The anatomy of the human thyroid veins and its surgical application.

The present study was motivated by the importance of the thyroid veins in surgery in the anterolateral cervical region, particularly in tracheostomies, the need for information on modern diagnostic imaging techniques and the lack of specific publications on the subject. The research was performed on 30 adult human specimens by means of dissection and measurement. The superior thyroid vein was constant, single on both sides (83.3%), with its termination (87.1%) at the internal jugular vein (97.2%), either isolated (29.4%) or with other veins, mostly the lingual vein (52.1%), and was located between 1.0 and 2.5 cm below a plane that passes the upper margin of the hyoid bone. The medial thyroid vein, when present, was not constant (43.3%), was single (96.1%), terminated in the internal jugular vein and was located between 2.0 and 4.0 cm from the mid-sagittal line (84.6%). The inferior thyroid vein was constant (96.7%) and varied in number, with one (62.1%), two (27.6%) or even five occurring, and was formed by the confluence of two primary branches (78.6%) as a result of the abundance of anastomoses coming from the lower and medial parts of the gland. The number of terminations corresponded to the number of veins, at the level of the 5(th) to 8(th) rings in 36.9%, of the 9(th) to 10(th) rings in 34.8% and of the 11(th) to 14(th) rings in 28.3%, and occurred in the right brachiocephalic vein (26.1%), in the left brachiocephalic vein (60.9%) or in both veins (13.0%).