- Arcuate line (anterior abdominal wall)
Infobox Anatomy
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Latin = linea arcuata vaginae musculi recti abdominis
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Caption = Theinterfoveolar ligament , seen from in front. (Linea semicircularis labeled at center top.)
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The arcuate line of theabdomen (or linea semicircularis) is a horizontal line that demarcates the lower limit of the posterior layer of therectus sheath . It is also where theinferior epigastric vessels perforates the rectus abdominus.Superior to the arcuate line, the
internal oblique aponeurosis splits to envelope therectus abdominis muscle. Inferior to the arcuate line, the internal oblique andtransversus abdominis aponeuroses merge and pass superficial to therectus muscle .The arcuate line occurs about 1/3 of the distance from the
umbilicus to thepubic crest , but this varies from person to person. Above the arcuate line, therectus abdominis is surrounded by an anterior layer of therectus sheath and a posterior layer. The anterior layer is derived from theexternal oblique aponeurosis and the anterior laminina of theinternal oblique aponeurosis. The posterior layer is made up of the posterior lamina of the internal oblique aponeurosis and the tranverse abdominal aponeurosis. Inferior to the arcuate line, all three muscle aponeuroses make up the rectus sheath, that is now only anterior to the rectus abdominis and not posterior to it at all.Therefore, inferior to the arcuate line, the rectus abdominis rests directly on the
transversalis fascia .If one dissects the anterolateral
abdominal wall , the arcuate line may be difficult to see, since all the aponeuroses aretranslucent .External links
* - "Anterior Abdominal Wall: The Posterior Wall of the Rectus Sheath"
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* - "Anterior Abdominal Wall, Lower Part, Posterior View"
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