title: Pathogenesis of solitary right aortic arch: a mass effect hypothesis based on observations of serial human embryonic sections.
abstract: In general, solitary right aortic arch carries the left-sided ductus arteriosus communicating between the left subclavian and pulmonary arteries or the right-sided ductus connecting the descending aorta to the left pulmonary artery. Serial sections of fifteen 5- to 6-week-old embryos and ten 8- to 9-week-old fetuses suggested that the pathogenesis was unrelated to inversion due to dysfunction in gene cascades that control the systemic left/right axis. With inversion, conversely, the ductus or the sixth pharyngeal arch artery should connect to the right pulmonary artery. The disappearance of the right aortic arch started before the caudal migration of the aortic attachment of the ductus. Sympathetic nerve ganglia developed immediately posterior to both aortae, with a single embryonic specimen showing a large ganglion at the midline close to the union of the aortic arches. These ganglia may interfere with blood flow through the distal left arch, resulting in the ductus ending at the descending aorta behind the oesophagus. In another fetus examined, a midline shift of the ductus course resulted in the trachea curving posteriorly. Therefore, solitary right arch is likely to accompany abnormalities of the surrounding structures. The timing and site of the obstruction should be different between types: an almost midline obstruction near the aortic union needed for the development of the left-sided ductus and a distal obstruction near the left subclavian arterial origin needed for the development of the right-sided ductus. A mass effect of the sympathetic ganglia may explain the pathogenesis of any type of anomalous ductus arteriosus shown in previous reports of the solitary right arch.
authors.affiliation: 1Department of Anatomy,Histology and Embryology,Yanbian University Medical College,Yanji City,Jilin Province,China.
authors.forename: Zhe W
authors.initials: ZW
authors.lastname: Jin
authors.affiliation: 2Division of Internal Medicine,Iwamizawa Asuka Hospital,Iwamizawa,Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Yamada
authors.affiliation: 3Department of Anatomy, Faculty of Medicine,Chonbuk National University,Jeonju,Korea.
authors.forename: Ji H
authors.initials: JH
authors.lastname: Kim
authors.affiliation: 4Department of Anatomy and Embryology II, Faculty of Medicine,Complutense University,Madrid,Spain.
authors.forename: José F
authors.initials: JF
authors.lastname: Rodríguez-Vázquez
authors.affiliation: 2Division of Internal Medicine,Iwamizawa Asuka Hospital,Iwamizawa,Japan.
authors.forename: Gen
authors.initials: G
authors.lastname: Murakami
authors.affiliation: 2Division of Internal Medicine,Iwamizawa Asuka Hospital,Iwamizawa,Japan.
authors.forename: Keiji
authors.initials: K
authors.lastname: Arakawa
mesh_terms: D001013:Aorta, Thoracic / Q000002:abnormalities* / Q000196:embryology; D004373:Ductus Arteriosus / Q000196:embryology; D004374:Ductus Arteriosus, Patent / Q000175:diagnosis* / Q000196:embryology; D005333:Fetus; D006801:Humans; D054079:Vascular Malformations / Q000196:embryology*
keywords: Right aortic arch; ductus arteriosus; human embryo; inversion; pharyngeal arch arteries