Synonym: spermatic artery; internal spermatic artery; See: aorta (Branches of aorta)for illus.. thoracic artery. The internal ... Any of the nine pairs of arteries that originate from the dorsal side of the thoracic aorta and run horizontally between the ... A branch of the thoracic aorta, supplying blood to the diaphragm.. superior rectal artery. The terminal branch of the inferior ... A branch of the thoracic aorta or the upper intercostal arteries; usually there are two left bronchial arteries and one right ...