The vertebral and internal mammary arteries are branches of which artery?

The vertebral and internal mammary arteries both branch off from the subclavian artery.

The vertebral artery arises from the first part of the subclavian artery and travels upward to supply the posterior part of the brain and the spinal cord. The internal mammary artery, also known as the internal thoracic artery, originates from the subclavian artery as well and descends along the inner surface of the ribcage to supply the anterior chest wall and breasts.

This understanding of vascular anatomy highlights the crucial role of the subclavian artery in providing blood supply to upper body structures, including the vertebral column and thoracic area, making it the correct answer to the question.