Anomalous origin and cervical course of the vertebral artery in the presence of a retroesophageal right subclavian artery.

The vertebral artery is usually described as the first branch of the subclavian artery, originating medial to the scalenus anterior muscle. During its cervical course, the vertebral artery presents a prevertebral segment and then enters the foramen transversarium of the sixth cervical vertebra. We describe a case of an unusual origin and course of the right vertebral artery in a cadaver specimen wherein the right vertebral artery originates from the right common carotid artery at the inferior border of the thyroid gland. In its cervical course the vertebral artery ascends outside and anteriorly to the foramen transversarium of vertebrae C VI to C III, and enters the foramen transversarium of the axis. In the same specimen, a retroesophageal right subclavian artery is also present. These vascular abnormalities are presented for physicians to keep in mind such variations during diagnostic investigation and surgical procedures of the neck.