Corpus: Superior thyroid artery

The superior thyroid artery is a branch of the external carotid artery that originates in the carotid triangle and supplies the thyroid gland with arterial blood.

The superior thyroid artery arises from the external carotid artery at approximately the level of the greater horn (cornu majus) of the hyoid bone. It is initially covered by the anterior edge of the sternocleidomastoid muscle. After a short upward and forward course, it runs directly to the thyroid gland. Within the gland, it anastomoses with branches of the inferior thyroid artery.

The superior laryngeal nerve is located medial to the superior thyroid artery.

• Infrahyoid branch: Supplies the hyoid bone.
• Sternocleidomastoid branch: Runs caudally and laterally to supply the sternocleidomastoid muscle.
• Superior laryngeal artery: Accompanies the internal laryngeal branch of the superior laryngeal nerve, running beneath the thyrohyoid muscle to supply the larynx.
• Cricothyroid branch: Supplies the cricoid cartilage.
• Glandular branches: Supply the thyroid gland.

Occasionally, the superior thyroid artery may branch off from the internal carotid artery instead of the external carotid artery

During a thyroidectomy, the superior thyroid artery must be ligated to prevent excessive bleeding. In some cases, it may be necessary to locate the vessel's origin at the external carotid artery. Ligation must be performed carefully, as the external laryngeal branch of the superior laryngeal nerve runs in close proximity, and inadvertent damage to this nerve can lead to complications.