Major Arteries of the Head and Neck
The head and neck receives the majority of its blood supply through the carotid and
vertebral arteries. This article shall explore the anatomy of this arterial system – its
anatomical course, branches, and clinical correlations.
Carotid Arteries
We shall start at the origin of the carotid arteries. The right common carotid artery
arises from a bifurcation of the brachiocephalic trunk (the right subclavian artery is
the other branch). This bifurcation occurs roughly at the level of the right
sternoclavicular joint.
The left common carotid artery branches directly from the arch of aorta. The left and
right common carotid arteries ascend up the neck, lateral to the trachea and the
oesophagus. They do not give o any branches in the neck.
At the level of the superior margin of the thyroid cartilage (C4), the carotid arteries
split into the external and internal carotid arteries. This bifurcation occurs in an
anatomical area known as the carotid triangle.
The common carotid and internal carotid are slightly dilated here, this area is known
as the carotid sinus, and is important in detecting and regulating blood pressure.
Fig 1.0 – Origin of the blood vessels of the upper limb. Note how the left common
carotid and subclavian arteries arise directly from the arch of aorta.
, Fig 1.1 – Lateral vein of the neck, showing the origin and bifurcation of the
common carotid artery.
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Clinical Relevance: Carotid Sinus Hypersensitivity
The carotid sinus is a dilated portion of the common carotid artery and proximal
internal carotid artery. It contains baroreceptors: specialised sensory cells. The
baroreceptors detect stretch as a measure of blood pressure. The
glossopharyngeal nerve feeds this information to the brain, and this is used to
regulate blood pressure.
In some individuals, the baroreceptors are hypersensitive to stretch. External
pressure on the carotid sinus can cause slowing of the heart rate and a decrease
in blood pressure. The brain becomes under-perfused and syncope results. In such
patients, checking the pulse at the carotid triangle is not advised.
External to the carotid sinus, there is a cluster of nervous cells known as the carotid
body. These cells act as peripheral chemoreceptors; detecting the O2 content of
the blood and relaying this information to the brain to regulate breathing rate.
External Carotid Artery
The external carotid artery supplies the areas of the head and neck external to the
cranium. After arising from the common carotid artery, it travels up the neck, passing
posteriorly to the mandibular neck and anteriorly to the lobule of the ear.
The head and neck receives the majority of its blood supply through the carotid and
vertebral arteries. This article shall explore the anatomy of this arterial system – its
anatomical course, branches, and clinical correlations.
Carotid Arteries
We shall start at the origin of the carotid arteries. The right common carotid artery
arises from a bifurcation of the brachiocephalic trunk (the right subclavian artery is
the other branch). This bifurcation occurs roughly at the level of the right
sternoclavicular joint.
The left common carotid artery branches directly from the arch of aorta. The left and
right common carotid arteries ascend up the neck, lateral to the trachea and the
oesophagus. They do not give o any branches in the neck.
At the level of the superior margin of the thyroid cartilage (C4), the carotid arteries
split into the external and internal carotid arteries. This bifurcation occurs in an
anatomical area known as the carotid triangle.
The common carotid and internal carotid are slightly dilated here, this area is known
as the carotid sinus, and is important in detecting and regulating blood pressure.
Fig 1.0 – Origin of the blood vessels of the upper limb. Note how the left common
carotid and subclavian arteries arise directly from the arch of aorta.
, Fig 1.1 – Lateral vein of the neck, showing the origin and bifurcation of the
common carotid artery.
+
Clinical Relevance: Carotid Sinus Hypersensitivity
The carotid sinus is a dilated portion of the common carotid artery and proximal
internal carotid artery. It contains baroreceptors: specialised sensory cells. The
baroreceptors detect stretch as a measure of blood pressure. The
glossopharyngeal nerve feeds this information to the brain, and this is used to
regulate blood pressure.
In some individuals, the baroreceptors are hypersensitive to stretch. External
pressure on the carotid sinus can cause slowing of the heart rate and a decrease
in blood pressure. The brain becomes under-perfused and syncope results. In such
patients, checking the pulse at the carotid triangle is not advised.
External to the carotid sinus, there is a cluster of nervous cells known as the carotid
body. These cells act as peripheral chemoreceptors; detecting the O2 content of
the blood and relaying this information to the brain to regulate breathing rate.
External Carotid Artery
The external carotid artery supplies the areas of the head and neck external to the
cranium. After arising from the common carotid artery, it travels up the neck, passing
posteriorly to the mandibular neck and anteriorly to the lobule of the ear.
