ABSTRACT
In contrast to the arch type, the arch configuration refers to the usual or anomalous origin of the great vessels. In the usual configuration, the IA, left CCA, and the left subclavian artery (SCA) originate as the first, second, and third great vessels from the arch, respectively (65% of individuals) (Fig. 26.1). Anomalous configurations include common origin of the IA and left CCA (so-called bovine configuration, 25%) (Figs. 26.2 and 26.3), origin of the left CCA from the proximal IA (7%), separate origin of the left vertebral artery (VA) from the arch (0.5%), separate origin of the right SCA from the distal arch (arteria lusoria, 0.6%), and origin of the left CCA and left SCA from a left IA (1.0%). A true bovine configuration is extremely rare and consists of a single IA that trifurcates into a right SCA, a single CCA, and a left SCA; the single CCA divides into right and left CCA.
