inferior thyroid vein

The inferior thyroid veins two, frequently three or four, in number, arise in the venous plexus on the thyroid gland, communicating with the middle and superior thyroid veins. They form a plexus in front of the trachea, behind the Sternothyreoidei. From this plexus, a left vein descends and joins the left innominate trunk, and a right vein passes obliquely downward and to the right across the innominate artery to open into the right innominate vein, just at its junction with the superior vena cava; sometimes the right and left veins open by a common trunk in the latter situation. These veins receive esophageal tracheal, and inferior laryngeal veins, and are provided with valves at their terminations in the innominate veins.