Shield-shaped.Superior, a branch of the external carotid, distributed to the sternothyroid, sternohyoid, and omohyoid muscles and the thyroid body, and giving off the hyoid, sternomastoid, laryngeal, and cricothyroid branches.Inferior, a branch of the thyroid axis, passing beneath the great cervical vessels to be distributed to the lower part of the thyroid body, to the scalenus anticus, longus colli, inferior constrictor, and the infrahyoid muscles, and giving off the ascending cervical, inferior laryngeal, tracheal, and esophageal branches.n. The thyroid cartilage.n. The thyroid gland.n. A thyroid artery, vein, or nerve.