The superior thyroid artery is a paired blood vessel which lies in anterior aspect of neck. It mainly supplies the thyroid gland. It originates from the anterior side of external carotid at the level of the greater horns of the hyoid bone. Thus, it is the first branch given off by the external carotid just after this artery arises from the common carotid.
The superior thyroid artery first runs up some millimeters, then it curves medially and downwards, swerving to the upper pole of the lateral lobe of thyroid gland, where it ends up by dividing into an anterior and a posterior branch. In the gland, it anastomoses with branches of the inferior thyroid artery, which arises from the thyrocervical trunk.
Along its course, the superior thyroid artery gives off several branches: 1) the infrahyoid artery, which supplies oxygenated blood to the hyoid bone; 2) sternomastoid branch, which provides blood to the sternocleidomastoid muscle; 3) the superior laryngeal artery, which brings blood to the thyrohyoid muscle, the epiglottis and the mucous membrane of the larynx; 4) the cricothyroid branch, which supplies the cricothyroid muscle, forming an arched anastomosis with the contralateral branch.
Below, an schematic picture of the neck, exhibiting the external carotid and the superior thyroid artery
