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The aortic arch, arch of the aorta or the transverse aortic arch (〔''OED'' 2nd edition, 1989, as .〕〔(Entry "aortic" ) in ''(Merriam-Webster Online Dictionary )''.〕) is the part of the aorta between the ascending and descending aorta. The arch travels backward, so that it ultimately runs to the left of the trachea. ==Structure== It begins at the level of the upper border of the second sternocostal articulation of the right side, and runs at first upward, backward, and to the left in front of the trachea; then travels backward on the left side of the trachea and finally passes downward on the left side of the body of the fourth thoracic vertebra.〔 At this point the aortic arch continues as the descending aorta.〔 The aortic arch has three branches. The first, and largest, branch of the arch of the aorta is the brachiocephalic trunk, which is to the right and slightly anterior to the other two branches and originates behind the manubrium of the sternum. Next, the left common carotid artery originates from the aortic arch to the left of the brachiocephalic trunk, then ascends along the left side of the trachea and through the superior mediastinum. Finally, the left subclavian artery comes off of the aortic arch to the left of the left common carotid artery and ascends, with the left common carotid, through the superior mediastinum and along the left side of the trachea. The arch of the aorta forms two curvatures: one with its convexity upward, the other with its convexity forward and to the left. Its upper border is usually about 2.5 cm. below the superior border to the manubrium sterni. Blood flows from the upper curvature to the upper regions of the body, located above the heart - namely the arms, neck, and head. Coming out of the heart, the thoracic aorta has a maximum dimension of 40 mm at the root. By the time it becomes the ascending aorta, the diameter should be < 35–38 mm, and 30 mm at the arch. The diameter of the descending aorta should not exceed 25 mm.〔Acad Radiol. 2008 Jul;15(7):827-34.doi:10.1016/j.acra.2008.02.001. PMID 18572117 (- indexed for MEDLINE ) PMCID: PMC2577848〕〔JACC Cardiovasc Imaging. 2008 Mar;1(2):200-9. doi: 10.1016/j.jcmg.2007.11.005. Wolak A, Gransar H, Thomson LE, Friedman JD, Hachamovitch R, Gutstein A, Shaw LJ, Polk D, Wong ND, Saouaf R, Hayes SW, Rozanski A, Slomka PJ, Germano G, Berman DS. PMID 19356429 (- indexed for MEDLINE )〕 The arch of the Aorta lies within the mediastinum. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Aortic arch」の詳細全文を読む スポンサード リンク
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