Pharyngeal branches of inferior thyroid artery

The pharyngeal branches of the inferior thyroid artery are small arterial rami that arise from the inferior thyroid artery (ITA) as it courses medially toward the thyroid gland, and supply the inferior pharyngeal constrictor muscle and the adjacent pharyngeal and esophageal wall.

Origin and Course

The inferior thyroid artery most commonly arises from the thyrocervical trunk of the subclavian artery. It ascends along the anterior scalene muscle, then curves medially posterior to the carotid sheath to reach the inferior pole of the thyroid gland. Before entering the gland, the ITA typically divides into two or three terminal branches and also gives off several collateral branches — among them the pharyngeal branches, as well as esophageal, tracheal, and inferior laryngeal branches.

Territory of Supply

The pharyngeal branches ascend to supply the inferior constrictor muscle of the pharynx and the mucosa of the lower pharyngeal wall. Cadaveric dissection studies have confirmed that branches arising from the ITA (or from closely associated thyrocervical trunk vessels) supply the inferior pharyngeal constrictor and the adjacent esophagus. These pharyngeal rami anastomose with branches of the ascending pharyngeal artery (from the external carotid artery) and with pharyngeal branches of the superior thyroid artery, forming a rich vascular network around the hypopharynx.