American Board of Surgery Qualifying Exam (ABS QE) Practice Test

What is the first branch off the external carotid artery?

1. Inferior thyroid artery

2. Superior thyroid artery

3. Middle thyroid artery

4. Ophthalmic artery

The correct answer is: Superior thyroid artery

The first branch off the external carotid artery is the superior thyroid artery. This artery arises just below the level of the hyoid bone and supplies blood to the thyroid gland, as well as providing branches to the larynx and infrahyoid muscles. It plays a crucial role in vascularizing the thyroid and surrounding structures in the neck. Understanding the anatomy of the external carotid artery is vital, as it gives rise to several branches that supply various neck and head structures. The sequence of branches off the external carotid artery is important for surgical considerations, particularly in procedures involving the neck and thyroid. In contrast, other options such as the inferior thyroid artery generally branch off the thyrocervical trunk, which itself branches from the subclavian artery, making it unrelated to the external carotid artery. The middle thyroid artery is not commonly discussed as a primary branch off major arteries; it is less significant and can vary in its presence or origin. The ophthalmic artery is a branch of the internal carotid artery, not the external carotid artery, illustrating a different pathway in the vascularization of the head.