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BRAIN’S ARTERIAL
SUPPLY
Fundamentals Principles
• brain comprises around 2% of total body weight
• brain has a relatively high metabolic demand, due to being largely
reliant on oxidative metabolism, so it receives 15-20% of the total
cardiac output
...
Arterial Blood Supply to the Brain
• Arterial blood supply to the brain can be divided into:
the anterior & posterior circulation
...
• Anterior Circulation comprises of
• Internal Carotid Arteries
• Course and branches
• The left and right common carotid arteries bifurcate at the level of C3/C4 to give off
the internal carotid arteries (ICA) within the carotid sheath
...
• Once in the cranial cavity, the internal carotid arteries pass anteriorly through the cavernous sinus
...
Ophthalmic artery: Supplies all the structures in the orbit as well as some structures in the nose, face and
meninges
...
Posterior communicating artery:
Anteriorly connects to the internal carotid artery prior to the terminal bifurcation of the ICA into
the anterior cerebral artery and middle cerebral artery
...
3
...
4
...
The middle cerebral arteries
supply the lateral cerebral cortex, in addition to the anterior temporal lobes and the insular cortices
...
• The vertebral arteries then proceed to enter the transverse foramina of the spine at level C6 and
continue superiorly
...
• Once inside the cranial vault, the vertebral arteries give off the following branches:
1
...
Anterior and posterior meningeal arteries – supply the dura mater
3
...
posterior spinal arteries – supply the spinal cord along its entire length (dorsal spinal cord to conus
medullaris)
• The vertebral arteries then converge to form the basilar artery at the base of the pons, inside the
cranium
...
• Caudal to rostral branches;
1
...
Labyrinthine artery (Internal Acoustic Artery)
3
...
Superior cerebellar artery
• The basilar artery eventually anastomoses
With the circle of Willis via the posterior
cerebral arteries and
posterior communicating arteries
Clinical relevance: Locked-in syndrome
Pontine infarcts cause an interruption in the
myriad of neuronal pathways enabling
communication between the cerebrum,
cerebellum and spinal cord
...
Individuals suffering from
damage to the pons
are fully conscious and cognitively intact
...
3 Main Paired parts of Circle of Willis
• Anterior Cerebral Arteries -Terminal branch of ICA)
supplies Primary Motor , Primary Somatosensory Cortex
Middle portion of cerebral cortex
• Internal Carotid Artery -Located immediately proximal to Origin of Middle
Cerebral Artery
...
• Posterior Cerebral Arteries -Terminal branches of Vertebral arteries
supplies Occipital Lobe
Picks up visual field for Contralateral and Ipsilateral sides
To Complete Circle, two communicating vessels are;
• Anterior Communicating Artery Connects two Anterior Cerebral Arteries
• Posterior Communicating Artery Connects ICA to Posterior Cerebral Artery
• Clinical relevance: Aneurysms
• Saccular or ‘berry‘, aneurysms occur most
frequently within the circle of Willis vasculature
and are the most common cause of nontraumatic subarachnoid haemorrhage
...
THANK YOU