Manor Preboards Module 1 Practice Test 2026 - Full Exam Prep

The thyroid gland is supplied mainly by two arteries. The superior thyroid artery, a branch of the external carotid artery, travels to the upper pole of the gland. The inferior thyroid artery, arising from the thyrocervical trunk of the subclavian artery, supplies the lower pole. Together, they form the rich vascular network needed for thyroid hormone production. There can also be an occasional thyroid ima artery, but the standard main sources are these two. The internal carotid and renal arteries do not directly nourish the thyroid, which is why the other options don’t fit as the primary supply.