Connection lost. Please refresh the page.
Get help How to study Login Register
Ready to learn?
Pick your favorite study tool

Common carotid artery

Recommended video: Arteries of the head and neck [18:08]
Major arteries of the head and neck.

The common carotid artery is a large elastic artery, which provides the main blood supply to the head and neck region. There is one common carotid artery on either side of the body and these arteries differ in their origin. The left common carotid artery arises from the aortic arch within the superior mediastinum, whilst the right common carotid artery arises from the brachiocephalic trunk posterior to the right sternoclavicular joint.

The common carotid artery ascends lateral to the trachea and esophagus within the deep cervical fascia, the carotid sheath, with the internal jugular vein and the vagus nerve. This article will discuss the anatomical relations and variations of the common carotid artery as well as briefly talking about its branches and specialised structures. This will be followed by any clinical pathology related to the common carotid artery.

Key facts about the common carotid artery
Origin Left common carotid artery: aortic arch
Right common carotid artery: brachiocephalic trunk
Main branches External carotid artery
Internal carotid artery
Supply area Structures of the head and neck (external carotid artery); forehead, nose, eyes and the ipsilateral cerebral hemisphere (internal carotid artery)
Clinical relations Carotid pulse, carotid sinus hypersensitivity, carotid artery stenosis
  1. Anatomical relations
    1. Within the lower neck
    2. Omohyoid muscle level
  2. Anatomical variations
  3. Branches
    1. External carotid artery
    2. Internal carotid artery
  4. Specialised structures
    1. Carotid sinus
    2. Carotid body
  5. Clinical notes
    1. Carotid pulse
    2. Carotid sinus hypersensitivity
    3. Carotid artery stenosis
  6. Sources
+ Show all

Anatomical relations

Within the lower neck

Relationships of the common carotid artery to other structures in the neck is important in clinical practice. Within the lower aspect of the neck, the two common carotid arteries are separated by the:

The common carotid artery ascends within the carotid sheath medial to the internal jugular vein and anterior to the vagus nerve.

Omohyoid muscle level

Inferior to the omohyoid muscle, the common carotid artery is covered by the:

​​At the level of the cricoid cartilage, the artery is crossed anterolaterally by the intermediate tendon of the omohyoid muscle. The artery then ascends more superficially and is only covered by the skin, fascia layers, the platysma and the sternocleidomastoid.

Superior to the omohyoid muscle it is crossed by the sternocleidomastoid branch of the superior thyroid artery. The anca cervicalis, a loop of nerves derived from the cervical plexus, is superficial to the common carotid artery within the carotid triangle.

Three veins cross the common carotid artery superficially. The superior thyroid vein crosses the artery at the upper aspect of the thyroid cartilage whilst the middle thyroid vein crosses at the level of the cricoid cartilage. The final vein, the anterior jugular, crosses the artery above the level of the clavicle.

The sympathetic trunk and ascending cervical branch of the inferior thyroid artery lie posterior to the common carotid artery. Deep to these structures are the longus colli, longus capitis and scalenus anterior muscles, which are attached to the transverse processes of C4-6. Below C6, the artery is located between the scalenus anterior and longus colli muscles and anterior to the sympathetic trunk, vertebral vessels, inferior thyroid artery and subclavian artery.

Carotid sheath dissected in a cadaver: Notice the position of the left external carotid artery; the artery is always anterior to the vagus nerve and medial to the internal jugular vein.

Anatomical variations

The left common carotid artery varies in its origin and can arise with the brachiocephalic artery. The right common carotid artery arises above the level of the sternoclavicular joint in 12% of cases.

Occasionally, the common carotid artery bifurcates at a higher level near the hyoid bone. More rarely, it bifurcates lower than usual at the level of the larynx. In very rare cases, the common carotid artery does not bifurcate, resulting in the absence of the external and internal carotid arteries. However, these may be replaced by arteries, which arise directly from the aorta. Apart from these two terminal branches, the common carotid artery usually gives off no other branches. However, it may occasionally give rise to superior thyroid, inferior thyroid, vertebral, occipital, ascending pharyngeal or superior laryngeal arteries.

Test your knowledge on the arteries of the head from a lateral view with this quiz.


At the level of the superior border of the laryngeal thyroid cartilage, the artery divides into two terminal branches, which are described below.

External carotid artery

The external carotid artery arises at the level of the intervertebral disc, between C3 and 4, and ascends slightly anteriorly before inclining posterolaterally. In the carotid triangle, it is anteromedial to the internal carotid artery. The external carotid gives off eight main branches, which supply regions of the head and neck.

Internal carotid artery

The internal carotid artery runs from its origin at the carotid bifurcation to the anterior perforated substance, where it bifurcates into the anterior and middle cerebral arteries at the Circle of Willis. It supplies the forehead, nose, eyes and the ipsilateral cerebral hemisphere.

Learn more about the internal and external carotid arteries with our articles.

Specialised structures

Near its bifurcation, the common carotid artery forms two specialised structures, which are described below.

Carotid sinus

The carotid sinus is a dilation of the base of the internal carotid artery, which is involved in relaying information about the arterial blood pressure to the hypothalamus. It is therefore referred to as a baroreceptor and is innervated by the carotid branch of the glossopharyngeal nerve.

Carotid body

The carotid body is an oval structure, located posterior to the carotid bifurcation, involved in relaying information about the arterial chemical composition to respiratory centres in the brainstem. Like the carotid sinus, it is innervated by the carotid branch of the glossopharyngeal nerve. The carotid body is surrounded by a fibrous capsule and consists of multiple lobules divided by septa. Within each lobule, there are two types of cells: glomus (type I) cells and sustenacular (type II) cells.The glomus cells are involved in storing peptides, such as neurotensin, and amines, such as adrenaline, noradrenaline and dopamine. The sustentacular cells separate the glomus cells from an extensive network of fenestrated sinusoids. The carotid body is a chemoreceptor stimulated by hypercapnia, hypoxia and increased hydrogen ion concentration (low pH).

In response to these changes, the carotid body changes the rate and volume of respiration via a reflex involving the respiratory centres in the brainstem.

Common carotid artery: want to learn more about it?

Our engaging videos, interactive quizzes, in-depth articles and HD atlas are here to get you top results faster.

What do you prefer to learn with?

“I would honestly say that Kenhub cut my study time in half.” – Read more.

Kim Bengochea Kim Bengochea, Regis University, Denver
© Unless stated otherwise, all content, including illustrations are exclusive property of Kenhub GmbH, and are protected by German and international copyright laws. All rights reserved.

Register now and grab your free ultimate anatomy study guide!