Abstract
This is a report of a case of an unusual origin of the right subclavian artery which was found in a 60-year-old Japanese man during dissection at the Showa University School of Medicine in 1994. The right subclavian artery arose from the posterosuperior wall of the aortic arch as its last branch. In addition to the abnormal origin of the right subclavian artery, the right vertebral artery arose from the right common carotid artery as the first branch and penetrated the transverse foramen of the 4th cervical vertebra. This artery travelled horizontally between the thoracic vertebral column and the esophagus toward the right side of the first thoracic vertebra. The right recurrent nerve was absent, but the right inferior laryngeal nerve was found to originate directly from the right vagus nerve. Other surrounding structures, such as the cervical sympathetic trunk and the thoracic duct, were normal. This case can be classified as type G according to the classification of Adachi, Williams, and Nakagawa and as figure 4 type according to the classification of Holzapfel. Moreover, this case belongs to type G' of the classification of Takemura et al. (1990) .
We believe the present case is the sixth case of this combined variation to be reported in Japanese.
