This presentation is about the arteries of carotid triangle in detail.

1. Arteries of Carotid
Triangle

2. Common Carotid Artery
The right common carotid artery is a branch of the
brachiocephalic artery.
It begins in the neck behind the right sternoclavicular
joint.
The left common carotid artery is branch of the
arch of the aorta.
It begins in the thorax in front of the trachea opposite
a point a little to the left of the centre of the
manubrium.
It ascends to the back of left sternoclavicular joint
and enters the neck.
In the neck, both arteries have a similar course.
Each artery runs upwards within the carotid sheath,
under cover of the anterior border of the
sternocleidomastoid.
It lies in front of the lower four cervical transverse
processes.
At the level of the upper border of the thyroid
cartilage, the artery ends by dividing into the external
and internal carotid arteries

3. Carotid Sinus
The termination of the common carotid artery,
or the beginning of the internal carotid artery
shows a slight dilatation, known as the carotid
sinus.
In this region, the tunica media is thin,
but the adventitia is relatively thick and
receives a rich innervation from the
glossopharyngeal and sympathetic nerves.
The carotid sinus acts as a baroreceptor of
pressure receptor and regulates blood pressure

4. Carotid Body
• Carotid body is a small, oval reddish brown
structure
• situated behind the bifurcation of the common
carotid artery.
• It receives a rich nerve supply mainly from the
glossopharyngeal nerve, but also from the vagus
and sympathetic nerves.
• It acts as a chemoreceptor and responds to
changes in the oxygen, carbon dioxide and
pH content of the blood.
• Other allied chemoreceptors are found near the
arch of the aorta, the ductus arteriosus, and the
right subclavian artery. These are supplied by
the vagus nerve.

5. Clinical Anatomy
• The carotid sinus is richly supplied by nerves.
• In some persons, the sinus may be hypersensitive. In such
persons, sudden rotation of the head may cause slowing of heart.
This condition is called as "carotid sinus syndrome".
• The supraventricular tachycardia may be controlled by carotid
sinus massage/ due to inhibitory effects of vagus nerve on the
heart.
• The necktie should not be tied tightly, as it may compress both
the internal carotid arteries, supplying the brain.

6. External Carotid Artery
Course & Relations
The external carotid artery begins in the carotid triangle at
the level of the upper border of the thyroid cartilage opposite
the disc between the third and fourth cervical vertebrae.
It runs upwards and slightly backwards and laterally, and
terminates behind the neck of the mandible by dividing into
the maxillary and superficial temporal arteries.
The external carotid artery has a slightly curved course, so
that it is anteromedial to the internal carotid artery in its lower
part, and anterolateral to the internal carotid artery in its upper
part.
ln the carotid triangle, the external carotid artery is
comparatively superficial, and lies under cover of the anterior
border of the sternocleidomastoid.
The artery is crossed superficially by the cervical branch of
the facial nerve, the hypoglossal nerve, and the facial, lingual
and superior thyroid veins.

7. Deep to the artery, there are:
a. The wall of the pharynx.
b. The superior laryngeal nerve which divides into the
external and internal laryngeal nerves.
c. The ascending pharyngeal artery
Above the carotid triangle, the external carotid artery lies
deep in the substance of the parotid gland. Within the gland, it
is related superficially to the retromandibular vein and the
facial nerve
Deep to the external carotid artery, there are:
a. The internal carotid artery.
b. Structures passing between the external and internal
carotid arteries; these being styloglossus, stylopharyngeus, IX
nerve, pharyngeal branch of X, and styloid process.
c. Two structures deep to the internal carotid artery, namely
the superior laryngeal nerve and the superior cervical
sympathetic ganglion

8. Branches
The external carotid artery gives off eight branches
which may be grouped as follows.
Anterior
1. Superior thyroid
2. Lingual
3. Facial
Posterior
1. Occipital
2. Posterior auricular.
Medial
1. Ascending pharyngeal
Terminal
1. Maxillary
2. Superficial temporal

9. Superior Thyroid Artery
• arises from the external carotid artery just below the
level of the greater cornua of the hyoid bone.
• runs downwards and forwards parallel and just
superficial to the external laryngeal nerve.
• passes deep to the three long infrahyoid muscles to
reach the upper pole of the lateral lobe of the thyroid
gland.
• relationship to the external laryngeal nerve, which
supplies the cricothyroid muscle is important to the
surgeon during thyroid surgery.
• The artery and nerve are close to each other higher
up, but diverge slightly near the gland.
• To avoid injury to the nerve, the superior thyroid artery
is ligated as near the gland as possible
• Apart from its terminal branches to the thyroid gland, it
gives one important branch, the superior laryngeal
artery which pierces the thyrohyoid membrane in
company with the internal laryngeal nerve
• The superior thyroid artery also gives a
sternocleidomastoid branch to that muscle and a
cricothyroid branch that anastomoses with the artery
of the opposite side in front of the cricovocal
membrane.

10. Lingual Artery
• arises from the external carotid artery opposite the tip of
the greater cornua of the hyoid bone.
• It is tortuous in its course.
• Its course is divided into three parts by the hyoglossus
muscle.
• The first part lies in the carotid triangle.
• It forms a characteristic upward loop which is crossed by the
hypoglossal nerve.
• The lingual loop permits free movements of the hyoid bone.
• The second part lies deep to the hyoglossus along the
upper border of hyoid bone.
• It is superficial to the middle constrictor of the pharynx.
• The third part is called the arteria profunda linguae, or
the deep lingual artery.
• It runs upwards along the anterior border of the hyoglossus,
and then hoizontally forwards on the undersurface of the
tongue as the fourth part.
• In its vertical course, it lies between the genioglossus
medially and the inferior longitudinal muscle of the tongue
laterally.
• The horizontal part of the artery is accompanied by the
lingual nerve.
• During surgical removal of the tongue, the first part of the
artery is ligated before it gives any branch to the tongue or
to the tonsil.
1 2
3

11. Facial Artery:
arises from the external carotid just above the tip of the
greater cornua of the hyoid bone.
It runs upwards first in the neck as cervical part and then on
the face as facial part. The course of the artery in both
places is tortuous.
The tortuosity in the neck allows free movements of the
pharynx during deglutition. On the face, it allows free
movements of the mandible, the lips and the cheek during
mastication and during various facial expressions.
The artery escapes traction and pressure during these
movements.
The cervical part of the facial artery runs upwards on the
superior constrictor of pharynx deep to the posterior belly of
the digastric, with the stylohyoid and to the ramus of the
mandible.
It grooves the posterior border of the submandibular salivary
gland.
Next the artery makes an S-bend (two loops) first winding
down over the submandibular gland, and then up over the
base of the mandible
The facial part of the facial artery enters the face at
anteroinferior angle of masseter muscle, runs upwards close
to angle of mouth, side of nose till medial angle of eye.

12. The cervical part of the facial artery gives off
1. ascending palatine,
2. tonsillar,
3. submental, and
4. glandular branches for the submandibular salivary gland
and lymph nodes.
The ascending palatine artery arises near the origin of the
facial artery. It passes upwards between the styloglossus
and the stylopharyngeus, crosses over the upper border of
the superior constrictor and supplies
the tonsil and the root of the tongue.
The submental branch is a large artery which
accompanies the mylohyoid nerve, and supplies the
submental triangle and the sublingual salivary gland.

13. The facial part
It enters the face by winding around the base of the mandible, and by piercing
the deep cervical fascia, at the anteroinferior angle of the masseter muscle.
It can be palpated here and is called ‘anaesthetist's artery'.
First it runs upwards and forwards to a point 1.25 cm lateral to the angle of the
mouth.
Then it ascends by the side of the nose up to the medial angle of the eye,
where it terminates by supplying the lacrimal sac; and by anastomosing with
the dorsal nasal branch of the ophthalmic artery.
The facial artery is very tortuous.
The tortuosity of the artery prevents its walls from being unduly stretched
during movements of the mandible, the lips and the cheeks.
It lies between the superficial and deep muscles of the face.
Branches
The anterior branches on the face are large and named.
They are:
1. lnferior labial, to the lower lip.
2. Superior labial, to the upper lip and the anteroinferior part of the nasal
septum.
3. Lateral nasal, to the ala and dorsum of the nose.
The posterior branches are small and unnamed.
Anastomoses
1. The large anterior branches anastomose with similar branches of the
opposite side and with the mental artery. In the lips, anastomoses are large, so
that cut arteries spurt from both ends
2. Small posterior branches anastomose with the transverse facial and
infraorbital arteries.
3. At the medial angle of the eye, terminal branches of the facial artery
anastomose with branches of the ophthalmic artery. This is, therefore, a site for
anastomoses between the branches of the external and internal carotid arteries

14. Occipital Artery
The occipital artery arises from the posterior
aspect of the external carotid artery, opposite
the origin of the facial artery
It is crossed at its origin by the hypoglossal
nerve.
In the carotid triangle, the artery gives two
sternocleidomastoid branches.
The upper branch accompanies the
accessorynerve, and the lower branch
arises near the origin of the occipital artery

15. Posterior Auricular Artery
The posterior auricular artery arises from the
posterior aspect of the external carotid just
above the posterior belly of the digastric.
It runs upwards and backwards deep to the
parotid
gland, but superficial to the styloid process.
It crosses the base of the mastoid process, and
ascends behind the auricle.
It supplies the back of the auricle, the skin over
the mastoid process, and over the back of the
scalp.
It is cut in incisions for mastoid operations.
Its stylomastoid branch enters the stylomastoid
foramen, and supplies the middle ear, the
mastoid antrum and air cells, the semicircular
canals, and the facial nerve.

16. Ascending Pharyngeal Artery
This is a small branch that arises from the medial
side of the external carotid artery.
It arises very close to the lower end of external
carotid artery.
It runs vertically upwards between the side wall of
the pharynx, and the tonsil, medial wall of the
middle ear and, the auditory tube.
It sends meningeal branches into the cranial cavity
through the foramen lacerum, the jugular foramen
and the hypoglossal canal

17. Maxillary Artery
This is the larger terminal branch of the external
carotid artery.
It begins behind the neck of the mandible under
cover of the parotid gland.
It runs forwards deep to the neck of the mandible
below the auriculotemporal nerve, and enters the
infratemporal fossa

18. Superficial Temporal Artery
1. It is the smaller terminal branch of the extemal
carotid artery.
It begins, behind the neck of the mandible under
cover of the parotid gland.
2. It runs vertically upwards, crossing the root of the
zygoma or preauricular point, where its pulsations
can be easily felt.
About 5 cm above the zygoma, it divides into
anterior and posterior branches which supply the
temple and scalp.
The anterior branch anastomoses with the
supraorbital and supratrochlear branches of the
ophthalmic artery.
3. In addition to the branches which supply the
temple, the scalp, the parotid gland, the auricle and
the facial muscles,
the superficial temporal artery gives off a
transverse facial artery, and a middle temporal
artery which runs on the temporal fossa deep to the
temporalis muscle