The thyroid region is primarily supplied by a major branch of which artery?

• A. Internal carotid artery
• B. External carotid artery
• C. Vertebral artery
• D. Common hepatic artery

Answer: (B)

Blood to the thyroid comes mainly from the superior thyroid artery, which branches off the external carotid artery. The external carotid supplies many neck structures, and the superior thyroid is its primary contributor to thyroid blood flow. The internal carotid artery mainly serves the brain, the vertebral artery supplies the posterior circulation, and the common hepatic artery goes to the liver. So, the major branch involved is from the external carotid artery.