Quick Facts
Origin: Aortic arch (left) or brachiocephalic trunk (right).
Course: Ascends in the superior mediastinum (left only) and in the neck.
Branches: External and internal carotid arteries.
Supplied Structures: Head and neck.
Origin
The left common carotid artery is the second branch arising from the aortic arch posterior to the manubrium of the sternum and posterolateral to the left of the brachiocephalic trunk. The right common carotid artery is a terminal branch of the brachiocephalic trunk.
Course
Since the left common carotid artery arises from the aortic arch, it contains both thoracic and cervical parts. It ascends in the superior mediastinum until it reaches the level of the left sternoclavicular joint. Here, it enters the neck.
The right common carotid artery arises from the brachiocephalic trunk at the level of the right sternoclavicular joint; thus, it has only cervical parts.
Once in the neck, the right and left common carotid arteries have a similar course. They ascend in the neck to the level of the third and fourth cervical vertebrae (the upper border of the thyroid cartilage of the larynx) and bifurcates into the external and internal carotid arteries (35% of individuals). The level of bifurcation varies significantly between individuals.
Branches
There are usually no pre-terminal branches of the common carotid arteries, however, sometimes, they may give rise to the vertebral, superior thyroid, superior laryngeal, ascending pharyngeal, inferior thyroid, or occipital arteries. In 27% of individuals, the left common carotid artery arises from the brachiocephalic trunk. Additionally, the brachiocephalic trunk may fail to form (~2.5%) and the right common carotid and right subclavian arteries arise directly from the aortic arch. In 1.2% of individuals, a right and left brachiocephalic trunk arises from the aortic arch (Tubbs, Shoja and Loukas, 2016). In this case, the left common carotid artery arises from the left brachiocephalic trunk.
Supplied Structures
The common carotid arteries provide arterial supply to the head and neck.
List of Clinical Correlates
- Atherosclerosis
- Carotid artery pulse
References
Tubbs, R. S., Shoja, M. M. and Loukas, M. (2016) Bergman's Comprehensive Encyclopedia of Human Anatomic Variation. Wiley.
Learn more about this topic from other Elsevier products
Left Common Carotid Artery
Zone 2 is defined as the aortic segment between the left common carotid artery and the left subclavian artery.
