Circulus arteriosus major

Circulus Arteriosus Major

File:Circulus arteriosus major.jpg

Circulus arteriosus major

The Circulus arteriosus major (also known as the Circle of Willis) is a circular anastomosis at the base of the brain that connects the internal carotid and vertebral artery systems. It is named after Thomas Willis, an English physician who first described it in the 17th century.

Anatomy

The Circle of Willis is formed by the anastomosis of several arteries: the anterior cerebral artery, the anterior communicating artery, the internal carotid artery, the posterior cerebral artery, the posterior communicating artery, and the middle cerebral artery. These arteries supply blood to over 80% of the cerebrum.

Function

The primary function of the Circle of Willis is to provide collateral circulation to the brain. This means that if one of the main arteries supplying blood to the brain is blocked, the Circle of Willis can provide an alternative route for blood flow, thus preventing a stroke.

Clinical Significance

Abnormalities in the Circle of Willis, such as aneurysms or congenital malformations, can lead to serious conditions like subarachnoid hemorrhage, ischemic stroke, or brain aneurysm. Therefore, understanding the anatomy and function of the Circle of Willis is crucial in the diagnosis and treatment of these conditions.

See Also

• Cerebral circulation
• Carotid artery
• Vertebral artery