The inferior thyroid veins appear two, frequently three or four, in number, and arise in the
venous plexus on the
thyroid gland
The thyroid, or thyroid gland, is an endocrine gland in vertebrates. In humans, it is a butterfly-shaped gland located in the neck below the Adam's apple. It consists of two connected lobes. The lower two thirds of the lobes are connected by ...
, 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 internal jugular vein is a paired jugular vein that collects blood from the brain and the superficial parts of the face and neck. This vein runs in the carotid sheath with the common carotid artery and vagus nerve.
It begins in the posteri ...
, the inferior thyroid veins drain directly to the
brachiocephalic veins.
The inferior thyroid veins form a
plexus in front of the
trachea
The trachea (: tracheae or tracheas), also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all animals' lungs. The trachea extends from ...
, behind the
sternothyroid muscle. From this plexus, the left vein descends and joins the
left brachiocephalic vein, and the right vein passes obliquely downward and to the right across the
brachiocephalic artery to open into the
right brachiocephalic vein, just at its junction with the
superior vena cava
The superior vena cava (SVC) is the superior of the two venae cavae, the great venous trunks that return deoxygenated blood from the systemic circulation to the right atrium of the heart. It is a large-diameter (24 mm) short length vei ...
; sometimes the right and left veins open by a common trunk in the latter situation.
Occasionally, a fourth thyroid vein—known as Kocher’s vein—may be present, arising between the middle and inferior thyroid veins and draining into the internal jugular vein.
The inferior thyroid veins receive
esophageal, tracheal, and
inferior laryngeal veins, and are provided with valves at their terminations in the
brachiocephalic veins.
Additional images
File:Gray505.png, The arch of the aorta, and its branches.
File:Gray562.png, The fascia and middle thyroid veins.
File:Gray1178.png, The thymus of a full-term fetus, exposed in situ.
File:Head ap anatomy.jpg, Head anatomy anterior view
References
Veins of the head and neck
Thyroid
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