A Riddle of Esophagography: Where Do the Descending Aorta and the Abdominal Aorta Run in Cases of the Right Aortic Arch? Report of two cases

Background: The right aortic arch is a rare anomaly of the aorta and is seen at 0.03~0.04% of the population. Case Presentation: We evaluated upper gastrointestinal series for 4,000 examinees between 2012 and 2016 and encountered two cases of the right aortic arch on esophagography. Case 1: Barium esophagography of a seventies-year-old Japanese female showed a wide anterior bowing of the upper thoracic esophagus, at the middle of which was there a small hump towards the vertebra. Case 2: Barium esophagography of a forties-year-old Japanese male showed at the first anterior bowing of the upper thoracic esophagus and then an anterior bowing of the lower thoracic esophagus. In the present cases, there adjacently are the upper thoracic vertebrae and upper thoracic esophagus, however, the right aortic arch runs across in between. Where do the descending aorta and the abdominal aorta run? We analyzed barium esophagography. In case 1, aright aortic arch runs at the upper bowing and the descending aorta soon returns from the right side of vertebra to the left side of the vertebra. In case 2, right aortic arch runs in case 1 as well, however, the descending aorta returns to the left above the diaphragm. It was suggested that the aorta in cases of right aortic arch be the shape of a right-side-left question mark. Conclusion: The descending aorta should be considered to run from the right side to the left side of the thoracic vertebrae.