Subgross investigation of vessels originating from arcus aortae in guinea-pig (Cavia porcellus).

The vessels that originate from the aortic arch were studied in 16 adult guinea-pigs. Two major vessels, the left subclavian artery and the brachiocephalic trunk, were easily identified as they were branching off from the aortic arch. The brachiocephalic trunk, at first branched off to the left common carotid artery and continued as a common trunk, which was then divided into the right subclavian artery and the right common carotid artery. The left subclavian artery branched off to the following vessels: the costacervical trunk, the internal thoracic artery, a common trunk from which the dorsal scapular artery and the vertebral artery originated, and the superficial cervical artery. The right subclavian artery branched off to the bronchoesophageal artery (in five cadavers), the caudal thyroid artery (in three cadavers) and the tracheal artery (in three cadavers) in addition to the above vessels. There were two vertebral arteries branching off to the right subclavian artery in all dissected cadavers. However, only 10 cadavers had two vertebral arteries originating from the left subclavian artery. The first vertebral artery originated from the common trunk, whereas the second vertebral artery arose from the dorsal scapular artery. The second vertebral artery entered the foramen transversarium of the seventh cervical vertebrae and anastomosed with the first vertebral artery just before entering the foramen transversarium of the sixth cervical vertebrae.