The superior thyroid artery arises, within the carotid triangle, from the front of the external carotid artery close to its origin. It runs downwards and forwards, under cover of the infrahyoid muscles, to the apex of the lobe of the thyroid gland, where it ends by breaking up into three terminal branches. In addition to muscular and terminal glandular branches, it has four named branches:

 

The infrahyoid artery is a small branch that runs along the lower body of the hyoid bone.

 

The inferior laryngeal artery is a larger vessel; associating itself with the internal laryngeal nerve, it pierces the thyrohyoid membrane, enters the pharynx, and descends to the larynx.

 

The sternomastoid branch is a small vessel which runs downwards and backwards across the carotid sheath.

 

The cricothyroid artery is a slender branch that arises under cover of the sternothyroid muscle. It runs medially across the cricothyroid muscle on to the cricothyroid membrane, where it anastomoses with its fellow.