Anatomy of the external carotid artery (ECA)

Interventional Neuroradiology
Anatomy
External Carotid Artery (ECA)
Mohamed M.A. Zaitoun, MD
Interventional Radiology Consultant, Zagazig University Hospitals, Egypt
FINR-Switzerland
zaitoun82@gmail.com
Interventional Radiology Unit,
Zagazig University, Egypt

Knowing as much as possible
about your enemy precedes
successful battle and learning
about the disease process
precedes successful
management.

External Carotid Artery (ECA)
a) Origin
b) Supply
c) Course
d) Branches

a) Origin :
-Bifurcation of the common carotid artery
b) Supply :
-The ECA supplies the tissues of the scalp , face
and neck
-These include the skin and superficial soft tissues
of the head , facial adnexa , cranial nerves and
the support structures associated with the
special senses , upper airway and alimentary
systems

-Lateral 2D view
following
selective external carotid
artery injection , there is
a hypervascular mass
adjacent to the proximal
ECA
This is the typical
appearance of a carotid
body tumor (glomus or
paraganglioma)
6 occipital artery
9 lingual artery
10 facial artery
11 superficial temporal
artery
12 internal maxillary
artery
13 middle meningeal
artery

-Lateral 3D view following left
common carotid artery
injection , note the
hypervascular mass typical of
a carotid body tumor (glomus
or paraganglioma) situated
between the proximal internal
and external carotid arteries
1 common carotid artery
2 internal carotid artery
3 external carotid artery
4 ascending pharyngeal
artery
7 superior thyroid artery
9 lingual artery
10 facial artery

c) Course :
-It arises at the level of the superior border of the
thyroid cartilage and terminates beneath the
neck of the mandible by dividing into superficial
temporal and internal maxillary arteries
-At its origin , it is situated anterior to the ICA but
as it ascends , it lies more posteriorly and finally
lateral to ICA
-Thus , on frontal angiography its origin is medial
to the ICA origin and the vessels reverse their
relative positions as they run superiorly but on
the lateral view the ICA is always posterior

-The ECA lies lateral to the pharynx and
medial to the sternocleidomastoid muscle
-At the angle of the mandible , it lies deep to
the posterior belly of digastric and
stylohyoid muscles before entering the
parotid gland , it divides into the superficial
temporal and maxillary arteries within the
parotid gland

d) Branches :
-It has eight branches which will be described in
their usual sequence from proximal to distal
-These are :
1-Superior Thyroid artery
2-Lingual artery
3-Ascending Pharyngeal artery (APA)
4-Facial artery (FA)
5-Occipital artery (OA)
6-Posterior Auricular artery (PA)
7-Superficial Temporal artery (STA) (terminal)
8-Internal Maxillary artery (IMA) (terminal)

Black key
1 ascending thoracic aorta
2 descending thoracic aorta
3 innominate artery
4 right subclavian artery
5 stump of right common carotid
artery
6 right vertebral artery
7 right thyrocervical trunk
8 right costocervical trunk
9 right internal mammary artery
10 left subclavian artery
11 left vertebral artery
12 left thyrocervical trunk
13 left costocervical trunk
14 left internal mammary artery
15 left common carotid artery

Red key
5 occipital artery
6 posterior auricular artery
9 lingual artery
10 facial artery
12 internal maxillary artery
24 transverse facial artery

-Frontal left common
carotid artery injection ,
normal 2D appearance of
the left common carotid
artery bifurcation region
2b carotid bulb
5 occipital artery
9 lingual artery
10 facial artery

-Lateral left common
2b carotid bulb
5 occipital artery
9 lingual artery
10 facial artery

-Frontal following left common
carotid artery injection , there
is a normal 3D appearance of
the left common carotid artery
bifurcation region
2b carotid bulb
5 occipital artery
9 lingual artery
10 facial artery

-lateral following left
injection , there is a
2b carotid bulb
5 occipital artery
9 lingual artery
10 facial artery

-Posterior following left
injection , there is a
2b carotid bulb
5 occipital artery
9 lingual artery
10 facial artery

-Right anterior oblique view
following left common
there is a normal 3D
appearance of the left
bifurcation region
2b carotid bulb
5 occipital artery
9 lingual artery
10 facial artery

-The anterior branches of ECA supply the face and
its adnexa , i.e. the facial artery and the internal
maxillary artery (supported by the superior
thyroid , lingual and superficial temporal arteries)
-The principal arteries to the superficial structures
of the skull are the superficial temporal artery
anteriorly (supported by the facial artery) and
posteriorly the occipital artery (supported by the
posterior auricular artery)

-The IMA supplies the anterior deeper structures ,
i.e. the meninges (via the middle meningeal
artery) with the occipital artery supported by the
posterior auricular , supplying the posterior
meninges
-The APA territory is the key to understanding the
blood supply to the skull base since it supplies
the intermediate zone bordered anteriorly by the
IMA territory and posteriorly by the occipital
artery territory , its embryological heritage as a
third branchial arch artery links it to the ICA and
so its importance bears no relation to its
apparently insignificant size

-The external carotid artery terminates by
dividing into the superficial temporal artery
(STA) and internal maxillary artery (IMA)
just above the neck of the mandible within
the parotid gland

1-Superior Thyroid artery :
a) Origin
b) Course
c) Branches
d) Termination

a) Origin :
-This artery arises from the anterior surface
of the ECA , close to its origin
b) Course :
-It describes an inferior concave curve as it
runs medially to gain the superior apex of
the thyroid gland

c) Branches :
1-Small infrahyoid artery (which contributes to the
submental anastomoses)
2-Branch to the sternocleidomastoid muscle
3-The superior laryngeal artery (which supplies the
mucosa of the larynx)
4-Cricothyroid branch
d) Termination :
-It terminates by dividing into anterior and posterior
branches to supply the thyroid gland

-Common carotid
injection in a patient with
a thyroid adenoma
-A hypervascular blush
is seen from an enlarged
superior thyroidal artery
(s.thy.a.)
ap., ascending palatine
apa., ascending
pharyngeal
o., occipital artery
ima., internal maxillary
pa., posterior auricular f.,
facial artery
la., lingual artery

2-Lingual artery :
a) Origin
b) Course
c) Branches
d) Termination

a) Origin :
-This artery arises from the anterolateral
border of the ECA at the level of the
greater cornu of the hyoid bone or from a
common lingofacial trunk with the facial
artery

b) Course :
-It runs forwards and initially loops upwards ,
where it crosses the hypoglossal nerve and then
downwards and forwards on the middle
constrictor muscle , deep to the hyoglossus
muscle
-Finally , it ascends, between the genioglossus
muscle and the anterior border of hyoglossus
muscle, and runs forwards into the base of the
tongue , it gives small branches before
terminating in the dorsal artery of the tongue
which gives a series of characteristic parallel
end arteries

c) Branches :
1-Posterior to the hyoglossus muscle , it
gives the small suprahyoid artery
2-Anterior to the hyoglossus muscle the
sublingual artery which supplies the
sublingual gland , adjacent mucosa and
anterior mandible
3-The main trunk then sweeps forwards as
the dorsal artery of the tongue

d) Termination :
-The dorsal artery of the tongue (which may arise
as two or more branches) runs upwards to
vascularise the mucosa at the base of the
tongue and sends small branches posteriorly as
far as the palatine tonsil
-In its most anterior portion, it is sometimes called
the deep lingual artery, where it runs parallel to
the frenulum , supplying the muscle and mucosa
of the tongue
-Though there is a rich anastomosis with proximal
branches of the facial artery at the base of the
tongue , there are no anastomoses between the
muscular arterial networks and the two halves of
the tongue , embolisation of this section of the
lingual artery is thus not advised because of the
risk of causing necrosis

1-Common Carotid Artery
2-Internal Carotid Artery
3-Ascending pharyngeal Artery
4-Occipital Artery
5-Superficial Temporal Artery
6-Middle cerebral Artery
7-Anterior cerebral Artery
8-Middle meningeal Artery
9-Maxillary artery
10-Facial artery
11-Lingual artery
12-External carotid artery
13-Superior thyroid artery

3-Ascending Pharyngeal artery (APA) :
a) Origin
b) Course
c) Divisions

a) Origin :
-The ascending pharyngeal artery arises
from the posteromedial surface of the ECA
at the same level as the lingual artery (or
occasionally from the ICA)

b) Course :
-Its trajectory is vertical , lying on the longus
capitis muscle between the carotid sheath
and the lateral wall of the pharynx
-It supplies the mucosa and muscles of the
pharynx, prevertebral muscles and dura of
the posterior fossa and craniocervical
junction

c) Divisions :
-The trunk divides into two divisions (anterior
& posterior) , a variable distance after its
origin and gives branches that may arise
from the main trunk or proximal parts of
either division

1-Anterior division (Pharyngeal) : (Anteriorly ,
Extracranial)
-Pharyngeal branches arise from an anterior
division of the main artery (pharyngeal trunk)
-These supply pharyngeal muscles and mucosa in
a series of branches :
1-Inferior pharyngeal artery
2-Middle pharyngeal artery
3-Superior pharyngeal artery
4-Palatine branches
5-Prevertebral branches

1-Inferior Pharyngeal artery :
-Supplies the hypopharynx
2-Middle Pharyngeal artery :
-Supplies the oropharynx and soft palate
and take part in the pharyngeal
anastomoses

3-Superior Pharyngeal artery :
-Supplies the nasopharynx and is the major
contributors to the pharyngeal
anastomoses
-Branches anastomose with the accessory
meningeal artery in the region of the
foramen spinosum , this is one of several
potential anastomotic routes to branches
of the ILT

-Another is via a branch to the foramen
lacerum which is an anastomotic route to
the ILT via the recurrent branch of the
foramen lacerum
-They also anastomose with branches of the
IMA around the Eustachian tube , i.e. with
the pterygovaginal and Vidian arteries

A microcatheter injection of the right ascending pharyngeal artery , lateral projection , shows a
pronounced tumor blush corresponding with the sagittal appearance of the tumor , the
pharyngeal trunk (P) and hypoglossal branch (H) of the neuromeningeal trunk are well
seen , the superior pharyngeal branch of the pharyngeal trunk anastomoses to the territory
of the internal maxillary artery via the pterygovaginal artery (PV) , this results in
opacification of the inferolateral trunk (ILT) via the artery of the foramen rotundum , the
superior pharyngeal artery may also connect with the middle cranial fossa via the foramen
lacerum through its carotid branch (C) , the vertebral artery (VA) is transiently opacified on
this injection

4-Palatine branches :
-Are small branches which pass medially on the
superior pharyngeal constrictor muscle and
supply the soft palate and tonsil and take part in
an anastomosis with the descending palatine
artery of the IMA and the branches around the
Eustachian tube
-They may take the place of the ascending
palatine artery (from the facial artery) if it is small

5-Prevertebral branches :
-Are small branches which supply the longus
capitis and colli muscles , the sympathetic
trunk , the Xth cranial nerve and the lymph
node chain as the trunk ascends
-They anastomose with branches of the
ascending cervical artery

2-Posterior Division (Neuromeningeal
Trunk) : (Posteriorly , Intracranial)
-Is also a long straight artery diverging
posteriorly from the pharyngeal trunk ,
ascending to overlap the foramen magnum
on the lateral view , its major posteriorly
directed branches are the hypoglossal artery
and the jugular artery , the hypoglossal artery
is the more medial of the two branches on the
AP view

a) Hypoglossal artery :
-Is important because of the variety of zones
to which it contributes branches
-It supplies the hypoglossal (XIIth) cranial
nerve in the hypoglossal canal and dura of
the anterior posterior fossa and foramen
magnum region and contributes to the
odontoid arcade

-Branches after passing through the hypoglossal
canal :
1-Clival branches :
-Which run superiorly onto the clivus and
anastomose with the medial clival branch of the
meningohypophyseal trunk
2-Branches to the meninges of the posterior
fossa:
-Which reciprocate their territory with the jugular
artery , it anastomoses with the small anterior
meningeal artery which is a branch of the
vertebral artery

3-Descending branches :
-Which enter the spinal canal through the foramen
magnum
-They give dural branches to the odontoid arcade
-These are best called prevertebral arteries ,
though this term is sometimes confusingly used
for the entire descending branch which
descends to the C3 intervertebral space to
anastomose with the C3 spinal artery of the VA
-They anastomose with musculospinal branches of
the ascending cervical artery

AP view of right Hypoglossal division microcatheter injection with exquisite
demonstration of the odontoid arcade , a descending branch of the RT
hypoglossal division opacifies the arcade with visualization of the
contralateral AP anastomosis and vertebral arteries , the arcade is seen to
advantage because the remainder of right hypoglossal division has been
embolized , thereby diverting flow into the arcade

b) Jugular artery :
-Arises lateral to the neuromeningeal trunk and is
the larger of the two main posterior division
branches
-It runs upwards and medially to enter the cranium
through the jugular foramen
-In the foramen , it supplies cranial nerves IXth ,
Xth and XIth and the glomus jugulare before
continuing to supply dura in the posterior fossa
(it reciprocates this territory with the hypoglossal
artery)

Angiogram (A) and diagram (B) of the ascending pharyngeal artery
anastomoses to the vertebral artery via the hypoglossal branch and
musculospinal branch , Top, superior view ; bottom, inferior view ; left,
anterior view ; right, posterior view

-After leaving the foramen , it gives a small medial branch
which runs superiorly on the clivus to supply the VIth
cranial nerve and continues posterolaterally giving dural
branches to supply dura over a variable but usually wider
area than branches of the hypoglossal artery
-Its branches to the dura of the lateral clivus anastomose
with the lateral clival artery (meningohypophyseal trunk)
and with the dural territories of the middle meningeal ,
posterior auricular and occipital arteries
-From these may arise the artery of the falx cerebelli or the
posterior meningeal artery , the meningeal distribution of
the neuromeningeal trunk in the posterior fossa varies in
extent and can be virtually negligible

Angiogram (A) and diagram (B) of the ascending pharyngeal artery
communication with the internal carotid artery to the lateral clival
branch of the jugular artery

**Other branches of the Ascending pharyngeal artery :
1-Musculospinal arteries :
-Arise from the main trunk or the posterior division (i.e.
neuromeningeal trunk) in the neck and run posteriorly
and upwards
-They supply paraspinal muscles (with branches of the
ascending cervical artery , in the C3 and C4 region , i.e.
segmental levels) , the superior sympathetic ganglion
and the XIth cranial nerve
-They take part in the supply of the upper paraspinal
muscles and thus potentially anastomose with branches
of the deep cervical artery , spinal branch of VA and the
ascending cervical artery

Angiogram (A) and diagram (B) of the odontoid arch system that gives rise
to several branches that supply the first , second and third cervical roots
and the periosteum of the spinous processes and pedicles
Top, superior view ; bottom, inferior view ; left, anterior view ; right,
posterior view

2-The Inferior Tympanic artery :
-Is a small but important artery
-It is classically described as a branch that arises
from the anterior division (or superior pharyngeal
branch) but may arise from APA or its posterior
division
-It reaches the middle ear via the inferior tympanic
canal (i.e. canal of Jacobson) to supply the
cochlear , glomus tympanicum and vestibule
and thereby contributes to the anastomotic
network of the middle ear cavity

- Within the middle ear , the inferior tympanic
artery anastomoses with :
a) The stylomastoid branch of the occipital
artery , which enters the middle ear via the
canal of that name , running with the VIIth
nerve
b) The petrosal branch of the middle meningeal
artery
c) The caroticotympanic branch of the internal
carotid artery

-Angiogram (A) and diagram (B) of the inferior tympanic artery arising as a
separate branch between the pharyngeal and neuropharyngeal trunks
Top, superior view ; bottom, inferior view ; left, anterior view ; right,
posterior view

4-Facial artery (FA) :
a) Origin
b) Course
c) Branches
d) Termination

a) Origin :
-This artery arises from the anterolateral
surface of the ECA , above the lingual
artery (or from a common trunk with the
lingual artery) and medial to the stylohyoid
and the posterior belly of digastric muscles

b) Course :
-Initially , it lies deep to the mandible and
runs alongside the submandibular gland ,
first upwards and then downwards on its
medial and lateral surfaces
-It then turns under the inferior border of the
mandible (where it is palpable against
bone) to climb obliquely across the face ,
running upwards and forwards

-The FA may cross the cheek as a solitary main
trunk or accompanied by the long facial artery
which arises from its superior surface proximally
and runs posterior to it towards the inner
canthus
-The long facial artery represents one of several
possible branching patterns of the facial artery
on the cheek , sometimes described as jugal
pedicles , these run a parallel course across the
cheek , one above the other

c) Branches :
1-Ascending palatine artery
2-Tonsillar branch
3-Submental artery
4-Glandular branches
5-Jugal branches
6-Labial arteries (superior & inferior labial
arteries)
7-Lateral nasal branch
8-The FA termination into the angular artery
and alar artery

1-Ascending palatine artery :
-Arises close to the origin of the facial artery
and supplies the pharynx , soft palate ,
tonsil and Eustachian tube
2-Tonsillar branch :
-Usually the dominant supply to the palatine
tonsil

3-Submental branch :
-Arises deep to the inferior border of the mandible
and gives branches to the submandibular gland ,
to the mylohyoid and digastric muscles and to
the mandible , including a mental branch
-It anastomoses across the midline and with the
inferior labial branch
-A glandular branch may arise as a separate trunk
of the facial artery , proximal to the submental
artery origin
-During embolisation of the facial artery , in the
context of epistaxis , it is recommended that
superselective catheterization should be
performed distal to the origin of this branch
artery to avoid damaging the gland

4-Glandular branches :
-Are short branches arising as the artery passes
around the gland
5-Jugal branches :
-May arise as a common trunk or as separate
anterior , middle and posterior branches from
the facial artery , the jugal branches are directed
superiorly toward the muscles of the cheek and
masseter muscle , a prominent buccal branch
may be seen connecting this system to the
internal maxillary artery superiorly

6-Labial arteries (superior & inferior
labial arteries) :
-Run forwards to supply the skin and
subcutaneous tissues of the lips
-They anastomose across the midline
-There is a risk of labial necrosis when
embolisation is performed with very small
particles in these vessels

7-Lateral Nasal branch :
-From which branches arise to supply the
side of the nose and which continues
superiorly as the angular artery , i.e. the
terminal trunk of the FA running in the
angle between the nasion and the medial
orbit

8-The FA terminates by dividing into the
angular artery and alar artery :
-The alar artery supplies the nose and takes
part in an extensive network of arteries
arising from both ipsilateral and the
contralateral facial arteries
-The angular artery anastomoses with
medial branches of the OphA , i.e. nasal
and inferior palpebral arteries

d) Termination :
-The FA terminates by dividing into the
angular artery and alar artery

5-Occipital artery (OA) :
a) Origin
b) Course
c) Branches
d) Termination

a) Origin :
-This artery arises from the posterior aspect of the
ECA at the level of the FA
b) Course :
-It passes upwards , laterally and posteriorly
-It crosses lateral to the internal jugular vein and
then passes between the mastoid process and
the transverse process of the atlas

-It gives muscular branches , the transmastoid
artery and the stylomastoid artery , these supply
muscles at the craniocervical junction , the
meninges of the posterior cranial fossa and the
middle ear respectively
-The occipital artery passes through the fascia
between sternomastoid and trapezius and
divides into two superficial branches , one lateral
and one medial , to supply the scalp of the
posterior cranium
-It is a potent route for anastomoses with the
vertebrobasilar system

c) Branches :
1-Muscular branches
2-Stylomastoid artery
3-Transmastoid or artery of the mastoid
foramen
4-Lateral Meningeal arteries
5-Terminal Occipital arteries

1-Muscular branches :
-Which represent segmental arteries supplying the
upper cervical muscles (and nerves and bone)
-They contribute to the territory of the VA branches
at C1 and C2 and anastomose with the spinal
arteries of these spaces
-The muscular branches run posteriorly from their
origins with a characteristic proximal section
directed superiorly and a longer distal section
directed inferiorly , what makes this most striking
is that they run parallel to each other , they
supply the sternocleidomastoid and other
paraspinal muscles in conjunction with branches
of the vertebral artery and the deep cervical
artery

-At C3 and C4 levels , this may include an
overlap with the muscular territory of the
musculospinal arteries of the APA and at
C2 , C3 and C4 with the deep cervical
artery
-A prominent descending muscular branch
may be evident arising at the C1 level
which runs inferiorly to anastomose with
the deep cervical artery at the C3 and C4
levels

2-Stylomastoid artery :
-This branch more frequently arises from the
posterior auricular artery
3-Transmastoid or artery of the mastoid
foramen :
-This branch is usually identifiable as a single
vessel which arises posterior to the stylomastoid
process and gives small muscular branches
before passing intracranially though its foramen
just behind the sigmoid sinus

-It supplies the meninges of the posterior fossa ,
giving branches to the jugular foramen and dura
around the posterior foramen magnum and
adjacent posterior fossa
-These branches thus reciprocate territory with
branches of the jugular and , to a lesser extent ,
the hypoglossal branches of the APA and
posterior meningeal arteries of VA
-A small ascending branch to the internal auditory
canal can anastomose with AICA through the
subarcuate arcade

4-Lateral Meningeal arteries :
-Often arise from the occipital artery as it passes
posteriorly and upwards
-These supply dura in the occipitoparietal region
-They pass though small individual foramen and
their territory borders on the territory of the
posterior branch of the middle meningeal artery
5-Terminal Occipital arteries :
-Which supply the scalp of the posterior cranium
and anastomose across the midline

d) Termination :
-Divides into two superficial branches , one
lateral and one medial , to supply the scalp
of the posterior cranium

6-Posterior Auricular artery (PA) :
a) Origin
b) Course
c) Branches
d) Termination

a) Origin :
-This smaller posterior artery usually arises from
the posterior aspect of the ECA , distal to the OA
or with it as a common trunk
b) Course :
-It passes between the ear and the mastoid
process and terminates in superficial auricular
and occipital branches to the scalp
-It provides branches to the parotid gland ,
adjacent muscles and is the usual source of the
stylomastoid artery

c) Branches :
1-Muscular branches
2-Parotid branches
3-Stylomastoid artery
4-Auricular branches
5-Occipital branches

1-Muscular branches :
-To the adjacent muscles , i.e.
sternocleidomastoid , digastric and
stylohyoid muscles
2-Parotid branches :
-Which are usually small and ignored , but
can theoretically supply the VIIth cranial
nerve

3-Stylomastoid artery :
-This branch runs upwards into the
stylomastoid foramen and supplies the
VIIth cranial nerve , the middle ear and the
mastoid sinuses
-It takes part in the anastomoses within the
middle ear with branches of the middle
meningeal artery , APA & ICA

4-Auricular branches :
-Supply the posterior pinna
5-Occipital branches :
-Supplies the scalp posterior to the ear , in a
reciprocal relationship with the OA

d) Termination :
-Terminates in superficial auricular and
occipital branches to the scalp

7-Superficial temporal artery (STA)
(terminal) :
a) Origin
b) Course
c) Branches

a) Origin :
-The STA is the smaller terminal branch
-It supplies skin and superficial muscles in
an extensive ramification , anastomosing
with the opposite side and the adjacent PA
and OA territories

b) Course :
-It runs on the temporalis muscle, under the
zygomatic arch dividing above the arch into two
main frontal and parietal branches
-These supply the temporalis muscle and scalp of
their named regions
-It provides small branches to supply the parotid
gland and the temporomandibular joint , as well
as the following named branches

c) Branches :
1-Transverse Facial artery
2-Anterior Auricular artery
3-Posterior Deep Temporal artery
4-Zygomatico-Orbital artery
5-Frontal & Parietotemporal Scalp arteries

1-Transverse Facial artery :
-Arises within the parotid gland and runs
horizontally anteriorly above the parotid
duct to supply superficial facial structures
via superior and inferior branches
-It reciprocates its territory with the FA

Transverse facial artery , a lateral slightly skewed projection of the distal external carotid artery
in a patient being studied for intractable epistaxis , there is pronounced blush (B) of nasal
mucosa in the territory of the distal internal maxillary artery (I) , a characteristic 90-degree
turn of the middle meningeal artery (M) is seen as it enters the foramen spinosum , the
accessory meningeal artery (single arrow) is seen as a proximal branch of the middle
meningeal artery ; its branches in the nasopharynx can be seen extending forward to meet
the pterygovaginal branch (PV) of the internal maxillary artery , a prominent vessel running
anteriorly crosses the course of the internal maxillary artery , this is the transverse facial
artery (arrowheads)

Lateral projection of the distal ECA anatomy presents a typical angiographic appearance ,
however , the image must be inspected closely to reveal dangerous anastomoses to the
ophthalmic artery (o.a.) and the internal carotid artery (ICA) via artery of the foramen
rotundum (f.r.), and the inferolateral trunk (i.l.t.)
(Labels: 1, middle meningeal artery; 2, accessory meningeal artery; 3, superficial temporal
artery; 4, middle deep temporal artery; 5, greater descending palatine artery; 6, inferior
alveolar artery; 7, pterygovaginal artery; 8, posterior auricular artery; 9, infraorbital artery;
10, transverse facial artery)

2-Anterior Auricular artery :
-Arises from the STA below the zygomatic arch
and ramifies to supply the anterior external ear
3-Posterior Deep Temporal artery :
-Supplies the temporalis muscle
-It is the smallest of the three possible deep
temporal arteries
-The anterior and middle deep temporal arteries
arise from the IMA

4-Zygomatico-Orbital artery :
-Arises above the zygomatic arch and runs
anteriorly to supply scalp and the
orbicularis oculi muscle
-It takes part in the superficial anastomosis
of arteries around the orbit

Superficial temporal artery to ophthalmic artery anastomoses , a lateral projection of
a CCA injection in the setting of occlusive internal carotid artery disease , it
shows that a frontozygomatic (f.z.) branch of the superficial temporal artery
contributes significantly to retrograde opacification of the ophthalmic artery
(double arrow) , a lesser degree of input is seen from the orbital branch
(arrowhead) of the infraorbital artery (i.o.)

5-Frontal & Parietotemporal Scalp arteries :
-Are distributed over the anterior scalp and
anastomose with their counterparts across the
midline
-The territory of the frontal branches borders those
of the OphA and FA on the forehead and the
parietotemporal branches border the PA and OA
territories over the lateral cranium

8-Internal Maxillary artery (IMA)
(terminal):
a) Origin
b) Course
c) Branches

a) Origin :
-This is the larger terminal branch of the
ECA and arises with STA in the parotid
gland

b) Course :
-It runs medially deep to the mandible to lie either
superficial or deep to the lateral pterygoid
muscle before entering the pterygomaxillary
fissure and passing into the pterygopalatine
fossa
-It traverses the fossa and terminates as the
sphenopalatine artery
-It gives branches to the deep structures of the
face , including muscles of mastication , the
pharynx , orbit , nose as well as the bone and
dura of the anterior skull

c) Branches :
-Its 14 named branches, visible on angiography ,
will be described in the 6 groups (a-f) used by
Djinjian and Merland :
a) Ascending and intracranial arteries
b) Ascending extracranial arteries
c) Descending branches
d) Recurrent arteries
e) Anterior branches to the face
f) Terminal branch (sphenopalatine artery)

a) Ascending and intracranial arteries :
-Destined to vascularise the meninges , ear
and neurocranium
1-Anterior Tympanic artery
2-Middle Meningeal artery
3-Accessory Meningeal artery

1-Anterior Tympanic artery :
-Arises from IMA close to its origin (but may arise
from the ECA termination)
-It supplies the tympanic cavity ,
temporomandibular joint and external ear
-It is difficult to identify on angiography and runs
posteriorly and inferiorly
-It gives the deep auricular artery which
vascularises the external auditory meatus , as
far medially as the tympanic membrane and
branches to the temporomandibular joint and
then enters the squamotympanic fissure and
supplies the malleus and mucosa of the middle
ear

2-Middle Meningeal artery : (MMA)
-Enters the cranial cavity through the foramen
spinosum and ends by dividing into frontal and
parietal branches
-These supply the majority of the convexity
meninges
-After entering the middle cranial fossa through the
foramen spinosum , it gives the following
branches :
a) Petrosal branch
b) Petrosquamal branch
c) Sphenoidal branches
d) Temporal branch

-Frontal 2D
5 occipital artery
9 lingual artery
10 facial artery
11 superficial temporal artery
13 middle meningeal artery
14 accessory meningeal artery
15 deep temporal artery
16 inferior alveolar artery
17 infraorbital artery
18 posterior superior alveolar artery
19 greater palatine artery
20 sphenopalatine artery
25 masseteric muscular branches
26 buccal muscular branches
fs foramen spinosum
m muscular branches
LN lateral nasal branches of
SB septal branches of sphenopalatine
artery

-Lateral 2D
5 occipital artery
9 lingual artery
10 facial artery
fs foramen spinosum
m muscular branches
SB septal branches of

a) Petrosal branch :
-To supply dura of the posterior cavernous sinus
region and reciprocates with the territories of the
petrosquamal branch and the basal tentorial
artery of the meningohypophyseal trunk (ICA)
-It enters the middle ear as the superior tympanic
artery which takes part in the middle ear
anastomosis and supply of the VIIth cranial
nerve

b) Petrosquamal branch or branches :
-Are small and arise after the petrous branch
to supply dura of the middle fossa floor
and part of the anterior tentorium and
cavernous sinus
-They anastomose with branches of the
basal tentorial artery

c) Sphenoidal branches :
-Supply the dura of the anterior part of the
middle fossa floor and extends medially to
supply the planumsphenoidale as well as
branches to the cribriform region and
anterior falx
-A branch may enter the orbit through the
superior orbital fissure (meningo-
ophthalmic artery)

d) Temporal branch :
-Which is often a large vessel that runs posteriorly
on the squamous temporal bone to supply dura
of the lateral middle fossa
-It contributes to the supply of the tentorium and
may supply the posterior falx
-The artery then runs on the inner surface of the
temporal bone to terminate at the pterion by
dividing into frontal (anterior) and parietal
(posterior) branches which supply dura of the
calvarium
-It may give a meningolacrimal branch , in the
middle fossa which enters the lateral orbit via
Hyrtl’s canal

-Lateral 2D view following
common carotid artery injection ,
there is complete occlusion of the
internal carotid artery , the
intracranial internal carotid artery is
reconstituted by flow from the
meningolacrimal branch of the
middle meningeal artery to the
ophthalmic artery with retrograde
flow to the paraclinoid segment of
the internal carotid artery
afr artery of the foramen
rotundum
cb13 cavernous branch of
middle meningeal artery
ILT inferolateral trunk

-Lateral 3D views following
injection , note the various
branches of the external
carotid artery and the
meningolacrimal branch of the
middle meningeal artery
providing flow to the
intracranial internal carotid
artery via retrograde flow
through the ophthalmic artery
artery

-Superior-inferior 3D views
following common carotid
artery injection , note the
various branches of the
external carotid artery and
the meningolacrimal branch
of the middle meningeal
artery providing flow to the
intracranial internal carotid
artery via retrograde flow
through the ophthalmic artery
artery
13 middle meningeal
artery

3-Accessory Meningeal artery :
-Is a small artery which supplies the pharynx
, Eustachian tube and a variable amount
of the dura of the middle cranial fossa
-It arises distal to MMA , but it may arise
from MMA , depending on the relationship
of the IMA to the lateral pterygoid muscle
-The IMA most frequently runs medially ,
deep to the lateral pterygoid and in this
case the accessory meningeal artery
arises directly from IMA

-Lateral 3D view following selective
external carotid artery injection ,
there is a direct hole fistula (arterial-
venous
fistula) between the accessory
meningeal artery and the posterior
aspect of the cavernous sinus
21 artery of the foramen rotundum
22 artery of the pterygoid canal
(vidian
artery)
m muscular branches
CS cavernous sinus
SOV superior ophthalmic vein
SMCV superficial middle cerebral
vein

-If the IMA runs superficial to the muscle , the
MMA and the accessory meningeal artery arise
from a common trunk (hence the latter’s name)
-The two patterns also correlate with the origins of
the inferior alveolar and the middle deep
temporal arteries which arise from a common
temporodental trunk in the deep variant
-Soon after its origin , the accessory meningeal
artery divides into an anterior branch to the
pharynx and Eustachian tube and a posterior
branch which passes through foramen ovale
(anterior to the mandibular nerve , V3) and
supplies the lateral margin of the cavernous
sinus and the Gasserian ganglion

b) Ascending Extracranial arteries :
1-The anterior and middle deep temporal
arteries :
-On angiography , they are visible as middle and
anterior deep temporal arteries and the posterior
deep temporal artery is usually too small or
arises from STA
-The middle deep temporal artery arises from the
temporodental trunk of the IMA in the deep
variant , as described before
-A branch of the anterior deep temporal artery
contributes to supply the lateral orbit ,
anastomosing with the lacrimal branch of OphA

c) Descending branches :
1-The inferior alveolar artery
2-Pterygoid branches
3-Buccal arteries
4-Masseteric branches

1-The inferior alveolar artery : (or inferior
dental artery)
-Arises from the inferior surface of the IMA ,
opposite the MMA origin (alone or with the
middle deep temporal artery)
-It traverses the mandibular canal to the
mental foramen where it gives the mental
artery which terminates in the midline
-It gives off dental branches and the
mylohyoid artery

2-Pterygoid branches :
-Which supply the pterygoid muscles
3-Buccal arteries :
-Which supply the buccinator muscle and
skin and mucosa of the cheek
4-Masseteric branches :
-Which supply the masseter muscle

d) Recurrent arteries :
1-The artery of the pterygoid canal or Vidian
artery
2-Pterygopalatine artery
3-Artery of the foramen rotundum

-Lateral 2D view following selective
external carotid artery injection ,
there is a direct hole fistula (arterial-
venous
fistula) between the accessory
meningeal artery and the posterior
aspect of the cavernous sinus
21 artery of the foramen rotundum
22 artery of the pterygoid canal
(vidian
artery)
m muscular branches
CS cavernous sinus
SOV superior ophthalmic vein
SMCV superficial middle cerebral
vein

1-The artery of the pterygoid canal or Vidian
artery :
-Arises from the IMA in the pterygopalatine fossa
and runs posteriorly around the sphenopalatine
ganglion (producing a small curve) and then
through the pterygoid canal to the nasopharynx
-It supplies mucosa of the superior portion of the
pharynx near the pharyngeal end of the
Eustachian tube and takes part in the
anastomosis around the tube
-Confusingly , the Vidian artery , with the same
territory of supply , can also arise from the
mandibulo-Vidian trunk of the petrous ICA
-It thus can arise from either ICA or IMA and serve
as an anastomosis between these arteries

2-Pterygopalatine artery :
-Arises close to the Vidian artery or with it as a
common trunk
-It is called the pterygovaginal artery by some
authors and pharyngeal branch of the internal
maxillary artery by others
-It passes through the pharyngeal canal (or
palatinovaginal canal) which connects the
pterygopalatine fossa and the nasopharynx
-It supplies mucosa of the pharyngeal roof and
around the Eustachian tube and reciprocates its
territory with the accessory meningeal and
pharyngeal branches of APA

3-Artery of the foramen rotundum :
-Passes backwards to supply the maxillary nerve
and adjacent skull base
-It runs above the level of the other recurrent
arteries and at its origin shows a small bend
-It accompanies the maxillary nerve (V2) with an
oblique posterosuperior trajectory on the lateral
angiogram and anastomoses with the anterior
branch of the ILT
-It thus forms a potential collateral route to the ICA

e) Anterior branches to the face :
1-The Posterior Superior Alveolar artery
2-The Infraorbital artery
3-The Descending Palatine arteries

1-The Posterior Superior Alveolar artery : (or
alveolar-antral artery)
-May arise directly from the IMA or as a common
trunk with the infraorbital artery , just after IMA
enters the pterygopalatine fossa
-It descends on the posterior surface of the maxilla
and runs anteriorly , to supply the maxillary sinus
, the molar and premolar teeth and the gums of
the upper alveolus

-Coned down lateral 2D
5 occipital artery
9 lingual artery
10 facial artery
fs foramen spinosum
m muscular branches
sphenopalatine
artery
artery

2-The Infraorbital artery :
-Passes through the infraorbital fissure , along the
infraorbital groove and canal to the infraorbital
foramen
-Before entering the canal , it gives branches to
the orbit (usually as a common trunk , the
inferomedial muscular artery) which supply the
lacrimal sac , nasolacrimal duct , extraocular
muscles and the lower eyelid
-After emerging from the infraorbital foramen , it
divides into numerous branches which supply
the inferior eyelid , the side of the nose , eyelid
and upper cheek

3-The Descending Palatine arteries : (or
greater palatine arteries)
-Run inferiorly and give off lesser palatine
arteries destined to supply the soft palate
posteriorly and the greater palatine artery
which runs forwards to supply the hard
palate and terminates in the nasal septum

f) Terminal branch (sphenopalatine artery) :
-The sphenopalatine artery is the terminal branch
of the IMA
-At the medial extent of its course in the
pterygopalatine fossa , the IMA enters the
sphenopalatine foramen and becomes the
sphenopalatine artery to supply the medial and
lateral walls of the nasal cavity and adjacent
paranasal sinuses

-The sphenopalatine artery gives a pharyngeal
branch and then divides within the nasal cavity
into lateral nasal and septal nasal arteries :
1-The Lateral Nasal artery :
-Divides into two main branches : the artery of the
middle concha and artery of the inferior concha
-They run forwards and downwards to supply the
mucosa of the conchae , the meatuses and the
maxillary sinuses

2-The Septal Nasal artery :
-Is longer than the lateral branches of the
sphenopalatine artery and supplies the nasal
septum and roof of the nasal cavity
-Together with branches of the artery of the middle
concha , these anastomose with the anterior and
posterior ethmoid arteries
-An inferior branch runs forwards on the septum to
the anterior palatine canal and anastomoses
with a branch of the descending palatine artery
to form the anterior palatine artery

- Frontal 2D
5 occipital artery
9 lingual artery
10 facial artery
18 posterior superior alveolar
artery
25 masseteric muscular
branches
fs foramen spinosum
m muscular branches
SB septal branches of

-Frontal 2D early arterial
5 occipital artery
9 lingual artery
10 facial artery
fs foramen spinosum
m muscular branches
artery
PDB posterior directed branches of
distal
internal maxillary artery. These are 1.
artery of foramen rotundum 2. artery
of the pterygoid canal (vidian artery),
and 3.
pharyngeal artery (pterygovaginal
artery)

-3D lateral
4 ascending pharyngeal artery
5 occipital artery
8 lingual-facial artery trunk
9 lingual artery
10 facial artery
fs foramen spinosum
artery

-3D Frontal
4 ascending pharyngeal artery
5 occipital artery
8 lingual-facial artery trunk
9 lingual artery
10 facial artery
fs foramen spinosum
artery

**N.B. Anastomoses with intracranial circulation:
-Numerous small anastomotic channels exist
between branches of the external carotid artery
and the intracranial circulation
-Branches of the middle meningeal artery , the
accessory meningeal artery and the artery of the
foramen rotundum normally anastomose with the
inferolateral trunk (artery of the inferior cavernous
sinus)
-These anastomotic channels can provide collateral
flow to the horizontal intracavernous segment of
the intracranial internal carotid artery

-They may also provide arterial supply to dural
arterial venous fistulas around the cavernous
sinus and skull base
-In addition these various arterial branches often
provide nutrient supply to the vasa nervorum of a
number of cranial nerves
-Careful attention to the presence of these
extracranial to intracranial communications , as
well as their importance in the integrity of multiple
cranial nerves , is mandatory when embolization
procedures are performed in the external carotid
artery territory

-Another important extracranial to intracranial
anastomotic channel is between the occipital
artery and the upper cervical vertebral artery
-This normal communication is not often readily
visible on routine angiographic studies
-Extreme caution must be exercised when
embolization involving the occipital artery is
undertaken to prevent potential inadvertent
embolization of the vertebral basilar
circulation

Anatomy of the external carotid artery (ECA)

Anatomy of the external carotid artery (ECA)

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Anatomy of the external carotid artery (ECA)