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aorta[a-or´tah] (pl. aor´tae, aortas) (L.)
the great artery arising from the left ventricle, being the main trunk from which the systemic arterial system proceeds. It has four divisions: the ascending aorta, the aortic arch, the thoracic aorta, and the abdominal aorta. See Appendix of Arteries and see circulatory system.
overriding aorta a congenital anomaly occurring in tetralogy of Fallot, in which the aorta is displaced to the right so that it appears to arise from both ventricles and straddles the ventricular septal defect.
a congenitally malpositioned aorta the origin of which straddles the ventricular septum and so receives ejected blood from the right ventricle as well as from the left; it is found especially in tetralogy of Fallot.