Rectus abdominis muscle: Difference between revisions
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{{Citations missing|date=June 2009}} |
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{{Muscle infobox |
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| Name = Rectus abdominis |
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| Latin = musculus rectus abdominis |
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| GraySubject = 118 |
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| GrayPage = 415 |
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| Image = Rectus abdominis.png |
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| Caption = The human rectus abdominis muscle. |
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| Insertion = [[Costal cartilage]] of [[ribs]] 5-7, [[xiphoid process]] of [[sternum]] |
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| Origin = [[pubis (bone)|pubis]] |
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| Blood = [[inferior epigastric artery]] |
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| Nerve = segmentally by [[thoraco-abdominal nerves]] (T7 to T12) |
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| Action = [[flexion]] of [[trunk]]/[[lumbar vertebrae]] |
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| Antagonist = [[Erector spinae]] |
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| DorlandsPre = m_22 |
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| DorlandsSuf = 12550436 |
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}} |
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The '''rectus abdominis muscle''' is a paired [[muscle]] running vertically on each side of the anterior wall of the human abdomen (and in some other animals). There are two parallel muscles, separated by a midline band of connective tissue called the [[Linea alba (abdomen)|linea alba]] (white line). It extends from the [[pubic symphysis]]/pubic crest inferiorly to the [[xiphisternum]]/xiphoid process and lower costal cartilages (5–7) superiorly. |
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--[[User:Chess371|Chess371]] ([[User talk:Chess371|talk]]) 14:12, 19 November 2009 (UTC)me |
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It is contained in the [[Rectus sheath]]. |
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The rectus is usually crossed by three fibrous bands linked by the [[tendinous inscriptions]]. While the "sixpack" is by far the most common configuration of the muscle bellies of the rectus, there exist rare anatomic variations which result in the appearance of eight ("eightpack"), ten, or—even rarer—asymmetrically arranged segments. All these variations are functionally equivalent. |
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==Function== |
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The rectus abdominis is a key [[posture|postural]] muscle. It is responsible for flexing the lumbar spine, as when doing a "[[Crunch (exercise)|crunch]]". The rectus abdominis assists with breathing and plays an important role in [[Respiration (physiology)|respiration]] in the event the patient is [[Dyspnea|short of breath]]. It also helps in keeping the internal organs intact and in creating intra-abdominal pressure, such as when exercising or lifting heavy weights, during forceful defecation or parturition. |
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==Blood supply== |
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The rectus abdominis has several sources of arterial blood supply. In reconstructive surgery terms, it is a Mathes and Nahai<ref>Mathes SJ, Nahai F. Classification of the vascular anatomy of muscles: experimental and clinical correlation. Plast Reconstr Surg. Feb 1981;67(2):177-87.</ref> Type III muscle with 2 dominant pedicles. First, the [[inferior epigastric artery]] and vein (or veins) run superiorly on the posterior surface of the rectus abdominis, enter the rectus fascia at the [[Arcuate line (anterior abdominal wall)|arcuate line]], and serve the lower part of the muscle. Second, the [[superior epigastric artery]], a terminal branch of the [[internal thoracic artery]], supplies blood to the upper portion. Finally, numerous small segmental contributions come from the lower 6 [[intercostal artery|intercostal arteries]] as well. |
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==Location== |
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[[Image:Sixpack germanuncut77 flickr.jpg|thumb|right|A man with extensively developed abdominal muscles, a good example of [[muscle hypertrophy|muscular hypertrophy]].]] |
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The Rectus abdominis is a long flat muscle, which extends along the whole length of the front of the abdomen, and is separated from its fellow of the opposite side by the [[linea alba (abdomen)|linea alba]]. |
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The muscle is inserted by three portions of unequal size into the cartilages of the fifth, sixth, and seventh [[ribs]]. |
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The upper portion, attached principally to the cartilage of the fifth rib, usually has some fibers of insertion into the anterior extremity of the rib itself. |
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Some fibers are occasionally connected with the [[costoxiphoid ligaments]], and the side of the [[xiphoid process]]. |
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==Damage== |
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{{Unreferenced section|date=October 2009}} |
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An abdominal muscle strain, also called a pulled abdominal muscle, is an injury to one of the muscles of the abdominal wall. A muscle strain occurs when the muscle is stretched too far. When this occurs the muscle fibers are torn. Most commonly, a strain causes microscopic tears within the muscle, but occassionally, in severe injuries, the muscle can rupture from its attachment. |
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{{clear}}<!-- Without this line pictures on the right would stack up especially on wide screens. Please do not remove this line. --> |
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==Animals== |
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{{Expand section|Animal examples needed|date=January 2009}} |
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[[Image:Feline Rectus Abdominus.jpg|thumb|right|A feline rectus abdominis muscle, from a common housecat. This specimen has some remaining [[fascia]] and also shows the external obliques.]] |
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The Rectus Abdominis is similar in most vertebrates. The most obvious difference between animal and human abdominal musculature is that in animals, there are a different number of tendinous intersections. |
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{{clear}}<!--Without this line pictures on the right would stack up especially on wide screens. Please do not remove this line. --> |
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==Additional images== |
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<gallery> |
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Image:Gray115.png|Anterior surface of sternum and costal cartilages |
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Image:Gray398.png|The interfoveolar ligament, seen from in front |
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Image:Gray399.png|Diagram of sheath of rectus |
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Image:Gray400.png|Diagram of a transverse section through the anterior abdomina wall, below the linea semicircularis |
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Image:Gray547.png|The relations of the femoral and abdominal inguinal rings, seen from within the abdomen. Right side |
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Image:Gray1038.png|Horizontal disposition of the peritoneum in the lower part of the abdomen |
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Image:Gray1097.png|Transverse section through the middle of the first lumbar vertebra, showing the relations of the pancreas |
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Image:Gray1215.png|The left side of the [[thorax]] |
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Image:Gray1219.png|Surface anatomy of the front of the thorax and abdomen |
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Image:Illu trunk muscles.jpg|Muscles of the trunk |
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</gallery> |
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==References== |
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{{Reflist}} |
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==External links== |
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* {{MuscleLoyola|reca}} |
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* {{GPnotebook|168165454}} |
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* {{SUNYAnatomyFigs|04|04|07}} – "Muscles of the anterior [[chest wall]] with the pectoralis major muscles removed." |
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* {{SUNYAnatomyLabs|18|01|01|15}} – "Thoracic Wall: The Anterior Thoracic Wall" |
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* {{SUNYAnatomyFigs|35|06|07}} – "Incision and reflection of the [[external abdominal oblique]] muscle." |
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* {{SUNYAnatomyFigs|35|07|01}} – "Incision and reflection of the [[internal abdominal oblique]] muscle." |
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* {{SUNYAnatomyLabs|35|10|01|00}} – "Anterior Abdominal Wall: The Rectus Abdominis Muscle" |
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* {{ViennaCrossSection|pembody/body12a}} |
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* {{eMedicineDictionary|Rectus+abdominis+muscle}} |
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* {{RocheLexicon|25466.180-1}} |
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{{Muscles of trunk}} |
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[[Category:Muscles of the torso]] |
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[[de:Musculus rectus abdominis]] |
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[[es:Recto mayor del abdomen]] |
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[[fr:Muscle grand droit]] |
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[[gl:Músculo recto maior do abdome]] |
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[[hr:Ravni trbušni mišić]] |
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[[it:Muscolo retto dell'addome]] |
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[[he:שריר הבטן הישר]] |
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[[la:Musculus rectus abdominis]] |
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[[nl:Musculus rectus abdominis]] |
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[[ja:腹直筋]] |
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[[pl:Mięsień prosty brzucha]] |
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[[pt:Músculo reto do abdome]] |
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[[sl:Prema trebušna mišica]] |
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[[fi:Suora vatsalihas]] |
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[[sv:Rectus abdominis]] |
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[[zh:腹直肌]] |
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