Analysis of the regional anatomy of the retro-oesophageal right subclavian artery and surrounding structures.

Background: The retro-oesophageal right subclavian artery (RRSA) is a congenital anomalous branching of the arch of the aorta. Because its incidence is very low, it has not been fully understood how the RRSA develops during embryogenesis, and thus accumulation of observed findings in newly found cases is important to elucidate the aetiology of the RRSA.

Materials and methods: We encountered a case of the RRSA during the course of gross anatomy dissection for medical students.

Results: The main findings in the present observations are that (a) the RRSA arose from the right side wall of the arch of the aorta as its last branch; (b) the detected RRSA was directed to the right and upward between the oesophagus and vertebral column; (c) the right vertebral artery branched from the RRSA and entered the sixth cervical foramen transversarium; (d) the suprema intercostal artery branched from the costocervical trunk on both sides and its distal branches were distributed to the first and second intercostal spaces; and (e) both sides of bronchial arteries originated from the thoracic aorta.

Conclusions: The present study gives further information about the morphological details of the RRSA leading to better understanding of its developmental process.