accessory hemiazygous vein ac·ces·so·ryhemiazygousvein uncommon noun 1. a vein formed by the union of the 4th to 7th posterior intercostal veins; empties into the azygos vein Synonymsaccessory hemiazygos veinaccessory hemiazygous veinvena hemiazygos accessoria Related words Broader terms vein WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.
