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Straight abdominal muscle
Last reviewed: 23.04.2024
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The rectus abdominis muscle (rectus abdominis) is a flat, long ribbon-shaped muscle that is located on the side of the median line. Separated from the same muscle of the opposite side with a white belly line. The muscle begins with two tendon parts - on the pubic bone (between the pubic symphysis and the pubic tubercle) and pubic ligaments. Heading upward, the muscle widens noticeably and attaches to the anterior surface of the xiphoid process and the outer surface of the cartilages of VII, VI, and V ribs. Muscle bundles are interrupted by three or four transversely oriented tendon ligaments (intersectionis tendinei), tightly intertwined with the anterior plate of the vagina of the rectus abdominis muscle. With contraction of the abdominal muscles, the lintels in the lean people form transverse grooves that are clearly visible on the anterior abdominal wall, bounded from above and from below by protruding areas that correspond to the individual abdominal muscles of this muscle. The tendons of the rectus abdominis are the remains of connective tissue membranes (myosept) between the myotomes, from which this muscle developed. The first, most cranial located tendon jumper, is at the level of the cartilage of the VIII rib. The next, second, jumper is located in the middle of the distance between the first jumper and the navel; the third - at the level of the navel; the fourth is less common, weakly expressed, is located at the level of the arcuate line of the back wall of the vagina of the rectus abdominis.
The function of the rectus abdominis: with the strengthened spine and pelvic belt pulls the ribs down (lowers the rib cage), bends the spine (trunk), with a fixed chest lifts the pelvis.
Innervation of the rectus abdominis: intercostal nerves VI-XII (ThVI-ThXII), ilio-hypogastric nerve (ThXII-LI).
Blood supply to the rectus abdominis muscle: upper and lower epigastric arteries, posterior intercostal arteries.
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