The Internal Mammary (Internal Thoracic) artery originates from which artery?

• A. Subclavian artery
• B. Axillary artery
• C. Carotid artery
• D. Aorta

Answer: (A)

The artery in question is a direct branch of the subclavian artery. It originates from the first part of the subclavian and runs down the inside of the chest wall, giving off intercostal branches and continuing as the superior epigastric and musculophrenic arteries. This makes it distinct from the axillary artery, which is simply the continuation of the subclavian beyond the first rib; the carotid arteries are the major vessels supplying the head and neck; and although the subclavian on the left may arise from the aorta, the internal mammary artery itself does not originate from the aorta. This predictable origin is why the internal mammary artery is often used as a graft conduit in coronary bypass procedures.