Blood Supply of the Head, Neck and Brain

7/23/2019 Blood Supply of the Head, Neck and Brain

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Blood supply of head and

neck & brain

Dr. Narendra Pamidi


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Learning objectives

Objectives:

After having attending this lecture and studied the lecture

notes, students should have learned:

the arteries that supply blood to the head and neckthe territories of the external and internal carotids and

their anastomosis

blood supply of the scalp

the major neurovascular bundles in the neck

how the spinal cord is supplied with arterial blood

the venous drainage of the brain and spinal cord


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Common carotid artery (CCA)

Origin:

Right CCA: branch

of brachiocephalic

trunk begins in neck

behind rightsternoclavicular joint

Left CCA branch of

aortic arch begins in

thorax & passes

behind left

sternoclavicular joint


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Common carotid

artery

Course

Runs in carotid sheath

along with Internal

jugular vein & vagus

nervePasses upwards &

backwards in the neck,

From sternoclavicularjoint to upper border of

thyroid cartilage

Ends by dividing into

ECA & ICA arteries


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Common carotid artery

Special Features

Carotid sinus localised dilatation atterminal part of CCA (or beginning

of ICA) innervated byglossopharyngeal & sympathetic

nerves act as baroreceptortoregulate blood pressure. carotid sinussyndrome

Carotid body small reddish-brownstructure situated behind

bifurcation of CCA innervatedmainly by glossopharyngeal n erveacts as chemoreceptorie. respondto changes in concentration of O2

& CO2 in blood


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Deep fascia of theneck

1. Investing fascia

2. Prevertebral

3. Carotid sheath

4.Pretracheal


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External carotid artery (ECA)The ECA is one of the 2

terminal branches of theCCA

It is the chief artery ofsupply to structures in theneck & face

Origin: begins in carotidtriangle of neck

At level of upper border ofthyroid cartilage ( betweenCV3 & 4)


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External carotid artery

Course runs upwards, slightly

backwards & laterally

enters substance of parotid

gland terminates behind neck of

mandible by dividing into

the maxillary & superficial

temporal arteriesNote: at first it lies medial to

ICA and then passes

backwards & laterally to lie

lateral to ICA


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External carotid artery - Branches

There are 8 branches1. Superior thyroid

2. Ascending pharyngeal

3. Lingual

4. Facial5. Occipital

6. Posterior auricular

7. Superficial temporal

8. Maxillary

Sister Lilly powdered face

often attracts medical students


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Maxillary artery

The maxillary artery

has an extensive

distribution to the

upper & lower jaws,

muscles of mastication,the palate & the nose

Origin: It is the larger

terminal branch of

ECA

arises in parotid gland

behind neck of

mandible


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Infra-temporal fossa


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Maxillary artery


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1stpart:

Deep auricular

Anterior tympanic

Middle meningeal

Accessory meningealInferior alveolar

2ndpart: Branches to

muscles of mastication

3rdpart:

Posterior superior

alveolar A

Infra orbital A

Greater palatine APharyngeal A

Artery of pterygoid canal

Spheno palatine A


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Circle of Willis-Vertebral-basilar system


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Each cerebral

artery givestwo types of

branches:

Central

(striate) andcortical

branches


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Medial

surface

Majority of it

bymiddle

cerebral

artery


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Medial surface

Most of itanterior

cerebral artery

Occipital lobeposteriorcerebral artery

Temporal polemiddle

cerebral artery


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Inferior surface

Lateral part of orbital

surface and temporal pole

middle cerebral artery

Medial part of orbital

surfaceanterior cerebral

artery

Tentorial surface behind

the temporal pole

posterior cerebral artery


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Subclavian artery - Course

Subclavian artery is dividedinto 3 parts by the presenceof the scalenus anteiormuscle

1st Part - arches upwards &laterally from behind

sternoclavicular joint tomedial border of scalenusanterior

2nd Part - lies behindscalenus anterior muscle

3rd Part - extends from lateralborder of scalenus anterior toouter border of 1st rib

where it continues as axillary

artery?


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Subclavian artery Branches

1st Part:

1. Vertebral artery2. Internal thoracic artery

3. Thyrocervical trunk gives off3 branches

a) inferior thyroid, b) transversecervical c) suprascapular

2nd Part:

1. Costocervical trunk gives off 2branches (Superior intercostalartery, deep cervical artery)

3rd Part:

Descending (dorsal) scapular

artery


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Clinical anatomy of subclavian artery

1. 3rd part may be compressed against

1st rib to stop bleeding in upper arm2. Aneurysmsmay form in 3rd part of

artery. Exert pressure on brachial

plexus & results in pain, weakness &

numbness in upper limb

3. Cervical rib artery is kinked as it

passes over rib, causing occlusion

4. Subclavian steal syndrome (SSS):

Occlusion of SA. Blood flow to the

upper limb via vertebral or internal

thoracic. Blood supply from the

brain/thorax to the upper

extremities in SSS is considered to

be stolen


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Internal carotid

artery-brain

Enters the brain- carotid

canal

Passes through cavernous

sinus

Branches: Ophthalmic A

Terminal branches: anterior

and posterior cerebral

arteries

Joins with posterior cerebral

arteries to form Circle of

Willis at the base of brain


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Venous drainage


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Internal jugular veinsThe IJV drains the brain, neck

& face

Origin: begins at jugularforamen at base of skull

it is a continuation of the

sigmoid sinusCourse: descends in carotid

sheath

passes downwards &

anteriorlyends behind medial end of

clavicle by joining withsubclavian vein to form

brachiocephalic vein


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Internal jugular veins - Tributaries

inferior petrosal sinus

facial vein lingual vein

pharyngeal veins

superior thyroid vein

middle thyroid veinsometimes, occipital vein

Note: Thoracic duct opens

into angle of union betweenleft IJV & Left subclavian vein


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Internal jugular veins

Clinical NotesIn congestive heart failure or any

disease where venous pressure israised, the IJV is markedly

dilated, engorged

Deep cervical lymph nodes liealong the IJV. In malignancies

involving these nodes, the vein isusually removed together withthe nodes in a surgical procedurecalled block dissection of the

cervical nodes


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External jugular vein


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Lymphatics

Superficial

Collor &

Deep Column


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Superficial

Sub mental (Below chin)Submandibular

Parotid

Mastoid

Occipital (back of skull)

Deep

I. Jugulo-digastric

II. Jugulo-

omohyoid


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Good day & Thank you

ReferencesEssential Clinical Anatomy: Keith L. More, 4th edition Atlas

of Human Anatomy: Frank H. Netter http:/

Greys anatomy: The anatomical basis of clinical practice

Blood Supply of the Head, Neck and Brain

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