|Artery: Arch of aorta, aortic arch|
|The thoracic aorta with its major branches. Note the large vessels sprouting from the arch|
|The aortic arch and its branches shown in situ.|
|Gray's||subject #142 547|
|Supplies||The entire body, with exception of the respiratory zone of the lung and the heart.|
|Vein||Combination of superior and inferior vena cava|
|Precursor||Fourth left pharyngeal arch artery|
The arch of the aorta or the transverse aortic arch (English pronunciation: //) is the part of the aorta that 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; it is then directed 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 the lower border of which it becomes continuous with the descending aorta.
It thus 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. The upper curvature has a region of higher pressure that forces blood flow to the upper regions of the body that are located above the heart (arms, neck, and head). The lower curvature of the arch has a lower pressure than the upper curvature, and this is where the ductus arteriosus is connected during the fetal stage, allowing the high pressure flow of blood from the right ventricle to mostly bypass the pulmonary vessels as they develop (they are still fluid filled).
Coming out of the heart, the thoracic aorta has a maximum dimension of 4 cm 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 descending aorta’s diameter shouldn’t exceed 25 mm.  
The arch of the Aorta lies within the mediastinum.
- OED 2nd edition, 1989, as /eɪ'ɔ:ɹtɪk/.
- Entry "aortic" in Merriam-Webster Online Dictionary.
- Acad Radiol. 2008 Jul;15(7):827-34.doi:10.1016/j.acra.2008.02.001. PMID: 18572117 [PubMed - 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 [PubMed - indexed for MEDLINE]
- wrongdiagnosis.com > Aortic knob Citing: Stedman's Medical Spellchecker, 2006 Lippincott Williams & Wilkins.
- Right Aortic Arch Anatomy Teaching Case from MedPix