Inferior thyroid vein
The inferior thyroid vein is a paired vein located in the lower neck. The left and right inferior thyroid veins arise at the inferior poles of the respective lobes of the thyroid gland. They have a short inferior course, each draining into the respective brachiocephalic vein.
The function of the inferior thyroid vein is to contribute to the venous drainage of the thyroid gland, along with the superior and middle thyroid veins. Moreover, it contributes to the draining of the cervical part of the esophagus, distal part of the larynx and the proximal part of the trachea as it communicates with the inferior laryngeal vein, esophageal and tracheal veins.
|Drains from||Thyroid venous plexus|
|Tributaries||Inferior laryngeal, esophageal and tracheal veins|
|Drains to||Brachiocephalic veins/ Superior vena cava|
|Drainage area||Thyroid gland, cervical part of esophagus|
This article will discuss the anatomy and function of the inferior thyroid vein.
Origin and course
The inferior thyroid vein arises from an anastomotic venous network between the superior and middle thyroid veins. Each inferior thyroid vein arises via several small branches, which leave the thyroid gland at the inferior border of its respective lobes. They then descend over the anterior surface of the trachea and the pretracheal fascia, where they anastomose and form the pretracheal venous plexus.
Each inferior thyroid vein leaves the pretracheal plexus at its inferior margin and continues the course towards the brachiocephalic veins. The left inferior thyroid vein drains into the left brachiocephalic vein, while the right inferior thyroid vein empties into the right brachiocephalic vein. At times, the inferior thyroid veins may join and drain directly into the superior vena cava or into the right brachiocephalic vein via a common trunk.
Tributaries and drainage area
The inferior thyroid veins contribute to the venous drainage of the thyroid gland. Moreover, via the pretracheal venous plexus, they collect the blood from the inferior laryngeal vein, esophageal veins and tracheal veins. Thus, the inferior thyroid veins also drain the cervical part of the esophagus, inferior part of the larynx and the cervical portion of the trachea.
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