🪴 GoDeep
Search
← University Challenge
Portrait of Carotid artery

Anatomy · Heart & blood vessels

Carotid artery

Main arterial supply to the head and neck

Neck · carotid sheath

The common carotid arteries run up either side of the neck within the carotid sheath. The right arises from the brachiocephalic trunk and the left directly from the aortic arch. Each divides at about the upper border of the thyroid cartilage (C3–C4) into the internal carotid artery, which supplies the brain and eye, and the external carotid artery, which supplies the face, scalp and neck.

How to spot them

  • ▸Runs beside the trachea and larynx, deep to sternocleidomastoid, in the carotid sheath with the internal jugular vein and vagus nerve
  • ▸Pulsation felt in the neck at the level of the thyroid cartilage, just in front of sternocleidomastoid
  • ▸Divides in the carotid triangle into internal (no branches in the neck) and external (many branches)
  • ▸The swelling at the bifurcation is the carotid sinus, with the carotid body beside it

What to know

A pulse is felt in the neck, beside the larynx and in front of the sternocleidomastoid muscle

Carotid artery — the carotid pulse.

Its name comes from a Greek word meaning 'to stupefy', because pressure on it was thought to cause drowsiness

Carotid artery — Greek karoun.

Divides at the upper border of the thyroid cartilage into an internal and an external branch

Carotid artery — the bifurcation at C3–C4.

At its division lie baroreceptors that sense blood pressure and a small body that senses oxygen and carbon dioxide

Carotid artery — the carotid sinus and carotid body.

Its terminal branch enters the skull through a canal in the petrous temporal bone and helps form a ring of vessels at the base of the brain

Carotid artery — the internal carotid and the circle of Willis.

The right one arises from the brachiocephalic trunk while the left comes straight off the aortic arch

Carotid artery — right and left common carotid arteries.

Surgical removal of atheroma from its internal branch, an endarterectomy, reduces the risk of stroke

Carotid artery — carotid endarterectomy.

Key ideas

  • The internal branch has no branches in the neck and enters the skull through the carotid canal; the external branch gives eight named branches, including the facial, lingual and superficial temporal arteries.
  • Carotid sinus massage can slow the heart by a vagal reflex; it can also cause fainting.

Quick-fire facts

  • •The common carotid gives off no branches until it divides; the left is a few centimetres longer than the right because it arises from the arch rather than the brachiocephalic trunk.
  • •It bifurcates at the level of the upper border of the thyroid cartilage, about C4.
  • •The internal carotid enters the skull via the carotid canal in the temporal bone and helps form the circle of Willis.
  • •The external carotid gives off superior thyroid, ascending pharyngeal, lingual, facial, occipital, posterior auricular, maxillary and superficial temporal branches.
  • •The carotid pulse is a preferred central pulse for resuscitation; it should not be pressed on both sides at once.
  • •The carotid sheath also contains the internal jugular vein (lateral) and vagus nerve (posterior).
  • •Carotid duplex ultrasound is used to detect stenosis, a cause of transient ischaemic attack and stroke.
  • •The carotid body is a chemoreceptor; the carotid sinus is a baroreceptor supplied by the glossopharyngeal nerve.

Drill it — 7 cards

1 / 7new card

Sources