The First Branch of the Aortic Arch is the Brachiocephalic Trunk
The brachiocephalic trunk (also called innominate artery) is the first branch of the aortic arch. 1
Normal Aortic Arch Anatomy
According to the American College of Cardiology Foundation/American Heart Association guidelines, the most common aortic arch branching pattern in humans consists of three major vessels arising separately from the arch in the following order:
- Brachiocephalic trunk (first branch)
- Left common carotid artery (second branch)
- Left subclavian artery (third branch)
This pattern is found in approximately 83% of the population 2. The brachiocephalic trunk subsequently divides into the right subclavian artery and right common carotid artery.
Anatomical Variations
While the brachiocephalic trunk is consistently the first branch in the standard configuration, it's important to note that anatomical variations do exist:
In about 15% of individuals, the left common carotid artery may arise from the brachiocephalic trunk rather than directly from the aortic arch, resulting in only two branches from the arch 2
Less common variations include direct origin of the left vertebral artery from the arch (0.79%) or other rare configurations 2
The term "bovine arch" is erroneously used to describe a common origin of the brachiocephalic trunk and left common carotid artery, but this is not actually the pattern found in cattle 1
Clinical Significance
Understanding the normal branching pattern of the aortic arch and its variations is critical for:
- Accurate interpretation of angiographic studies
- Planning and execution of vascular and cardiothoracic surgical procedures
- Management of aortic arch pathologies including aneurysms and dissections
The brachiocephalic trunk is particularly important as it supplies blood to the right arm, right side of the head and neck, and right side of the brain. Occlusive disease of this vessel can have severe ischemic consequences, especially in anatomical variants where multiple cerebral blood vessels originate from a single trunk 3.
Therefore, the correct answer is C) Brachiocephalic trunk.