Case of retroesophageal right subclavian artery, with special reference to the second intercostal artery, retroesophageal right vertebral artery, and thoracic duct.

We report a case of retroesophageal right subclavian artery identified in a 59-year-old Japanese female during routine dissection in Nagasaki University School of Medicine. This kind of variation is relatively rare; however, reports of such cases have accumulated. We paid attention to the intersegmental arteries and above all, the second intercostal artery. On the other hand, there have been reports of a retroesophageal right vertebral artery, although such cases are extremely rare. It is considered that both retroesophageal arteries are formed by similar mechanisms. In other words, the distal part of the right dorsal aorta remained in such cases. However, in the case of a retroesophageal right vertebral artery, there might be the possibility of intercostal arteries developing into the vertebral artery, and we discuss such points here.