Cardiovascular system · Head and neck

Common carotid artery !

The common carotid artery runs up each side of the neck carrying blood to the head; it splits in two near the top of the voice box.

Official name: Right common carotid artery

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What it is

The main artery up each side of the neck, in the carotid sheath; its pulse is felt beside the larynx.

What it does

Carries blood to the head; it splits at the level of the upper larynx.

Key facts

Origin

Right: brachiocephalic trunk; left: aortic arch

Branches

No branches; divides at the upper border of the thyroid cartilage (C3–C4)

Supplies

Head and neck

Relations

Course

The right one begins behind the right sternoclavicular joint; the left one starts in the thorax from the aortic arch and enters the neck behind the left sternoclavicular joint. Both climb in the carotid sheath beside the trachea and larynx to the upper border of the thyroid cartilage

Lateral

Internal jugular vein, in the same sheath, with the vagus nerve in the groove behind and between them

Medial

Trachea and oesophagus below, larynx and pharynx above; the lobe of the thyroid gland overlaps it in front, and the recurrent laryngeal nerve runs in the groove between trachea and oesophagus

Behind

Sympathetic trunk, longus colli and longus capitis, and the transverse processes of the cervical vertebrae; at about C6 the inferior thyroid artery passes medially behind the sheath, near the middle cervical ganglion, and below C6 the vertebral artery lies deeper; low on the left, the thoracic duct arches behind the sheath

Superficial

Sternocleidomastoid, which overlaps it, and the infrahyoid muscles (sternohyoid, sternothyroid, and the omohyoid crossing at about C6); the ansa cervicalis lies on the front of the sheath

How to find it

With the person seated and the head turned slightly toward the side examined, the pulse is felt in the carotid triangle: medial to the front edge of the sternocleidomastoid at the level of the thyroid cartilage, pressing gently backwards toward the transverse processes. One side is examined at a time, and low in the neck rather than at the bifurcation, to avoid pressing on the carotid sinus.

Examination

• Pulse character: a slow-rising, small-volume pulse suggests aortic stenosis; a bounding, collapsing pulse suggests aortic regurgitation
• Auscultation over the bifurcation: a bruit can mean stenosis, but its absence does not exclude a tight narrowing, and a heart murmur can radiate here
• Carotid sinus massage (by clinicians, with ECG monitoring, one side at a time): it can slow some supraventricular tachycardias; a long pause or a marked fall in blood pressure suggests carotid sinus hypersensitivity

On imaging

Duplex ultrasound shows the common carotid, the carotid bulb and both branches, with wall thickness and plaque; CT or MR angiography maps the whole course from the aortic arch to the skull base.

Clinical notes

• Carotid sinus hypersensitivity: in older adults, turning the head, a tight collar or shaving can trigger a reflex slowing of the heart, a fall in blood pressure and fainting
• Central venous access: the internal jugular vein lies lateral to the palpable carotid; ultrasound guidance reduces accidental puncture of the artery
• A carotid body tumour (paraganglioma) at the bifurcation splays the internal and external carotid arteries apart (lyre sign) and moves side to side but not up and down
• Penetrating neck injuries are described by zones; zone II (cricoid cartilage to angle of the mandible) holds most of the common carotid and is the easiest to explore
• The omohyoid crossing divides it: below, it lies deep under the sternocleidomastoid and infrahyoid muscles; above, in the carotid triangle, it is superficial and is where it is usually exposed or tied

Anatomical variants

• A shared origin of the brachiocephalic trunk and the left common carotid artery (the so-called bovine arch) is the commonest aortic arch variant
• The bifurcation level varies: it can lie as high as the hyoid bone or below the thyroid cartilage, which matters for surgery and ultrasound

Development

The common carotid and the first part of the internal carotid come from the third pharyngeal arch arteries.

Memory aid

Carotid sheath contents: "I See 10 CC's in the IV" (Internal Carotid above, cranial nerve 10 = vagus, Common Carotid, Internal jugular Vein).

Related conditions

• Carotid artery stenosis
• Penetrating trauma (stab and gunshot wounds)

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Educational information, not medical advice. For any symptom, see a health professional.

Its names

Official Latin (TA2)

carotis communis dextra TA2 4181

Official Spanish (DeCS)

Arteria Carótida Común DeCS D017536

English (TA2)

Right common carotid artery

Also called

Carótida primitiva

Related

• Carotid sheath

Sources: Terminologia Anatomica (TA2); DeCS; Anatomy, Head and Neck, Anterior: Common Carotid Arteries; Anatomy, Head and Neck: Carotid Arteries; Tratado de anatomía humana (9.ª ed.), tomo II, Libro IV, sección 2 Arterias, caps. I-III (sistema de la arteria pulmonar; aorta y ramas del cayado hasta la carótida interna).

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Representative model, for educational purposes only.