rectus abdominis, m. rectus abdominis(see Fig. 309-311, 315, 325, 326), steam room, flat, refers to the long muscles of the abdomen; lies in the anterior abdominal wall on the sides of the white line of the abdomen, which stretches along the midline from the xiphoid process to the pubic fusion. The rectus abdominis muscle starts from the cartilages of the V-VII ribs and from the xiphoid process; heading down, narrows and attaches to the pubic bone in the gap between the pubic symphysis and the pubic tubercle. Across the muscle bundles of the rectus abdominis, interrupting them, there are 3-4 tendon bridges, interectiones tendineae. Two of them lie above the umbilical ring, one - at its level, and a poorly developed fourth bridge - sometimes below its level.

2. Pyramidal muscle , m. pyramidalis(see Fig. 309-311, 319, 323), steam room, has the shape of a triangle, its dimensions vary. It starts from the pubic bone, anterior to the place of attachment of the rectus abdominis muscle; its bundles, converging, rise upward and end at various levels of the lower divisions of the white line.
Both muscles, rectus and pyramidal, are enclosed in the vagina of the rectus abdominis muscle, vagina m. recti abdominis (see Fig. 310, 315, 319, 325), which is formed by aponeuroses broad muscles belly.
Function: are part of the abdominals, tilt the body anteriorly; the pyramidal muscles, in addition, stretch the white line of the abdomen.
innervation: nn. intercostales (ThV-ThXII), n. iliohypogastricus (ThXII, LI).
blood supply: rectus abdominis - aa. intercostalis, epigastricae superioret inferior; pyramidal muscle - aa. Cremasterica, epigastrica inferior.

Wide and long muscles the abdominal wall relate to the muscles of the body and determine the following movements: lowering the ribs, thus participating in the act of breathing; change the position of the spinal column; contraction of all muscles (except transverse) pulls chest down - spinal column leans forward; with unilateral contraction, lateral flexion of the spinal column occurs. With a unilateral contraction of the external oblique muscle, the spinal column turns in the direction opposite to the contracted muscle, and with a contraction of the internal oblique muscle, in its direction. The tone of the muscles of the abdominal wall and diaphragm contributes to the maintenance of intra-abdominal pressure, which is important in holding organs abdominal cavity in a certain position. With relaxation of the muscle tone of the abdominal wall (atony), a decrease in intra-abdominal pressure is observed and, as a result, the organs move downward (ptosis) under the influence of their own gravity, followed by a violation of their function. Due to the contraction of the muscles of the abdominal wall, the capacity of the abdominal cavity decreases, the organs are compressed, which helps to empty them (the act of defecation, urination, childbirth). On this basis, the muscles of the abdominal wall are called the abdominal press.

323. Inguinal canal, canalis inguinalis; front view.(On the right, the lower parts of the external oblique muscle of the abdomen are cut and retracted; on the left anterior wall rectus abdominis sheath opened and retracted.)

324. Inguinal canal, canalis inguinalis; front view.(Right outer and internal muscle the abdomen is cut and turned away, the walls of the deep inguinal ring, anulus inguinalis profundus, are visible; the spermatic cord is removed on the left, the superficial inguinal ring is visible, anulus inguinalis superftcialis.)

325. Inguinal canal, canalis inguinalis; front view.(On the right, the transverse fascia, fascia transversalis, and deep inguinal ring are visible.)

straight: right and left - begin in narrow, long bundles from the pubic crests and pubic symphysis, are attached to the outer surface of the cartilage of the Y-YII ribs with wide, ribbon-like stripes; along their course, the muscle bundles are interrupted by 3-4 tendon, transverse bridges, which fuse with the sheath of the rectus muscles;

rectus sheath formed from aponeurosesoblique And transverse muscles of the abdomen so that the anterior and posterior walls of it have an unequal structure: above the interspinous line, both walls of the vagina consist of one leaf of the aponeurosis of the external oblique muscle (anterior wall), one leaf of the aponeurosis of the transverse muscle (posterior wall), and half goes into each wall split aponeurosis of the internal oblique muscle; below the interspinous line, the anterior wall consists of three aponeuroses, and the posterior one is absent, and the rectus muscle is covered by the intra-abdominal fascia (its transverse part), which is clearly visible due to the arcuate line running along the lower edge of the posterior wall of the vagina of the rectus muscle;

white line, or rather, its aponeurosis, is formed when intersecting fibrous fibers of the aponeuroses of the oblique and transverse abdominal muscles grow along the anterior midline of the abdomen after they have formed the sheath of the rectus muscle.

Between the navel and the xiphoid process, the aponeurosis of the white line is wide, thin, often with small gaps between the fibers; between the navel and symphysis - it is narrow and thick; its similar structure is explained by the position of the rectus muscles, converging with narrow bellies to the pubis and diverging in wide ribbons to the costal cartilages.

The rectus muscles with a fixed spine and pelvis lower the chest, bend the torso, increase intra-abdominal pressure; with a fixed chest, raise the pelvis; they blood supply epigastric arteries: upper and lower, intercostal arteries, from the fifth to the 11th inclusive; innervated YI-XII intercostal nerves and iliac-hypogastric nerves from the lumbar plexus.

Pyramidal muscles start from the pubic crests and end in the aponeurosis of the white line below the navel; the muscles are short, lie in front of the straight lines - they stretch the aponeurosis of the white line.

Muscles of the lateral walls of the abdomen

External oblique muscle starts ledge-like from the outer surfaces of the lower 8 ribs interspersed with ledges of the anterior serratus muscle(from 5 lower ribs), attached to the outer lip of the iliac crest and the pubic tubercle - the lower edge of the muscular aponeurosis tucks inward and forms inguinal ligament, stretched between the anterior iliac spine and the pubic tubercle, where the aponeurosis diverges into the medial and lateral legs, limiting the external inguinal ring.

The anterior part of the muscular aponeurosis is involved in the formation of the sheath of the rectus muscle and the white line of the abdomen.

External oblique muscles with a strengthened pelvis lower the ribs and bend the spine with bilateral contraction, contribute to an increase in intra-abdominal pressure; with unilateral turn the torso; with a fixed chest, raise the pelvis.

Blood supply arteries: posterior intercostal, lateral thoracic, superficial surrounding ilium; innervated by intercostal, ilio-hypogastric, ilio-inguinal nerves.

Internal oblique muscle starts from the inguinal ligament (lateral two-thirds), intermediate line of the iliac crest, lumbar-thoracic fascia, runs from bottom to top and attaches to the cartilages of the last ribs. Ahead, the muscle passes into a wide aponeurosis, forming the sheath of the rectus muscle and the white line; at the bottom directs bundles of muscle fibers for the spermatic cord and cremasteric muscle of the testicle.

The muscle flexes the spine with a bilateral action, rotates the trunk with a unilateral contraction, lowers the ribs and raises the pelvis.

Blood supply arteries: posterior intercostal, lumbar, epigastric, muscular-diaphragmatic; innervated by the lower (6-12) intercostal, hypochondrium, iliac-hypogastric and iliac-inguinal nerves.

transverse muscle starts from inner surface 6 lower ribs between the teeth of the diaphragm, attaches to the inner lip of the iliac crest (anterior half), inguinal ligament (lateral third) and lumbothoracic fascia. Anteriorly, it passes into a wide aponeurosis, forming a semilunar line near and along the lateral edge of the rectus muscle and further into the sheath of this muscle and the white line of the abdomen.

The muscle increases intra-abdominal pressure, reducing the size of the abdominal cavity; shifts the ribs anteriorly; innervated And blood supply just like the internal oblique.

All three lateral muscles lie one on top of the other: on top - the external oblique, below it - the internal oblique, below - the transverse, forming a powerful muscle layer, surrounded and separated by the proper and transverse fascia of the abdomen.

The rectus abdominis muscle (m. rectus abdominis) (Fig. 90, 109, 110) tilts the body forward. It is part of the abdominal press and provides intra-abdominal pressure, due to which the internal organs are held in a certain position. In addition, she takes part in the acts of urination, defecation and childbirth. This flat long muscle is located in the anterior abdominal wall on the sides of the white line (linea alba), which runs from the xiphoid process of the sternum to the pubic fusion. The point of origin of the rectus abdominis muscle is located on the xiphoid process of the sternum and the cartilages of the V-VII ribs, and the attachment point is on the pubic bone between the pubic tubercle and the pubic symphysis (symphysis). The muscle bundles of the rectus abdominis muscle are interrupted by three to four transverse tendon bridges, two of which are located above the navel, the third at the level of the navel, and the fourth (poorly developed) below.

Rice. 109. Muscles of the anterior wall of the abdomen and pelvis: 1 - rectus abdominis;2 - iliac fascia;3 - iliopsoas muscle;4 - interfoveal ligament;5 - external iliac artery;6 - external iliac vein;7 - internal locking muscle;8 - muscle that raises the anus;9 - external locking muscle

The pyramidal muscle of the abdomen (m. pyramidalis) (Fig. 90, 110) stretches the white line of the abdomen. The muscle has a triangular shape, starts on the pubic bone, anterior to the insertion of the rectus abdominis muscle, and is attached at various levels of the lower white line.

Muscles of the lateral wall of the abdomen

The muscles of the lateral wall of the abdomen are broad abdominal muscles and are arranged in three layers.

The external oblique muscle of the abdomen (m. obliquus externus abdominis) forms the surface layer of the lateral wall of the abdomen. With a bilateral contraction (with a fixed position of the pelvis), the external oblique muscle pulls the chest and tilts the body forward, bending the spinal column, and with a unilateral contraction, it turns the body in the opposite direction. The muscle is wide and flat, is part of the abdominal press. The starting point is on the outer surface of the eight lower ribs. Muscle bundles are directed obliquely down and anteriorly (to the anterior section of the abdominal wall), pass into the aponeurosis (Fig. 104, 106). The attachment point is located on the upper part of the aponeurosis. The bundles of the aponeurosis, intertwining with the fibers of the aponeurosis of the muscles of the opposite side, form the white line of the abdomen. In this case, the lower bundles of the external oblique muscle are attached to the iliac crest, and the middle bundles of the aponeurosis form the inguinal ligament (lig. inguinale).

The internal oblique muscle of the abdomen (m. obliquus internus abdominis) (Fig. 101, 105, 110) is located under the external oblique muscle in the anterolateral part of the abdominal wall, that is, it forms the second layer of muscles of the lateral wall of the abdomen. With a unilateral contraction, the internal oblique muscle turns the trunk in its direction. The muscle is wide and flat, is the abdominal muscle. It originates from the iliac crest, inguinal ligament and thoracolumbar fascia. The muscle bundles diverge in a fan-like manner, heading along the oblique from below and from front to top and back. The posterior bundles are directed almost vertically and are attached to the outer surface of three or four lower ribs. The middle bundles, not reaching the lateral edge of the rectus abdominis muscle, pass into the aponeurosis, which forms the sheath of the rectus abdominis muscle. The lower bundles are directed horizontally, descend along the spermatic cord (funiculus spermaticus) and are part of the muscle that raises the testicle (m. cremaster) (Fig. 110).

The transverse abdominal muscle (m. transversus abdominis) (Fig. 103, 110) forms the deepest layer of the muscles of the lateral abdominal wall. The muscle is part of the abdominal press, flattens the abdominal wall and brings together the lower sections of the chest wall. At the top, the muscle starts from the inner surface of the cartilages of the six lower ribs, and below - from the iliac crest, inguinal ligament and thoracolumbar fascia. The muscle bundles are directed horizontally forward, not reaching the outer edge of the transverse muscle, they pass into the aponeurosis, which takes part in the formation of the white line of the abdomen. The bundles of the lower section of the transverse muscle, connecting with the lower bundles of the internal oblique muscle, participate in the formation of the muscle that lifts the testicle.

1. Rectus abdominis, m. rectus abdominis, steam room, flat, refers to the long muscles of the abdomen; lies in the anterior part of the abdominal wall on the sides of the white line of the abdomen, linea alba, which stretches along the midline from the processus xiphoideus to the pubic fusion. The rectus abdominis muscle starts from the cartilage of the V-VII ribs and from the processus xiphoideus; heading downward, it narrows and attaches to the pubic bone in the interval between the symphysis and tuberculum pubicum. Muscle bundles straight abdominal muscles interrupted by transversely running 3-4 tendon bridges, intersecliones tendineae. Two of them lie above the umbilicus, one at the level of the umbilicus, and a poorly developed fourth bridge sometimes below the navel.
2. Pyramidal muscle, m. pyramidalis, steam room, has a triangular shape, its dimensions vary. Starts from the pubic bone, anterior to the point of attachment of the straight abdominal muscles; its bundles, converging, rise upward and end at various levels of the lower divisions of the white line.

Both muscles, the rectus and pyramidal, are enclosed in the rectus sheath abdominal muscles, vagina m. recti abdominis, which is formed by the aponeuroses of the broad abdominal muscles. Action: they are part of the abdominal press, tilt the body forward; the pyramidal muscles, in addition, stretch the white line of the abdomen. Innervation: nn. intereostales, n. lumbalis (Th,-Thc; L,). Blood supply: rectus abdominis - aa. epigastricae superior et inferior, pyramidal muscle - aa. cremasterica, epigastrica inferior.

The wide and long muscles of the abdominal wall are the muscles of the trunk and cause the following movements: lowering ribs, thus participate in the act of breathing; change the position of the spinal column; contraction of all muscles (except the transverse one) pulls the chest downward - the spinal column leans forward; with unilateral contraction, lateral flexion of the spinal column occurs. With a unilateral contraction of the external oblique muscle, the spinal column rotates in the direction opposite to the contracted muscle, and with a contraction of the internal oblique muscle, the spinal column rotates in the direction corresponding to it.

The muscles of the abdominal wall and diaphragm with their tone, they maintain intra-abdominal pressure at a known height, which is important in keeping the abdominal organs in a certain position. With the relaxation of the tone of the muscles of the abdominal wall (atony), a decrease in intra-abdominal pressure is observed and, as a result, the organs move downwards (ptosis) under the influence of their own gravity, followed by a violation of their function. With the contraction of the muscles of the abdominal wall, the capacity of the abdominal cavity decreases, the organs are compressed, which helps to empty them (the act of defecation, urination, childbirth). On this basis, the muscles of the abdominal wall are called the abdominals. prelum abdominale.