الفهرس 
Anatomy of cerebral anterior circulationOnly 14 pages are availabe for public view
 |  | from | 185 |  |  |
| | | from | 185 | | |
Abstract
Most of the brain is supplied by the two internal carotid arteries and the central anastomosis between them, called the circle of Willis. Anteriorly the anterior cerebral arteries are joined by the anterior communicating artery. Posteriorly the basilar artery divides and originates the two cerebral arteries, and each artery is joined to the ipsilateral internal carotid by a posterior communication artery. (Bell RS. et al,2008 ) The cerebral anterior circulation is the anterior part of circe of Willi’s and includes the supraclinoidal portion of the internal carotid artery (ICA) and its ophthalmic ,anterior choroidal , posterior communicating ,anterior cerebral and middle cerebral arteries . ( Rhoton AL Jr , 2002 ). Unlike other subcategories of stroke, the incidence of SAH has not decreased over time. The incidence of SAH worldwide varies widely (2-49 cases per 100,000 population) . Of these cases, 80% are caused by aneurysmal subarachnoid hemorrhage., with the highest rates occurring in Japan and Finland. (Gershon A et al , 2009 ). Aneurysms commonly arise at the bifurcations of major arteries. Most saccular aneurysms arise on the circle of Willis or the middle cerebral artery (MCA) bifurcation Approximately 86.5% of all intracranial aneurysms arise on the anterior (carotid) circulation. Common locations include the anterior communicating artery (30-40%), the internal carotid artery (ICA) at the posterior communicating artery