Common carotid artery

Last revised by Yoshi Yu on 15 Apr 2023

The common carotid arteries (CCA) are paired branchless arteries of the neck that supply blood to the head, face and neck. Each common carotid bifurcates into internal and external carotid arteries.

Although the left and right common carotid arteries follow the same course through the neck, their origin differs.

On the left, the common carotid arises directly from the aortic arch whereas, on the right, the origin is from the brachiocephalic trunk 10. The left common carotid artery can be thought of as having two distinct parts: thoracic and cervical. Since the right common carotid arises cranially, it only really has a cervical portion.

In the thoracic section, the left common carotid travels upwards through the superior mediastinum to the level of the left sternoclavicular joint where it is continuous with the cervical portion.

The cervical section of both common carotids follows a similar course. Each vessel passes obliquely upwards from behind the sternoclavicular joint to the level of the upper border of the thyroid cartilage, at approximately the C4 level 11. In the lower neck, the two common carotid arteries are separated from each other by the trachea. However, as the carotids ascend in the neck, they diverge becoming separated by the thyroid gland, the larynx and pharynx.

Each common carotid is contained within the carotid sheath which is derived from all three layers of the deep cervical fascia. In addition to containing the common carotid artery, the sheath also comprises the internal jugular vein and vagus nerve: the vein lies lateral to the artery, with the nerve in between the two.

The word carotid in the sense of a major neck artery was first recorded in English in 1667, and ultimately derives from the Greek word κάρος (karos) meaning stupor, as compression of the vessel induced "sleep" 8,9.

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Cases and figures

  • Figure 1: proximal aorta and its branches
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  • Figure 2: arteries of the neck
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  • Figure 3: common carotids and their relations
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  • Figure 4: mediastinum (Gray's illustration)
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  • Figure 5: development from the aortic arches (Gray's illustration)
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  • Figure 6: carotid artery development (Gray's illustration)
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  • Figure 7: vascular anatomy on CT (annotated scrollable images)
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