From: eleanor hoppe <eleanor_hoppe@mac.com>
Date: April 11, 2008 11:12:36 PM EDT
To: eleanor hoppe <eleanor_hoppe@yahoo.com>
Subject: Transversus abdominis muscle - Wikipedia, the free encyclopedia
Transversus abdominis muscle
From Wikipedia, the free encyclopedia
(Redirected from Transversus abdominis)
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Transversus abdominis muscle |
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Muscles of the trunk. |
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The Transversus abdominis, Rectus abdominis, and Pyramidalis. |
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from the ribs and the iliac crest |
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inserts into the pubic tubercle via the conjoint tendon, also known as the falx inguinalis |
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The transversus abdominis muscle, also known as the transversalis muscle and transverse abdominal muscle, is a muscle layer of the anterior and lateral abdominal wall which is just deep to (layered below) the internal oblique muscle. It is a major muscle of the functional core of the human body.
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Structure
The transversus abdominis, so called for the direction of its fibers, is the innermost of the flat muscles of the abdomen, being placed immediately beneath the internal oblique muscle.
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Origin
It arises, as fleshy fibers, from the lateral third of the inguinal ligament, from the anterior three-fourths of the inner lip of the iliac crest, from the inner surfaces of the cartilages of the lower six ribs, interdigitating with the diaphragm, and from the lumbodorsal fascia.
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Insertion
The muscle ends in front in a broad aponeurosis, the lower fibers of which curve downward and medialward, and are inserted, together with those of the internal oblique muscle, into the crest of the pubis and pectineal line, forming the inguinal aponeurotic falx. In layperson's terminology, the muscle ends in the middle line of a person's abdomen.
Throughout the rest of its extent the aponeurosis passes horizontally to the middle line, and is inserted into the linea alba; its upper three-fourths lie behind the rectus muscle and blend with the posterior lamella of the aponeurosis of the internal oblique; its lower fourth is in front of the rectus abdominis.
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Layperson's description
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Innervation
The transversus abdominis is innervated by the lower intercostal nerves (thoracoabdominal, nerve root T7-T11), as well as the iliohypogastric nerve and the ilioinguinal nerve.
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Actions
The transversus abdominis (TVA) helps to compress the ribs and viscera, providing thoracic and pelvic stability. This is explained further here.
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Variations
It may be more or less fused with the Obliquus internus or absent. The spermatic cord may pierce its lower border. Slender muscle slips from the ileopectineal line to transversalis fascia, the aponeurosis of the Transversus abdominis or the outer end of the linea semicircularis and other slender slips are occasionally found. The nerves associated with the transverse abdominus are the intercostal, iliohypogastric, and the ilioinguinal.
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The muscle in movement and training
The most well known and effective method of strengthening it is the vacuum exercise, as well as engaging it during lifts. The transversus is the body's natural weight-lifting belt, stabilizing the spine and pelvis during lifting movements. Failure to engage the muscle at higher intensity lifts is dangerous and encourages injury. It acts as a girdle or corset in creating hoop tension around the midsection, tensing before contraction of the extremities.
Without a stable spine, the nervous system fails to recruit the muscles in extremities efficiently, and functional movements cannot be properly performed.[citation needed] Stabilization must then occur at the segmental level. The transversus abdominis and the segmental stabilizers of the spine are designed to work in tandem. This kind of lifting eventually overloads segmental stabilizers, and can result in massive lower back pain, early degeneration and many orthopedic problems.
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Additional images
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Diagram of a transverse section of the posterior abdominal wall, to show the disposition of the lumbodorsal fascia. |
Posterior surface of sternum and costal cartilages, showing Transversus thoracis. |
The interfoveolar ligament, seen from in front. |
Diagram of sheath of Rectus. |
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Diagram of a transverse section through the anterior abdomina wall, below the linea semicircularis. |
The abdominal inguinal ring. |
The abdominal aorta and its branches. |
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External links
This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.
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splenius (capitis, cervicis) - erector spinae (iliocostalis, longissimus, spinalis) - latissimus dorsi transversospinales: (semispinalis dorsi, semispinalis cervicis, semispinalis capitis, multifidus, rotatores) - interspinales - intertransversarii |
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rectus capitis posterior (major, minor) - obliquus capitis (inferior, superior) |
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intercostales (external, internal, innermost) - subcostales - transversus thoracis - levatores costarum - serratus posterior (inferior, superior) - diaphragm |
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anterior/lateral wall: obliques (external, internal) - transversus abdominis - rectus abdominis - pyramidalis posterior wall: quadratus lumborum - psoas major/psoas minor - iliacus |
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levator ani (iliococcygeus, pubococcygeus, puborectalis) - coccygeus |
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anal triangle: sphincter ani (externus, internus) superficial perineal pouch (superficial transverse perineal, bulbospongiosus, ischiocavernosus) deep perineal pouch (deep transverse perineal, sphincter urethrae membranaceae) |
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Categories: Muscles of the trunk
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