Rosen Ryan D., Bordoni Bruno
Michigan State University
Foundation Don Carlo Gnocchi IRCCS
The thoracic aorta is subdivided into 3 sections: the ascending aorta, the aortic arch, and the descending aorta (see . Thoracic Aorta and the Aortic Arch, Computed Tomography Angiography). The ascending thoracic aorta arises from the left ventricle of the heart, anterior to the pulmonary artery, and rises to approximately the level of the fourth thoracic vertebra. The aorta then begins to travel posteriorly and to the left, where it is known as the arch of the aorta. The normal aortic arch gives rise to 3 vessels. The brachiocephalic trunk, also known as the innominate artery, is the first branch, bifurcating into the right subclavian and right common carotid artery. The brachiocephalic trunk is then followed by the left common carotid and subclavian arteries. The 'typical' pattern of aortic arch vessels occurs in approximately 70% of the population. Around the vertebral level of T4, the aorta continues as the descending thoracic aorta until it reaches the diaphragm. The ascending aorta develops as a component of the primitive heart tube. The primitive heart develops from 5 dilations: the truncus arteriosus, conus cordis, primitive ventricle, primitive atrium, and the sinus venosus. The truncus arteriosus forms the basis for developing the ascending aorta and pulmonary trunk, beginning during the fifth week of development. The truncus starts as a single outflow tract from the right and left ventricles but is eventually divided by the aorticopulmonary septum into separate vascular outflow channels. The truncal and conal ridges are invaded by neural crest cells, leading to spiraling that forms the aorticopulmonary septum. The aortic arch develops from multiple structures. The portion of the arch proximal to the brachiocephalic trunk arises directly from the aortic sac. The medial area of the arch, between the brachiocephalic trunk and the left common carotid artery, arises from the left fourth aortic arch. The portion of the arch distal to the left common carotid artery arises from the dorsal aorta. The descending aorta arises from the dorsal aorta. Early in development, the paired right and left dorsal aortae are confluent with the aortic sac. The right and left dorsal aortae later fuse along vertebral levels T4 to L4, forming a single, continuous dorsal aorta. The dorsal aorta ultimately gives rise to numerous vital branches, including intersegmental, splanchnic (visceral), and umbilical arteries. The dorsal aorta in this region is later referred to as the descending thoracic and abdominal aorta.
升主动脉、主动脉弓和降主动脉（见图。胸主动脉和主动脉弓，计算机断层扫描血管造影）。升胸主动脉发自心脏的左心室，位于肺动脉前方，上升至大约第四胸椎水平。然后主动脉开始向后向左走行，在那里它被称为主动脉弓。正常的主动脉弓发出三支血管。头臂干，也称为无名动脉，是第一分支，分为右锁骨下动脉和右颈总动脉。接着是左颈总动脉和左锁骨下动脉。主动脉弓血管的“典型”模式约见于70%的人群。在大约T4椎体水平，主动脉延续为降胸主动脉，直至到达膈肌。升主动脉作为原始心管的一个组成部分发育而来。原始心脏由五个膨大发育而成：动脉干、圆锥动脉干、原始心室、原始心房和静脉窦。动脉干是升主动脉和肺动脉干发育的基础，从发育的第五周开始。动脉干最初是左右心室的单一流出道，但最终被主动脉肺动脉隔分成单独的血管流出通道。神经嵴细胞侵入动脉干和圆锥嵴，导致形成主动脉肺动脉隔的螺旋状结构。主动脉弓由多个结构发育而来。头臂干近端的主动脉弓部分直接起源于主动脉囊。主动脉弓的内侧区域，在头臂干和左颈总动脉之间，起源于左第四主动脉弓。左颈总动脉远端的主动脉弓部分起源于背主动脉。降主动脉起源于背主动脉。在发育早期，成对的左右背主动脉与主动脉囊相连。左右背主动脉后来在T4至L4椎体水平融合，形成单一的连续背主动脉。背主动脉最终发出许多重要分支，包括节段间动脉、内脏或脏支动脉以及脐动脉。该区域的背主动脉后来被称为降胸主动脉和腹主动脉。
