Vena hemizygous is a large unpaired vein situated on the left side of the roof of thoracic cavity.
It arises from the first lumbar vein receives radicles from psoas muscles, runs forwards and downwards to the level of the 8th dorsal vertebra, partly in contact with the bodies of the vertebrae and partly in contact with the upper face of the thoracic aorta, runs on the left dorsal face, passes downwards across the left of the aortic arch under the vagus and cardiac nerves passes obliquely downwards and backwards over the left auricle and joins the cardiac vein.
It receives veins from the vertebrae, diaphragm, and intercostal veins excepting first three on the left and the first six on the right.
