| accessory hemiazygos vein | (n) a vein formed by the union of the 4th to 7th posterior intercostal veins; empties into the azygos vein, Syn. vena hemiazygos accessoria, accessory hemiazygous vein |
| azygos vein | (n) one of a system of veins that drain the thoracic and abdominal walls; arises as a continuation of the right ascending lumbar vein and terminates in the superior vena cava, Syn. azygous vein, vena azygos |