum and cartilage of II-VII ribs; abdominal
(pars abdominalis)- from the wall of the vagina of the rectus abdominis muscle. The muscle is attached by a common tendon to the crest of the greater tubercle of the humerus. Between the edge of the clavicle and the edge of the deltoid muscle, a deltoid-pectoral groove is formed
(sul. deltoideopectoralis), which at the top passes into the triangle of the same name. Passes in the furrow
v. cephalica. Function: lowers the raised arm, pulls it forward, simultaneously rotates the humerus inward. With a fixed hand, it raises the ribs, thereby participating in the act of inhalation.
Innervation: medial and lateral pectoral nerves, CV-CVIII.2.
pectoralis minor muscle(m.
pectoralis minor) starts from III-V ribs; attached to the coracoid process of the scapula. Function: pulls the scapula down and medially, with a fixed scapula raises the ribs. Innervation: medial and lateral pectoral nerves, CV-CVIII.3.
subclavian muscle(m. subclavius) starts from the 1st rib; attached to
extremitas acromialis claviculae. Function: pulls the clavicle down, with a fixed clavicle, raises the 1st rib. Innervation: subclavian nerve, CV-CVI.4.
Serratus anterior(m.
serratus anterior) begins with teeth from 8-9 upper ribs; attached to the medial edge of the scapula and to its lower angle. Function: pulls the lower angle of the scapula forward and laterally, thereby raising the arm above the horizontal line; with a fixed scapula, it raises the ribs, participating in the act of inhalation. Innervation: long thoracic nerve, CV-CVIII.
own chest muscles 1.
External intercostal muscles(mm.
intercostales externi) are located in the intercostal spaces from the spine to the costal cartilages. They start from the lower edge of the overlying rib, go obliquely down and forward; attached to the upper edge of the underlying rib. Function: raise the ribs, participating in the act of inspiration. Innervation: intercostal nerves, Th1-ThXI.2.
Internal intercostal muscles(mm.
intercostales interni) lie under the outer ones and have the opposite direction of the course of muscle fibers, located from the sternum to the corners of the ribs. Function: lower the ribs, participating in the act of exhalation. Innervation: intercostal nerves, ThI-ThXI.3.
Subcostal muscles(mm. subcostales) unstable, located in the posterior chest on the inner surface of the ribs, outward from the corners. They begin and insert like the internal intercostal muscles, but are carried over one or two ribs.
Function: lower the ribs. Innervation: intercostal nerves, ThVIII-ThXI.4.
Transverse chest muscle(m. transversus thoracis) starts from the posterior surface of the sternum, attaches to the III-VI ribs. Function: lowers the ribs. Innervation: intercostal nerves, ThIII-ThVI.
Breast fascia Fascia is isolated on the chest:
superficial, thoracic, clavicular-thoracic, external intercostal And
intrathoracic. 1.
superficial fascia weakly expressed, forms a capsule for the mammary gland.2.
Thoracic fascia(fascia pectoralis) has 2 leaves: superficial and deep. They form a large vagina
chest muscle.3.
Clavicular-thoracic fascia(fascia clavipectoralis) forms the sheath of the subclavian and pectoralis minor muscles. A cellular subpectoral space is formed between the thoracic and clavicular-thoracic fascia. Below, at the lower edge of the pectoralis major muscle, the superficial and deep sheets of the pectoral fascia are connected, passing into the axillary fascia.4.
External intercostal fascia covers the external intercostal muscles.5.
Intrathoracic fascia(fascia endothoracica) lines the inner surface of the chest, passing to the diaphragm.
DiaphragmDiaphragm(diaphragma)- unpaired thin tendon-muscle plate of a domed shape. The diaphragm closes the lower aperture of the chest, separating the chest cavity from the abdominal cavity (Fig. 58). The diaphragm begins with muscle-tendon fibers from bone formations that limit the lower thoracic aperture
Rice. 58. Diaphragm, bottom view, from the side of the abdominal cavity: 1 - square muscle of the lower back; 2 - small lumbar muscle; 3 - large lumbar muscle; 4 - iliac fascia; 5 - transverse fascia; 6 - psoas major (partially removed); 7 - iliac muscle; 8 - transverse muscles; 9 - lateral arcuate ligament; 10 - medial arcuate ligament; 11 - lumbar part of the diaphragm; 12 - esophageal opening; 13 - opening of the inferior vena cava; 14 - tendon center
cells. Muscle fibers, heading up, go into a tendon stretch, which occupies a central position and is called the tendon center.
(centrum tendineum). In its right side there is an opening of the inferior vena cava
(for. vv. cavae). Depending on the place of discharge of the muscle fibers of the diaphragm, 3 parts are distinguished in it: lumbar, costal, sternal.
Lumbar(pars lumbalis) the most powerful, consists of two legs - right and left
(crus dextrum et sinistrum). At the level of the XII thoracic and I lumbar vertebrae, the right and left legs converge, limiting the aortic opening
(hiatus aorticus), through which the aorta and the thoracic lymphatic duct lying behind it pass. Then the legs partially cross again and, diverging again, form the esophageal opening.
(hiatus esophageus) for passage of the esophagus and vagus nerves. Between the muscle bundles of the legs themselves, a large splanchnic nerve and an unpaired vein pass on the right, and the same nerve and a semi-unpaired vein on the left.
Costal part(pars costalis) begins with teeth from the inner surface of the lower 6 ribs. Muscle fibers go vertically up and inward, wrap in an arcuate shape and end in the tendon center.
sternal part(pars sternalis) represents the smallest part of the diaphragm. It starts from the xiphoid process in two bundles that rise upward and end in the tendon center. The diaphragm from the side of the chest cavity is covered with intrathoracic fascia, from the side of the abdominal cavity - with intra-abdominal fascia. Serous membranes are adjacent to the fascia: from the side of the chest cavity - the diaphragmatic pleura, in the middle part of the diaphragm - the pericardium, from the side of the abdominal cavity - the parietal sheet of the peritoneum. Function: diaphragm - respiratory muscle. With its contraction, the dome flattens, descending by 1-3 cm, while the volume of the chest cavity increases. When relaxed, the diaphragm rises, the capacity of the chest decreases.
Innervation: phrenic nerve and intercostal nerves, CIII-CV.
Abdominal musclesStomach The part of the body located between the chest and the pelvis. From above, it is limited by the xiphoid process, costal arches and a line connecting the ends of the XII ribs with the spinous processes of the XII thoracic vertebrae; below - symphysis, upper branches of the pubic bones, iliac crests; behind - a line connecting the spinous processes of the lumbar vertebrae. Consider also
abdominal cavity and its walls (see "Abdomen and peritoneum"). There are two groups of abdominal muscles:
anterolateral, uniting rectus, pyramidal and wide muscles (external, internal oblique and transverse), and
back, submitted
square muscles lower back (Fig. 59, 60). In the midline, tendon sprains (aponeuroses) of the lateral broad abdominal muscles form a fibrous band called
white line(linea alba), which goes from the xiphoid process to the symphysis.
Rice. 59. Superficial muscles of the abdomen: 1 - aponeurosis of the external oblique muscle of the abdomen; 2 - the muscular part of the external oblique muscle of the abdomen; 3 - the latissimus dorsi muscle; 4 - serratus anterior; 5 - subcutaneous adipose tissue and superficial vessels; 6 - spermatic cord entering the inguinal canal
Rice. 60. Inguinal canal, front view. On the right side, the external and internal oblique muscles of the abdomen are cut and turned to the side. On the left side, the anterior wall of the sheath of the rectus abdominis was removed: 1 - inguinal canal (opened); 2 - spermatic cord; 3 - rectus abdominis; 3a - pyramidal muscle; 4 - deep ring of the inguinal canal; 5 - superficial ring of the inguinal canal; 6 - aponeurosis of the external oblique muscle of the abdomen; 7 - transverse fascia of the abdomen; 8 - internal oblique muscle of the abdomen; 9 - transverse abdominal muscle
Approximately in the middle of the white line there is
umbilical ring(anulus umbilicalis), covered with fibrous scar tissue and skin. Sometimes the umbilical ring serves as a site for the formation of umbilical hernias.
Anterolateral group of abdominal muscles 1.
rectus abdominis(m.
rectus abdominis) steam room, lies on the side of the white line of the abdomen in the tendon sheath. It starts from the V-VII ribs of the xiphoid process, goes down; attached to the pubic bone and symphysis. Intersected along its length by tendon bridges
(intersectiones tendineae), which in the amount of 3-4 go transversely.
Vagina rectus abdominis formed by aponeuroses of oblique and transverse muscles and has two plates - anterior and posterior. Upper 3/4
anterior plate The vaginas are formed by the aponeurosis of the external oblique muscle of the abdomen and the anterior leaflet of the aponeurosis of the internal oblique muscle,
rear- the posterior leaf of the aponeurosis of the internal oblique muscle and the aponeurosis of the transverse abdominal muscle. The anterior plate of the lower quarter of the vagina is formed in front by the aponeuroses of all 3 broad abdominal muscles, and the posterior plate is formed only by the transverse fascia.2.
Pyramidal muscle(m.
pyramidalis) steam room, starts from the pubic bone; attached to the white line of the abdomen.Function: the pyramidal muscle and rectus abdominis stretch the white line.3.
External oblique abdominal muscle(m.
obliquus externus abdominis) steam room, the widest of all abdominal muscles. It starts on the lateral surface of the chest from the 8 lower ribs. Muscle bundles go from top to bottom, outside inwards. At the outer edge of the rectus abdominis, the muscle fibers pass into a tendon stretch, forming the anterior plate of the aponeurosis of the rectus abdominis. It is attached to the outer lip of the iliac crest. The lower edge of the aponeurosis of the external oblique muscle of the abdomen is thrown between the anterior superior iliac spine and the pubic tubercle and is called the inguinal ligament
(lig. inguinale), stretched in the form of a gutter. The fibers of the inguinal ligament, going down and medially, diverge, forming two legs - medial and lateral, limiting the triangular gap. medial pedicle
(crus mediale) attached to the symphysis, lateral
(crus laterale)- to the pubic tubercle. The medial and lateral crura limit
superficial inguinal ring. in the ass
lower section, between the external oblique muscle of the abdomen in front and
latissimus dorsi back, formed
lumbar triangle (trigonum lumbale); from below it is limited by the iliac crest, the bottom is the internal oblique muscle of the abdomen. Lumbar hernias can exit through this triangle.
4.
Internal oblique abdominal muscle(m. obliquus internus abdominis) steam room, lies under the external oblique muscle of the abdomen. It starts from the lumbar-thoracic fascia and the lateral sections of 2/3 of the inguinal ligament. Muscle bundles go fan-shaped and are attached to the lower edges of the X, XI, XII ribs, forming an aponeurosis, which is involved in the formation of the sheath of the rectus abdominis muscle and the white line.5.
transverse abdominis muscle(m.
transverse abdominis) steam room, located deeper than the internal oblique muscle of the abdomen. It starts from the inner surface of the six lower ribs, the lumbar-thoracic fascia and the inner third of the inguinal ligament, forms an aponeurosis that forms the posterior plate of the sheath of the rectus abdominis muscle and the white line. Fibers are split off from the lower edge of the internal oblique and transverse abdominal muscles in the inguinal canal
muscle that lifts the testis(T.
cremaster), which, as part of the spermatic cord, exits through the superficial inguinal ring and reaches the testicle. Function: the muscles of the anterolateral group exert pressure on the insides, forming the so-called
abdominal Press(prelum abdominale). This pressure contributes to the emptying of internal organs, for example, during defecation, urination, childbirth, vomiting. In addition, the muscles flex the spine, bringing the chest closer to the pelvis. Simultaneous contraction of the oblique abdominal muscles causes the torso to turn to the sides, while the internal and opposite external oblique muscles turn in their direction. Lowering the ribs, the muscles contribute to the act of breathing. Innervation: intercostal, iliac-hypogastric and ilio-inguinal nerves, ThV-ThXII, LI-LII.
Posterior abdominal musclesSquare muscle of the lower back(m.
quadratus lumborum) steam room, starts from the iliac crest, from the transverse processes of 3-4 lower lumbar vertebrae; attached to the lower edge of the XII rib, the transverse processes of the II-V lumbar vertebrae and to the body of the XII vertebra.
Function: lowers the XII rib, flexes the lumbar spine with bilateral contraction, flexes the spine to the side with unilateral contraction. Innervation: lumbar plexus, ThXII, LI-LII.
inguinal canalinguinal canal(canalis inguinalis) gap through which men pass
spermatic cord, and in women
round ligament of the uterus. It is located in the lower part of the abdominal wall from top to bottom, from outside to inside, from back to front. Its length is 4.0-4.5 cm. There are 4 walls and 2 holes in the canal.
Front the wall is formed by the aponeurosis of the external oblique muscle of the abdomen,
rear- transverse fascia
upper- the lower edges of the internal oblique and transverse abdominal muscles, the lower - the groove of the inguinal ligament. The outer opening of the channel -
superficial inguinal ring(anulus inguinalis superficial)- formed by the legs of the aponeurosis of the external oblique muscle of the abdomen. inner hole -
deep inguinal ring(anulus inguinalis profundus)- is located on the back surface of the anterior wall of the abdomen in the form of a deepening of the transverse fascia of the abdomen. It corresponds to the lateral inguinal fossa, located outward from the lateral umbilical fold, in the thickness of which the lower hypogastric artery passes (see Fig. 60; Fig. 61).
Rice. 61. The relief of the inner surface of the anterior wall of the abdomen in its lower sections; rear view, from the side of the abdominal cavity: 1 - lateral inguinal fossa; 2 - lateral umbilical fossa; 3 - medial inguinal fossa; 4 - medial umbilical fold; 5 - median umbilical fold; 6 - supravesical fossa; 7 - lower epigastric artery and veins; 8 - lateral umbilical fold; 9 -
bladder; 10 - parietal peritoneum; 11 - vas deferens; 12 - deep inguinal ring
Fascia of the abdomen Each abdominal muscle is covered by its own fascia. In the area of the superficial inguinal ring, the fascia continues to the muscle that lifts the testicle, and is called
fascia cremasterica. From the inside, the transverse muscle is covered with the transverse fascia, which is part of
intra-abdominal fascia(fascia endoabdominalis).
In practical terms, the space located between the transverse fascia of the abdomen and the parietal sheet of the peritoneum, the so-called preperitoneal space, is very important.
(spatium praeperitonialis), which posteriorly passes into the retroperitoneal space
(spatium retroperitoniale).Questions for self-control 1. What groups of back muscles by origin and position do you know? Name these muscles.2. List the deep muscles of the medial tract of the back. What function do they perform?3. List the deep muscles of the lateral tract of the back. What function do they perform?4. What dorsal fasciae do you know? What do they cover?5. Name the muscles of the chest that attach to the upper limb. Where do they start and end, what are their functions?6. Where does your own chest muscles begin and end? What is their function?7. What fasciae of the chest do you know? What does each of the fasciae form (cover)? 8. Where does each part of the diaphragm begin and end?9. What abdominal muscle groups do you know? Name these muscles. 10. What are the walls of the inguinal canal formed by?
Trunk muscles (mm. trunci). The muscles of the trunk are divided into back muscles (musculi dorsi), chest muscles (musculi thoraeis) and abdominal muscles (musculi abdominis). The muscles of the back are divided into superficial and deep.
Superficial back muscles
Trapezius muscle (m. trapezius), has the shape of a trapezoid or rhombus.
It starts from the superior nuchal line, external occipital protuberance, nuchal ligament and spinous processes of the VII cervical and all thoracic vertebrae. It is attached to the upper edge of the acromial end of the clavicle, to the humeral process of the scapula and to the scapular spine.
Function: when the upper bundles are reduced, it raises the shoulder girdle and brings the scapula to the spine. When the lower beams are reduced, the shoulder girdle is lowered and the shoulder blades are brought to the spine. When the entire muscle is contracted, the shoulder blades come closer, with a fixed shoulder girdle, tilts the head back.
The latissimus dorsi muscle (m. latfssimus dorsi) has a triangular shape.
It starts from the spinous processes from VI to XII of the thoracic and all lumbar vertebrae, the sacrum, the iliac crest and four teeth from the four lower ribs. The fibers go up and laterally, covering the lower angle of the scapula. Attaches to the crest of the lesser tubercle of the humerus.
Function, pulls the arm back and inward, with the upper limbs fixed, draws the torso to them.
The large and small rhomboid muscles (m.m. rhomboidei major et minor) are located next to the trapezius muscle, have a diamond shape.
They start from the spinous processes of the VI-VII cervical (small) and I-IV thoracic (large) vertebrae. Attached to the medial edge of the scapula.
Function: when contracting, they raise and bring together the shoulder blades.
The muscle that lifts the scapula (m. Levator scapulae).
It starts from the transverse processes of the 4th upper cervical vertebrae and goes down. Attached to the medial edge of the scapula.
Function: raises the shoulder blade.
Serratus posterior superior (m. serratus posterior superior).
It starts from the spinous processes of the 2 lower cervical and 2 upper thoracic vertebrae, located under the rhomboid muscles. It is attached with 4 teeth to the ribs from II to V.
Function: raises the ribs when inhaling.
Serratus posterior inferior (m. serratus posterior inferior).
It starts from the spinous processes of the XI-XII thoracic and I-II lumbar vertebrae and the thoracolumbar fascia. Attached to the IX-XII ribs.
Function: lowers the ribs when exhaling.
Deep muscles of the back
Belt muscle of the head and neck (m splenius capitis et cervicis).
It starts from the spinous processes of 4 - 5 lower cervical and 6 upper thoracic vertebrae, goes up and laterally. It is attached: the head part of this muscle - to the upper nuchal line and to the mastoid process of the temporal bone, the cervical part - to the transverse processes of the P-Sh of the cervical vertebrae.
Function: when contracting on one side, the head turns towards the contracted muscle, with bilateral contraction, it unbends the head and neck.
The muscle that straightens the spine (m. erector spfnae).
It lies between the spinous and transverse processes, forming on each side the lateral and medial tracts. The lateral tract consists of long muscles located superficially. The medial tract is formed by short muscles located between the vertebrae.
Begins: lateral tract - from the sacrum, spinous processes of the lumbar vertebrae, iliac crest and thoracolumbar fascia. It goes up to the back of the head and is divided according to attachment into 3 parts: 1) the muscles attached to the ribs - the iliocostal muscle (m. iliocostalis), in which the lumbar, thoracic and cervical sections are distinguished; 2) muscles attached to the transverse processes of all thoracic, upper cervical vertebrae and to the mastoid process - the longest muscle (m. long (ssimus), intertransverse muscles (m.m. intertransversarii), located between the transverse processes of two adjacent vertebrae; 3) muscles attached to the spinous processes of the II-VIII thoracic and II-IV cervical vertebrae - the spinous muscle (m. spinalis).
The medial tract is formed by short muscle bundles arranged in three layers. The superficial layer is represented by semispinalis muscles (m.m. semispinalis), the fibers of which are thrown over 5-6 vertebrae. The middle layer is formed by multifidus muscles (m.m. multifidi), the bundles of which are thrown over 3-4 vertebrae. The deep layer is represented by rotator muscles (m.m. rotatores), the bundles of which are thrown over the 1st vertebra or directed to the adjacent vertebra. In the thoracic region, there are muscles that lift the ribs (m.m. levatores costarum). In the cervical and lumbar regions, between the spinous processes of adjacent vertebrae, there are interspinal muscles (m.m. interspinales). The deep muscles of the back of the neck include the suboccipital muscles (Fig. 70): the upper and lower oblique muscles of the head (m.m obliquus capitis superior et inferior), the large and small posterior rectus muscles of the head (m.m rectus capitis posterior major et minor).
Function: the deep muscles of the back together straighten the torso, unbend the spine, rotate it, raise the ribs, while contracting on one side, these same muscles tilt the spine and torso in the same direction. The suboccipital muscles unbend, tilt to the side and rotate the head.
Depending on the position in the body and for the convenience of studying, the muscles of the head, neck, torso, muscles of the upper and lower extremities(Table 4).
Muscles located in different areas of the human body not only perform different functions, but also have their own structural features. On the limbs, with their long bone levers, adapted for movement in space, grasping and holding various objects, the muscles are, as a rule, spindle-shaped, with a longitudinal or oblique arrangement of muscle fibers, and narrow and long tendons.
| Names of muscles | Names of muscles |
| Muscles of the head Chewing muscles Mimic muscles Neck muscles Superficial muscles of the neck Suprahyoid muscles Infrahyoid muscles Deep muscles of the neck Muscles of the trunk Muscles of the back Superficial muscles of the back Deep muscles of the back Suboccipital muscles Chest muscles Superficial muscles of the chest Deep muscles of the chest Abdominal muscles Muscles of the side walls of the abdomen Muscles of the anterior abdominal wall | Muscles of the perineum muscles of the pelvic diaphragm muscles of the urogenital diaphragm Muscles of the upper limb muscles of the shoulder girdle muscles of the free part of the upper limb muscles of the shoulder muscles of the forearm muscles of the hand Muscles of the lower limb muscles of the pelvic girdle muscles of the free lower limb muscles of the thigh muscles of the lower leg muscles of the foot |
In the region of the trunk, in the formation of its walls, ribbon-like, flat and wide muscles with wide flat tendons - aponeuroses participate. In the head region, the masticatory muscles are attached at one end to the only movable part of the skull - the lower jaw. The mimic muscles begin on the bones of the skull and attach to the skin. With the contraction of these muscles, the relief of the face changes - facial expressions are formed.
Muscles of the head. All the muscles of the head are divided into two groups: chewing and facial.
The masticatory muscles begin on the fixed parts of the skull and attach to the lower jaw, setting it in motion during chewing and articulation. Chewing muscles four couples. temporalis muscle
(the strongest) is attached to the coronoid process of the lower jaw, acts mainly on the front teeth - incisors, canines (biting muscle). Actually chewing(second strongest) and medial pterygoid muscle attached to the angle of the lower jaw from the outside and from the inside. These muscles elevate the lower jaw. The fourth muscle lateral pterygoid, oriented in the anteroposterior direction in the sagittal plane and will attach to the articular process of the mandible. This muscle, with a bilateral contraction, pushes the lower jaw forward, with a unilateral contraction, it turns the lower jaw in the opposite direction. Mimic muscles are grouped around the openings of the head (Fig. 33). Some muscles surround them, are located around the opening of the mouth, around the eye sockets, nostrils, ear openings. This constrictor muscles, sphincters. Other facial muscles are oriented radially with respect to these openings - these are expanding muscles. Starting on the bones of the skull and attaching to the skin of the face and scalp, the facial muscles, when contracted, displace parts of the skin, form folds, furrows, dimples on the skin, which changes the expression of the face - forms facial expressions. Mimic muscles are also involved in the articulation of speech.
Rice. 33. Muscles of the head and neck (side view):
1 - tendon helmet (supracranial aponeurosis), 2 - frontal abdomen of the occipital-frontal muscle, 3 - circular muscle of the eye, 4 - muscle that lifts the upper lip, 5 - muscle that raises the corner of the mouth, 6 - circular muscle of the mouth, 7 - large zygomatic muscle, 8 - muscle that lowers the lower lip, 9 - muscle that lowers the corner of the mouth, 10 - muscle of laughter, 11 - subcutaneous muscle of the neck, 12 - sternocleidomastoid muscle, 13 - trapezius muscle, 14 - posterior ear muscle, 15 - occipital belly of the occipital-frontal muscle, 16 - upper ear muscle.
Muscles of the body. The muscles of the neck provide mobility of the cervical spine and head, and also act on the hyoid bone, strengthen the position of the larynx, and participate in lowering the lower jaw. Under the skin of the anterior region of the neck is one of the facial muscles – subcutaneous muscle of the neck. Deeper and to the side lies sternocleidomastoid muscle, which, with bilateral contraction, throws its head back. In the anterior regions of the neck are hyoid muscles, which begin on the sternum and scapula and attach to the hyoid bone and cartilage of the larynx. Suprahyoid muscles located between the hyoid bone and the lower jaw. They form the floor of the oral cavity and are involved in lowering the lower jaw.
Deeply located prevertebral muscles of the neck begin on the cervical vertebrae, at the top they are attached to the base of the skull, and at the bottom - to the I and II ribs (scalene muscles) participating in respiratory movements.
Back muscles. The muscles of the back are located on the back of the body from the base of the skull at the top to the sacrum below. There are superficial and deep muscles of the back (Fig. 34).
TO superficial back muscles which begin on the spine, include thin and wide trapezius muscles(above), which attach to the bones of the shoulder girdle (scapula and collarbone), broadest back muscle,
ending at the humerus. Beneath these muscles lie rhomboid muscles, serratus posterior muscles And muscle that lifts the shoulder blade. The serratus muscles act on the ribs, participating in the act of breathing.
Deep back muscles are located under the superficial muscles directly near the spinal column and act on it as extensors. The largest - thick and powerful muscle, straightening the trunk(extensor of the back). In the neck area are belt muscles of the head And neck. Under the muscle that straightens the trunk, there are shorter muscles that act on the spinal column as its extensors and rotators. The deep muscles are suboccipital muscles, starting on the I and II cervical vertebrae and attaching to the occipital bone. They tilt and turn their heads.
Rice. 34. Back muscles: 1 - trapezius muscle, 2 –
splenius head, 3 –
large and small rhomboid muscles, 4 –
serratus posterior inferior muscle, 5 - lumbar-thoracic fascia, 6 –
latissimus dorsi.
chest muscles. The muscles of the chest are also divided into superficial and deep.
Superficial muscles of the chest (large And pectoralis minor, serratus anterior) begin on the zebras, sternum and are attached to the scapula, collarbone and humerus. They carry out the movements of the shoulder girdle and upper limb (Fig. 35).
Deep chest muscles located in the intercostal spaces in two layers. They raise and lower the ribs, participating in the act of breathing. WITH intercostal muscles functionally related diaphragm(abdominal septum), which separates the chest cavity from the abdominal cavity and is a respiratory muscle. The diagram starts from the spinal column, lower ribs and sternum, and in the middle has tendon center, on which the heart rests. The esophagus, aorta, inferior vena cava, and celiac nerves pass through the holes in the diaphragm.
Abdominal muscles. Distinguish between the abdominal muscles involved mainly in the formation of the anterior and lateral walls of the abdominal cavity, and the muscles that form its posterior wall. The lateral walls of the abdomen are formed by wide and flat oblique And transverse abdominal muscles, lying in three layers. Wide flat aponeuroses of these muscles form a vagina for rectus muscle. Along the midline, the aponeuroses grow together with the same aponeuroses of the muscles of the opposite side, forming a vertically oriented white line of the abdomen. Almost in the middle of it is umbilical ring. The anterior abdominal wall is formed by rectus abdominis. It is located vertically from the lower part of the sternum at the top to the pubic bone at the bottom. On the back wall of the abdomen are lumbar muscles. They begin on the lumbar vertebrae and attach to the femur, which they act as flexors.
The muscles that form the walls of the abdomen are united under the general name - abdominal muscles. Together with the diaphragm, they are involved in creating intra-abdominal pressure, which contributes to the fixation of the abdominal organs.
With an increase in intra-abdominal pressure in the anterior wall of the abdomen, hernias can form - protrusions under the skin of internal organs. Most often they appear at the umbilical ring, in the inguinal and femoral canals, the diaphragm.
inguinal canal paired. It is located in the inguinal region, in the anterior-lateral sections of the anterior abdominal wall. In men, the spermatic cord passes through this canal, and in women, the round ligament of the uterus. femoral canal located below, at the exit from the pelvic cavity to the thigh.
Rice. 35. Muscles of the chest and abdomen:
1 - pectoralis major muscle, 2 - axillary fossa, 3 - latissimus dorsi muscle, 4 - serratus anterior muscle, 5 - external oblique muscle of the abdomen, 6 - aponeurosis of the external oblique muscle of the abdomen, 7 - umbilical ring, 8 - white line, 9 - inguinal ligament, 10 - superficial inguinal ring, 11 - spermatic cord.
The muscles and fascia of the body are divided according to their location into suboccipital muscles, muscles of the back, chest, abdomen And perineum. The muscles of the body are paired and are located symmetrically - on the right and on the left. BODY MUSCLE DEVELOPMENT Skeletal muscles appear at the 4th week of embryonic development from myotomes. Myotome cells - myoblasts differentiate and turn into striated skeletal muscle fibers. The dorsal part of the myotomes, located next to the spinous processes of the vertebrae, gives rise to the muscles of the back; from the ventral part of the myotomes, the muscles of the neck, chest and abdomen are formed. The dorsal muscles are separated from the ventral longitudinally located connective tissue septum, which later turns into a fascia. The innervation of the dorsal and ventral muscles of the body is different: the dorsal muscles are innervated by the posterior branches of the spinal nerves, the ventral muscles by the anterior ones. Subsequently, a connective tissue septum grows into the myotomes, dividing them into superficial and deep layers. The deep layers of the myotomes of the back are transformed in the dorsal region into the short muscles of the spinal column. The superficial parts of the myotomes of the back merge over a certain number of myotomes and, splitting off from the deeper ones, give the superficial muscles of the back, for example, the multifidus and semispinalis muscles. The most superficial layer - the muscle that straightens the spine, is located along the
kamous spinous processes. Simultaneously with the development of the muscles of the back, the formation of a connective tissue cover - fascia. The most developed and well-defined
thoracic fascia. The formation of the ventral muscles of the trunk occurs differently. Ventral parts of myotomes in the chest area on
early stages embryogenesis are located next to the spinal column. Growing forward along with the rudiments of the ribs developing in their myosepts, they lie in the intercostal spaces, splitting into outer and inner layers. In the future, they form respectively
outdoor And
internal intercostal muscles. Parts of the myotomes located on the outer surface of the ribs form the serratus posterior muscles and the most
big muscle, passing from the chest to the anterolateral wall of the abdomen, -
external oblique muscle of the abdomen. Under this muscle, myotomes are divided into 2 layers: the more external one forms
internal oblique muscle of the abdomen, and the deep layer
transverse abdominal muscle. rudiments
rectus abdominis muscles initially located laterally. As the ribs grow anteriorly and the sternum forms, the rudiments of the rectus abdominis muscles move anteriorly and are located on the side of the white line of the abdomen. The diaphragm is formed from the IV-V cervical segments. The resulting muscular rudiments of the diaphragm in the neck region move in the caudal direction to the lower aperture of the chest, where, merging, they form a muscular-tendon plate that covers the lower aperture of the chest. In the cervical region of the body, the ventral parts of the myotomes, merging and separating into layers, form
scalene muscles. Similarly, the deep muscles of the neck are formed, located on the front surface of the spine. BACK MUSCLES
Back,dorsum,- back surface of the trunk and neck; at the top it includes a notch - the back surface of the neck and reaches the external occipital protrusion, from below it is limited by the lateral edges of the sacrum, coccyx and iliac crests, laterally - by the posterior axillary line.
The muscles of the back are divided into two groups by origin and position:
superficial, including the muscles of the shoulder girdle - truncopetal, and muscles attached to the ribs, and
deep, formed from the dorsal parts of myotomes, i.e. autochthonous. The superficial muscles of the back are separated from the deep ones by a well-defined lumbar-thoracic fascia (Fig. 53).
Rice. 53. Back muscles. On the left - the first surface layer, on the right - the second surface layer. 1 - external oblique muscle of the abdomen; 2 - lumbar-thoracic fascia; 3 - the latissimus dorsi muscle; 4 -
triceps shoulder 5 - large round muscle; 6 - infraspinatus fascia; 7 - deltoid muscle; 8 - trapezius muscle; 9 - spinous process of the protruding vertebra; 10, 13 - belt muscles of the head; 11 - sternocleidomastoid muscle; 12 - semispinalis muscle; 14 - the muscle that raises the scapula; 15 - supraspinatus muscle; 16 - rhomboid muscle; 17 - infraspinatus muscle; 18 - a small round muscle; 19 - deltoid muscle (cut); 20 - large round muscle; 21, 23 - long head of the triceps muscle of the shoulder; 22 - lateral head of the triceps muscle of the shoulder; 24 -
shoulder muscle; 25 - external intercostal muscle; 26 - lateral
intermuscular septum shoulder 27 - lateral epicondyle; 28 - XII rib; 29 - internal oblique muscle of the abdomen; 30 - brachioradialis muscle; 31 - serratus posterior inferior.
Superficial back muscles
1.
trapezius muscle,t. trapezius, has a triangular shape; its base faces the spinous processes of the vertebrae, and its apex faces the scapula. The muscle starts from the superior nuchal line, external occipital protrusion, nuchal ligament, spinous processes of the VII cervical and all thoracic vertebrae; attached to the acromial end of the clavicle, acromion and scapular spine. Function: the upper muscle bundles raise the scapula, the middle ones bring it closer to the spine, the lower ones lower it. With fixed shoulder blades and bilateral contraction, she throws her head and neck back.
Innervation: accessory nerve, CII-CIV.
2.
latissimus dorsi muscle,m. latissimus dorsi, starts from the spinous processes of the 5-6 lower thoracic, from all lumbar vertebrae, the dorsal surface of the sacrum, from the iliac crest and 3-4 lower ribs; attached to the crest of the small tubercle of the humerus. Function: rotates the humerus inward, lowers the raised arm, pulls the lowered arm back to the median plane. With fixed hands, it participates in the act of inhalation. Innervation: thoracic nerve, СVII-СVIII.
3.
Large and small rhomboid muscles,mm. rhomboidei major et minor, start from the spinous processes of the VI-VII cervical and 4 upper thoracic vertebrae; attached to the medial edge of the scapula. Function: bring the shoulder blades closer to the spine and lift them up. Innervation: dorsal nerve of the scapula,
4.
Muscle that lifts the scapulat. levator scapulae, starts from the transverse processes of the 4 upper cervical vertebrae; attached to the upper corner of the scapula. Function: raises the scapula, with a fixed scapula tilts the cervical spine to the side. Innervation: dorsal nerve of the scapula, CIV-CV.
5.
Serratus superior posterior,t. serratus posterior superior, lies under the rhomboid muscle. It starts from the spinous processes of the two lower cervical and two upper thoracic vertebrae, goes down; attached by 4 teeth from II to V ribs, laterally from their corners. Function: raises the ribs. Innervation: intercostal nerves, ThI-ThIV.
6. Serratus posterior inferior,t. serratus posterior inferior, starts from the lumbar-thoracic fascia, from the spinous processes of the two lower thoracic and two upper lumbar vertebrae; attached to the 4 lower ribs. Function: lowers the ribs. Innervation: intercostal nerves, ThIX-ThXII.
Deep back muscles
The deep muscles of the back include 2 isolated muscle tracts - medial and lateral, located in the bone-fibrous canal, in the grooves between the spinous and transverse processes of the vertebrae and the corners of the ribs. The medial tract is represented by short muscles that lie deep in the bone-fibrous canal; the lateral lies superficially and is formed by long muscles. In the back of the neck, on top of these two tracts, is located
belt muscle of the neck. Muscles of the medial tract:
transverse spinous muscle,t. transversospinalis, located from the sacrum to the occipital bone. It includes
semispinous, multifidus muscles And
rotator muscles. Function: unbend the spine, while contracting on one side, tilts the spine and torso to the side, rotates the spine. In the back of the neck are located
suboccipital muscles,mm. suboccipitales, anterior, lateral, large And
small posterior muscles of the head, upper And
inferior oblique muscles of the head, splenius head And
long muscle of the head. Function: unbend the head back, rotate it together with the atlas around the odontoid process. Muscles of the lateral tract:
muscle that straightens the spinet. erector spinae(comprises
iliocostal, longest And
spinous muscles), And
interspinous muscles,tt. interspinales. Function: straighten the back, lower the ribs and take part in maintaining balance. The innervation of the deep muscles of the back is carried out by the posterior branches of the cervical, thoracic and lumbar spinal nerves.
Fascia of the back
There are 3 fascias in the back area:
superficial, vynaya, lumbar-thoracic.superficial fascia it is weakly expressed and is part of the common subcutaneous fascia.
thoracic fascia,fascia thoracolumbalis, consists of two sheets - superficial and deep. The superficial sheet covers the lower and upper serratus muscles, forms fascial cases for the latissimus dorsi, rhomboid and trapezius muscles. At the outer edge of the muscle that straightens the spine, the superficial sheet connects with the deep one (starts from the transverse processes of the lumbar vertebrae) and forms a bone-fibrous sheath for this muscle. At the top, the surface sheet covers the belt and semispinalis muscles of the head and neck, where it is compacted, receiving the name
extrinsic fascia,fascia nuchae.
MUSCLES OF THE CHEST - a part of the body, limited at the top by a conditional line running from the jugular notch of the sternum, then along the collarbone to the acromioclavicular joint, the VII cervical vertebra; below, it starts from the xiphoid process of the sternum, continues along the costal arch to the cartilage of the X rib, then along the XI-XII ribs and ends at the XII thoracic vertebra.
chest muscles are divided into two groups:
chest muscles attached to the upper limb, And
own chest muscles(autochthonous), formed from the ventral parts of myotomes and having a metameric structure (Fig. 54). The diaphragm, which separates the chest cavity from the abdominal cavity, is also considered here.
Muscles of the chest attached to the upper limb
1. pectoralis major muscle,t. pectoralis major, consists of 3 parts:
clavicular, pars clavicularis, starting from the medial end of the clavicle;
sternocostal, pars sternocostalis, - from the sternum and cartilage II-VII ribs;
abdominal, pars abdominalis,- from the wall of the vagina of the rectus abdominis muscle. The muscle is attached by a common tendon to the crest of the greater tubercle of the humerus. Between the upper outer edge of the clavicle and the edge of the deltoid muscle, a deltoid-pectoral groove is formed,
sulcus deltoideopectoralis, which at the top passes into the eponymous
triangle. Passes in the furrow
v. cephalica. Function: lowers the raised arm, pulls it forward, simultaneously rotates the humerus inward. With a fixed hand, it raises the ribs, thereby participating in the act of inhalation.
Rice. 54. Muscles of the body; front view. On the right - superficial muscles, on the left - deep muscles. 1 - sheath of the rectus abdominis muscle; 2 - external oblique muscle of the abdomen; 3 - short head of the biceps muscle of the shoulder; 4 - shoulder muscle; 5 - long head of the biceps of the shoulder; 6 - serratus anterior; 7 - deltoid muscle; 8 - pectoralis major muscle; 9 - deltoid-thoracic groove; 10 - trachea; 11 - trapezius muscle; 12 - thyroid cartilage; 13 - sternocleidomastoid muscle; 14 - sternohyoid muscle; 15 - scapular-hyoid muscle; 16 - subclavian muscle; 17 - coracoid process; 18 - tendon of the short head of the biceps of the shoulder; 19 - small pectoral muscle; 20 - tendon of the long head of the biceps of the shoulder; 21 - internal intercostal muscle; 22 - coracobrachial muscle; 23 - serratus anterior; 24 - shoulder muscle; 25 - external intercostal muscle; 26 - rectus abdominis; 27 - internal oblique muscle of the abdomen.
Innervation: medial and lateral pectoral nerves, CV-CVIII
2.
pectoralis minor,m. pectorialis minor, starts from III-V ribs; attached to the coracoid process of the scapula. Function: pulls the scapula down and medially, with a fixed scapula raises the ribs. Innervation: medial and lateral pectoral nerves, CV-CVIII.
3.
subclavian muscle,t. subclavius, starts from the 1st rib; attached to
extremitas acromialis claviculae. Function: pulls the clavicle down, with a fixed clavicle, raises the 1st rib. Innervation: subclavian nerve, CV-CVI.
4.
serratus anterior,m. serratus anterior, begins with teeth from 8-9 upper ribs; attached to the medial edge of the scapula and to its lower angle. Function: pulls the lower angle of the scapula forward and laterally, thereby raising the arm above the horizontal line; when the scapula is fixed, it raises the ribs, participating in the act of inspiration. Innervation: long thoracic nerve, CV-CVIII.
own chest muscles
1.
external intercostal muscles,mm. intercostales externi, are located in the intercostal spaces from the spine to the costal cartilages. They start from the lower edge of the overlying rib, go obliquely down and forward; attached to the upper edge of the underlying rib. Between the cartilages of the ribs, instead of muscles, there is a fibrous plate - the external intercostal membrane,
membrana intercostalis externa. Function: raise the ribs, participating in the act of inspiration. Innervation: intercostal nerves, Th1-ThXI.
2.
internal intercostal muscles,mm. intercostales interni, lie under the outer ones and have the opposite direction of the course of the muscle fibers, are located along the length from the sternum to the corners of the ribs. Start from the upper edge of the ribs, go obliquely up and forward; attached to the lower edges of the overlying rib. The continuation of the muscles from the corners of the ribs to the spine is the internal intercostal membrane,
membrana intercostalis interna.
Function: lower the ribs, participating in the act of exhalation. Innervation: intercostal nerves, ThI-ThXI.
3.
rib muscles,mm. subcostales, unstable, located in the posterior chest on the inner surface of the ribs, outward from the corners. They begin and insert like internal intercostal muscles, but spread over one or two ribs. Function: lower the ribs. Innervation: intercostal nerves, ThVIII-ThXI.
4.
transverse chest muscle,m. transversus thoracis, starts from the posterior surface of the sternum, below the III and IV ribs and the xiphoid process; attached to the III-VI ribs. Function: lowers the ribs. Innervation: intercostal nerves, ThIII-ThVI.
Breast fascia
Fascia is isolated on the chest
superficial, thoracic, clavicular-thoracic, external intercostal And
intrathoracic.1.
superficial fascia weakly expressed, forms a capsule for the mammary gland.
2.
chest fascia,fascia pectoralis, has 2 leaves:
surface And
deep. They form the sheath of the pectoralis major muscle.
3.
Clavicular-thoracic fascia,fascia clavipectoralis, forms the sheath of the subclavian and pectoralis minor muscles. A cellular tissue is formed between the thoracic and clavicular-thoracic fascia.
subpectoral space. Below, at the lower edge of the pectoralis major muscle, the superficial and deep sheets of the pectoral fascia are connected, passing into the axillary fascia.
4.
External intercostal fascia covers the external intercostal muscles.
5.
intrathoracic fascia,fascia endothoracica, lines the inner surface of the chest, passing to the diaphragm.
Diaphragm
Diaphragm,
diaphragma, - unpaired thin tendon-muscle plate of a domed shape. The diaphragm closes the lower aperture of the chest, separating the chest cavity from the abdominal cavity (Fig. 55). The diaphragm begins with muscle-tendon fibers from bone formations that limit the lower aperture of the chest. Muscle fibers, heading up, go into tendon stretch, which occupies the central
Rice. 55. Diaphragm and muscles of the posterior wall of the abdomen (on the right, the square muscle of the lower back and partially the large and small lumbar muscles were removed). 1 - sternocostal triangle; 2 - costal part of the diaphragm; 3 - opening of the inferior vena cava; 4 - esophageal opening; 5 - aortic opening; 6 — the left leg of a diaphragm; 7 - lumbocostal triangle; 8 - square muscle of the lower back; 9 - small lumbar muscle; 10, 17 - large lumbar muscles; 11, 18 - iliac muscles; 12 - iliac fascia; 13 - subcutaneous fissure; 14 - wide fascia; 15 - external obturator muscle; 16 - iliopsoas muscle; 19 - lumbar-thoracic fascia (deep sheet); 20 — the right leg of a diaphragm; 21 - lateral arcuate ligament; 22 - medial arcuate ligament; 23 - lumbar part of the diaphragm; 24 - tendon center of the diaphragm; 25 - the sternal part of the diaphragm. The position is called the tendon center,
centrum tendineum. In its right side there is an opening of the inferior vena cava,
foramen venae cavae. Depending on the place of discharge of the muscle fibers of the diaphragm, 3 parts are distinguished in it:
lumbar, costal, sternum.lumbar,pars lumbalis, the most powerful, consists of two legs - right and left,
crus dextrum et sinistrum. Each leg in turn is divided into 3 legs:
medial, intermediate And
lateral. At the level of the XII thoracic and I lumbar vertebrae, the right and left legs converge, limiting the aortic opening,
hiatus aorticus, through which the aorta and the thoracic lymphatic duct lying behind it pass. Then the legs partially cross again and, diverging again, form the esophageal opening,
hiatus esophageus, for passage of the esophagus and vagus nerves. Between the medial and intermediate legs on the right pass
great splanchnic nerve And
unpaired vein, and on the left is the same
nerve And
semi-unpaired vein.
rib part,pars costalis, begins with teeth from the inner surface of the lower 6 ribs. Muscle fibers go vertically up and inward, wrap in an arcuate shape and end in the tendon center.
breast part,pars sternalis, represents the smallest part of the diaphragm. It starts from the xiphoid process in two bundles that rise upward and end in the tendon center. The diaphragm from the side of the chest cavity is covered with intrathoracic fascia, from the side of the abdominal cavity - with intra-abdominal fascia. Serous membranes are adjacent to the fascia: from the side of the chest cavity - the diaphragmatic pleura, in the middle part of the diaphragm - the pericardium, from the side of the abdominal cavity - the parietal sheet of the peritoneum. Function: diaphragm - respiratory muscle. With its contraction, the dome flattens, descending by 1-3 cm, while the volume of the chest cavity increases. When relaxed, the diaphragm rises, the capacity of the chest decreases. Innervation: phrenic nerve and intercostal nerves, CIII-CV. Abdominal muscles The abdomen is the part of the body located between the chest and the pelvis. From above, it is limited by the xiphoid process, the costal arches and the line connecting the ends of the XII ribs with the spinous processes of the XII thoracic vertebrae; below - symphysis, upper branches of the pubic bones, iliac crests; behind - a line connecting the spinous processes of the lumbar vertebrae. Consider
abdominal cavity and its walls (see "Abdomen and peritoneum"). There are two groups of abdominal muscles:
anterolateral, uniting the rectus, pyramidal and wide muscles (external, internal oblique and transverse), and
back, represented by the square muscles of the lower back (Fig. 56; see Fig. 55). In the midline, tendon stretching of the lateral broad abdominal muscles form a fibrous band called
white line,linea alba, which goes from the xiphoid process to the symphysis.
Approximately in the middle of the white line there is
umbilical ring,annulus umbilicalis, covered with fibrous scar tissue and skin. Sometimes the umbilical ring serves as a site for the formation of umbilical hernias.
Anterolateral group of abdominal muscles
1.
rectus abdominis,t. rectus abdominis, steam room, lies on the side of the white line of the abdomen in the tendon sheath. It starts from the V-VII ribs and the xiphoid process, goes down; attached to the pubic bone and symphysis. Crossed along its length by tendon bridges,
intersectiones tendineae, which in the amount of 3-4 go transversely, growing together with the anterior wall of the vagina (see Fig. 54).
Vagina rectus abdominis formed by aponeuroses of oblique and transverse muscles and has two plates - anterior and posterior. Upper 3/4
anterior plate The sheaths are formed by the aponeurosis of the external oblique muscle of the abdomen and the anterior leaflet of the aponeurosis of the internal oblique muscle,
rear- the posterior leaf of the aponeurosis of the internal oblique muscle and the aponeurosis of the transverse abdominal muscle. The anterior plate of the lower 1/4 of the vagina is formed in front by the aponeuroses of all 3 broad abdominal muscles, and the posterior plate is formed only by the transverse fascia. The transition of aponeuroses to the anterior plate of the vagina occurs along an arcuate line,
linea arcuata.2.
pyramidal muscle,t. pyramidalis, steam room, starts from the pubic bone; attached to the linea alba.
Rice. 56. inguinal canal; front view. On the right, the external and internal oblique muscles of the abdomen are cut and turned away, the walls of the deep (abdominal) inguinal ring of the inguinal canal are visible; on the left, the spermatic cord is cut off in the region of the deep inguinal ring. 1 - rectus abdominis; 2 - the vagina of the rectus abdominis muscle (the anterior plate is cut and turned away); 3 - deep inguinal ring; 4 - spermatic cord (cut); 5 - lateral leg of the aponeurosis of the external oblique muscle of the abdomen (turned away); 6 - aponeurotic sickle; 7 - the beginning of the aponeurosis of the external oblique muscle of the abdomen (inguinal ligament); 8 - medial leg of the aponeurosis of the external oblique, abdominal muscles (cut off and turned away); 9, 11 - spermatic cord; 10 - medial leg of the aponeurosis of the external oblique muscle of the abdomen; 12 - transverse fascia; 13 - aponeurosis of the external oblique muscle of the abdomen (cut and turned away); 14 - internal oblique muscle of the abdomen; 15 - external oblique muscle of the abdomen; 16 - transverse abdominal muscle.
73Function: Pyramidal muscle and rectus abdominis stretch the white line.
3.
External oblique muscle of the abdomen,t. obliquus externus abdominis, steam room, the widest of all abdominal muscles. It starts on the lateral surface of the chest from the 8 lower ribs with teeth between the anterior
serratus muscle and latissimus dorsi. Muscle bundles go from top to bottom, outside inwards. At the outer edge of the rectus abdominis, the muscle fibers pass into a tendon stretch, forming the anterior plate of the aponeurosis of the rectus abdominis. It is attached to the outer lip of the iliac crest (see Fig. 54). The lower edge of the aponeurosis of the external oblique muscle of the abdomen is thrown between the superior iliac spine and the pubic tubercle and is called the inguinal ligament,
ligamentum inguinale, stretched in the form of a gutter. The fibers of the inguinal ligament, going down and medially, diverge, forming two legs - medial and lateral, limiting the triangular gap. medial leg,
crus mediale, attached to the symphysis, lateral,
crus laterale, to the pubic tubercle. In the upper lateral section, the legs are reinforced with transverse interpeduncular fibers,
fibrae intercrurales. Part of the fibers of the lateral pedicle in the form of a curved ligament,
ligamentum reflexum, approaches the anterior wall of the sheath of the rectus abdominis muscle, the other part of the fibers wraps at the medial attachment of the inguinal ligament downward, to the crest of the pubic bone, forming a lacunar ligament,
ligamentum lacunar. The medial and lateral crura, together with the folded ligament and interpeduncular fibers, limit
superficial inguinal ring. In the posterior lower section, between the external oblique abdominal muscle in front and the latissimus dorsi muscle in the back, a lumbar triangle is formed,
trigonum lumbale; from below it is limited by the iliac crest, the bottom is the internal oblique muscle of the abdomen. Lumbar hernias can exit through this triangle.
4.
Internal oblique muscle of the abdomen,t. obliquus internus abdominis, steam room, lies under the external oblique muscle of the abdomen. It starts from the lumbar-thoracic fascia and the lateral sections of 2/3 of the inguinal ligament. The muscle bundles fan out and attach to the lower edges of the X, XI, XII ribs, forming an aponeurosis, which is involved in the formation of the sheath of the rectus abdominis muscle and the white line.
5.
transverse abdominal muscle,t. transversus abdominis, steam room, located deeper than the internal oblique muscle of the abdomen. It starts from the inner surface of the six lower ribs, the lumbothoracic fascia, the inner lip of the iliac crest and the inner third of the inguinal ligament, forms an aponeurosis that forms the posterior plate of the sheath of the rectus abdominis muscle and the white line. From the lower edge of the internal oblique and transverse abdominal muscles in the inguinal canal fibers are split off
muscle that lifts the testiclet.cremaster, which, as part of the spermatic cord, exits through the superficial inguinal ring and reaches the testicle. Function: the muscles of the anterolateral group exert pressure on the insides, forming the so-called abdominal press,
prelum abdominale. This pressure contributes to the emptying of internal organs, for example, during defecation, urination, childbirth, vomiting. In addition, the muscles flex the spine, bringing the chest closer to the pelvis. Simultaneous contraction of the oblique abdominal muscles causes the torso to turn to the sides, while the internal and opposite external oblique muscles turn in their direction. Lowering the ribs, the muscles contribute to the act of breathing. Innervation: intercostal, iliac-hypogastric and ilio-inguinal nerves, ThV-ThXII, LI-LII.
Posterior abdominal muscles
Square muscle of the lower back,t. quadratus lumborum, steam room, starts from the iliac crest, from the transverse processes of 3-4 lower lumbar vertebrae; attached to the lower edge of the XII rib, the transverse processes of the II-V lumbar vertebrae and to the body of the XII vertebra.
Function: lowers the XII rib, flexes the lumbar spine with bilateral contraction, flexes the spine to the side with unilateral contraction. Innervation: lumbar plexus, ThXII, LI-LII.
inguinal canal
inguinal canal,
canalis inguinalis, gap through which men pass
spermatic cord, and in women
round ligament of uterus(see fig. 56). It is located in the lower part of the abdominal wall from top to bottom, from outside to inside, from back to front. Its length is 4.0-4.5 cm. There are 4 walls and 2 holes in the canal.
front wall formed by the aponeurosis of the external oblique muscle of the abdomen
back - transverse fascia,
upper - the lower edges of the internal oblique and transverse
abdominal muscles,
lower - groove of the inguinal ligament.
The outer opening of the channel -superficial inguinal ring,annulus inguinalis superficialis, formed by the legs of the aponeurosis of the external oblique muscle of the abdomen, the curved ligament and interpeduncular fibers.
inner hole -deep inguinal ringannulus inguinalis profundus, located in the lower part of the posterior surface of the anterior abdominal wall, 1.5-2.0 cm above the middle of the inguinal ligament, in the form of a deepening of the transverse fascia of the abdomen. It corresponds to the lateral inguinal fossa, located outward from the lateral umbilical fold, in the thickness of which the inferior hypogastric artery passes.
Fascia of the abdomen
Each abdominal muscle is covered by its own fascia. In the region of the superficial inguinal ring, the fascia continues to the muscle that lifts the testicle, and is called
fascia cremasterica. From the inside, the transverse muscle is covered
transverse fascia, which is part
intra-abdominal fascia,fascia endoabdominalis. In practical terms, the space located between the transverse fascia of the abdomen and the parietal sheet of the peritoneum, the so-called subperitoneal space, is very important.
spatium praeperitonialis, which passes posteriorly into the retroperitoneal space,
spatium retroperitoniale.
QUESTIONS FOR SELF-CONTROL1. What groups of back muscles by origin and position do you know? Name these muscles.2. List the deep muscles of the medial tract of the back. What function do they perform?3. List the deep muscles of the lateral tract of the back. What function do they perform?4. What dorsal fasciae do you know? What do they cover?5. Name the muscles of the chest that attach to the upper limb. Where do they start and end, what are their functions?6. Where does your own chest muscles begin and end? What is their function?7. What fasciae of the chest do you know? What does each of the fasciae form (cover)? 8. Where does each part of the diaphragm begin and end?9. What abdominal muscle groups do you know? Name these muscles.10. What are the walls of the inguinal canal formed by?
