Cerebral arterial circle

Circle of Willis

1. Cerebral arterial circle Presented by : vivek

2. There are two paired arteries which are responsible for the blood supply to the brain: The  vertebral arteries The   internal carotid arteries. These arteries arise in the neck, and ascends to the cranium. Within the cranial vault the terminal branches of the arteries forms an anastomotic circle, called “Cerebral arterial circle”.

3. Internal carotid artery Vertebral artery

4. Also referred to as: The Circle of Willis The Loop of Willis The Willis polygon The Circle of Willis is a ring-like arterial structure located at the base of the brain that supplies blood to the brain and surrounding structures.

5. There are three main (paired) constituents of the Circle of Willis: Anterior cerebral arteries   – terminal branches of the internal carotid arteries. Internal carotid arteries   – located immediately proximal to the origin of the middle cerebral arteries. Posterior cerebral arteries   – terminal branches of the vertebral arteries.

6. To complete the circle, two ‘connecting vessels’ are also present: Anterior communicating artery   – connects the two anterior cerebral arteries. Posterior communicating artery   – branch of the internal carotid, this artery connects the ICA to the posterior cerebral artery.

7. Circle of Willis Anterior communicating artery Posterior communicating artery Anterior cerebral artery Internal carotid arteries Posterior cerebral arteries

8. Functions of Circle of Willis The Circle of Willis is basically an arrangement of interconnected vascular channels that ensure that the (oxygenated) blood flow to the brain continues unimpeded, in case any of the principal suppliers are obstructed by injury, physical pressure or disease.

9. Intracerebral Aneurysms An  aneurysm  is a dilation of an artery, which is greater than 50% of the normal diameter. They are most likely to occur to occur in the vessels contributing to the  Circle of Willis . They are particularly dangerous – producing few symptoms until they  rupture . Upon rupture, blood typically accumulates in the subarachnoid space – with a subsequent increase in intracranial pressure. Treatment: Surgical

10. Thankyou For your kind attention