Three main branches typically originate from the upward convexity of the arch. In order from proximal to distal these are:
- (right) brachiocephalic artery (or innominate artery) which goes on to divided into the right subclavian and right common carotid arteries.
- left common carotid artery
- left subclavian artery
There are three common variations to the branching pattern:
- normal (as above) : seen in ~ 70% of patients.
- bovine arch : common origin of brachiocephalic and left common carotid artery - seen in approximately 15% of patients (more common in blacks)
- left common carotid has its origin from the brachiocephalic artery proper, rather than from a common trunk : seen in approximately 10% of patients (also more common in blacks)
Additionally there may be additional branches that arise directly from the arch. These include
- thyroidea ima artery, usually between the brachiocephalic and left common carotid
- left vertebral artery, usually between the left common carotid and the left subclavian arteries.
- rarely the right subclavian and right common carotid arise independently.
For congenital aortic anomalies see here.