Common carotid artery
The common carotid artery begins asymmetrically on both sides.
- The right common carotid artery arises after the brachiocephalic trunk divides into two branches, the other branch being the right subclavian artery (Read more!). The bifurcation is located approximately at the level of the right sternoclavicular joint.
- The left common carotid artery branches directly from the aortic arch (Read more!). The left common carotid artery usually is longer than the right one.
The common carotid arteries leave the thoracic cavity via the superior thoracic aperture. Both arteries ascend through the neck included in the common carotid sheath together with the following structures:
- Internal jugular vein - located lateral to the artery;
- Vagus nerve (CN X) - located posterior to the vein and artery;
- Ansa cervicalis - located anterior to the vein and artery.
Together with all the mentioned structures, the common carotid arteries on either side of the neck reach the carotid triangle of the neck. In the neck, the artery is located lateral to the trachea and esophagus.
As the common carotid arteries are magistral blood vessels, usually they don't give off any branches in the neck, but in the carotid triangle at the level of the upper margin of the thyroid cartilage, each common carotid divides into two arteries:
Carotid sinus and body
At its bifurcation, the common carotid artery is slightly dilated. This region is known as the carotid sinus, or carotid bulb, which contains baroreceptors that sense changes in the blood pressure and have an important role in regulating it.
The carotid body is another neurovascular structure. It is an oval sensory structure located behind the carotid bifurcation or between both terminal branches of the common carotid artery. It is in close relation with the carotid sinus.
The carotid body sometimes may appear as a group of separate nodules. The carotid body functions as an arterial chemoreceptor, and it mainly monitors the oxygen, carbon dioxide and pH levels in the arterial blood.