Inferior thyroid veins Inferior thyroid veins The inferior thyroid veins appear two, frequently three or four, in number, and arise in the venous plexus on the thyroid gland, communicating with the middle and superior thyroid veins. While the superior and middle thyroid veins serve as direct tributaries to the internal jugular vein, the inferior thyroid veins drain directly to the brachiocephalic veins. They form a plexus in front of the trachea, behind the Sternothyreoidei. From this plexus, a left vein descends and joins the left brachiocephalic vein, and a right vein passes obliquely downward and to the right across the brachiocephalic artery to
Emissary veins Emissary veins The emissary veins connect the extracranial venous system with the intracranial venous sinuses. They connect the veins outside the cranium to the venous sinuses inside the cranium. They drain from the scalp, through the skull, into the larger meningeal veins and dural venous sinuses. Emissary veins have an important role in selective cooling of the head. They also serve as routes where infections are carried into the cranial cavity from the extracranial veins to the intracranial veins. There are several types of emissary veins including posterior condyloid, mastoid, occipital and parietal emissary vein. There are also emissary veins