Blood Supply to the Head and Neck
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The
brain | Main Anatomy
Index | The face
Last updated 30 March 2006
Blood Supply
to the Head and Neck
- Most arteries in the anterior
cervical triangle arise from the common
carotid artery or one of the branches of the external
carotid artery. Click
here for blood supply to the brain.
- Most veins in the anterior cervical
triangle are tributaries of the large internal
jugular vein. Click here
for the venous sinuses of the dura mater.
The Common Carotid Arteries (p. 804)
- The right common carotid
artery begins at the bifurcation of the brachiocephalic
trunk, posterior to the right sternoclavicular joint.
- The left common carotid
artery begins arises from the arch of the aorta and
ascends into the neck, posterior to the left
sternoclavicular joint.
- Each common carotid artery ascends into the neck within the carotid sheath to
the level of the superior border of
the thyroid cartilage.
- Here it terminates by dividing into the internal and
external carotid arteries.
The Internal Carotid Artery (p. 804)
- This is the direct continuation of the common carotid
artery and it has no branches in
the neck.
- It supplies structures inside the skull.
- The internal carotid arteries are two of the four main
arteries that supply blood to the brain.
- Each artery arises from the common carotid at the level
of the superior border of the thyroid cartilage.
- It then passes superiorly, almost in a vertical plane, to
enter the carotid canal
in the petrous part of
the temporal bone.
- A plexus of sympathetic fibres
accompany it.
- During its course through the neck, the internal carotid
artery lies on the longus capitis
muscle and the sympathetic trunk.
- The vagus nerve
(CN X) lies posterolateral to it.
- The internal carotid artery enters the middle
cranial fossa beside the dorsum sellae of the
sphenoid bone.
- Within the cranial cavity, the internal carotid artery
and its branches supply the hypophysis cerebri (pituitary
gland), the orbit, and most of the supratentorial part of
the brain.
- Click here
to go to the internal carotid artery in the blood supply
of the brain.
The External Carotid Arteries (p. 805)
Click here for a
diagram of the external carotid artery and its branches.
- This vessel begins at the bifurcation of the common
carotid, at the level of the superior border of the
thyroid cartilage.
- It supplies structures external to
the skull.
- The external carotid artery runs posterosuperiorly to the
region between the neck of the
mandible and the lobule of the auricle.
- It terminates by dividing into two branches, the maxillary and superficial
temporal arteries.
- The stems of most of the six
branches of the external carotid artery are in
the carotid triangle.
The
Superior Thyroid Artery (p. 805)
- This is the most inferior of the 3
anterior branches of the external carotid.
- It arises close to the origin of the vessel, just inferior to the greater horn of the hyoid.
- The superior thyroid artery runs anteroinferiorly, deep
to the infrahyoid
muscles and gives off the superior
laryngeal artery. This artery pierces the thyrohyoid
membrane in company with the internal laryngeal nerve
and supplies the larynx.
The
Lingual Artery (p. 805)
- This arises from the external carotid artery as it lies
on the middle constrictor muscle
of the pharynx.
- It arches superoanteriorly, about 5
mm superior to the tip of the greater horn of the hyoid
bone, and then passes
deep to the hypoglossal nerve, the stylohyoid
muscle, and the posterior belly of digastric muscle.
- It disappears deep to the hyoglossus muscle.
- At the anterior border of this muscle, it turns
superiorly and ends by becoming the deep
lingual artery.
The Facial Artery (p. 805)
- This arises from the carotid artery either, in common
with the lingual artery, or immediately superior to it.
- In the neck the facial artery gives off its important tonsillar branch and branches
to the palate and submandibular
gland.
- The facial artery then passes superiorly under the cover
of the digastric and stylohyoid
muscles and the angle of the mandible.
- It loops anteriorly and enters a deep
groove in the submandibular gland.
- The facial artery hooks around the inferior border of the
mandible and enters the face. Here the pulsation of this
artery can be felt (anterior to the masseter muscle).
- Click here to go the
facial artery in the face.
The
Ascending Pharyngeal Artery (p. 805)
- This is the 1st or 2nd branch of
the external carotid artery.
- This small vessel ascends on the pharynx, deep to the internal carotid artery.
- It sends branches to the pharynx, prevertebral muscles,
middle ear and meninges.
The
Occipital Artery (pp. 805-6)
- This arises from the posterior surface of the external
carotid near the level of the facial artery.
- It passes posteriorly along the inferior
border of the posterior belly of
digastric.
- It ends in the posterior part of the scalp.
- During its course, it is superficial to the internal
carotid artery and three cranial nerves (CN IX, CN X and
CN XI).
The
Posterior Auricular Artery (p. 806)
- This is a small posterior branch of the external carotid
artery.
- It arises from it at the superior border of the posterior
belly of the digastric muscle.
- It ascends posteriorly to the external acoustic meatus
and supplies adjacent muscles,
the parotid gland, the facial nerve, structures in
the temporal bone, the auricle,
and the scalp.
The Internal Jugular Vein (pp. 806-7)
Click here for a
diagram on the internal jugular vein and its tributaries.
- This is usually the largest vein in
the neck.
- The internal jugular vein drains blood from the brain and
superficial parts of the face and neck.
- Its course corresponds to a line drawn from a point immediately inferior to the external
acoustic meatus to the medial
end of the clavicle.
- This large vein commences at the jugular
foramen in the posterior cranial fossa, as the
direct continuation of the sigmoid
sinus.
- The dilation at its origin is called the superior bulb of the internal jugular
vein.
- From here it runs inferiorly through the neck in the carotid sheath.
- The internal jugular vein leaves the anterior triangle of
the neck by passing deep to the SCM muscle.
- Posterior to the sternal end of the clavicle, it unites
with the subclavian vein to form the brachiocephalic
vein.
- Near its termination is the inferior
bulb of the jugular vein contains a bicuspid valve similar to that
of the subclavian vein.
- The deep cervical lymph nodes
lie along the course of the internal jugular vein, mostly
lateral and posterior.
Tributaries of the Internal Jugular Vein (p.
807)
- This large vein is joined at its origin by the: inferior petrosal sinus, the facial, lingual,
pharyngeal, superior and middle thyroid veins, and
often the occipital
vein.