Anatomy of cerebral Arteries College of Medicine/ Al- Kufa University By Maher Finjan Taher M.SC. Human anatomy College of Medicine/ Al- Kufa University

Contents Introduction. Internal carotid artery. Vertebral artery. Basilar artery. Circle of Willis (Circulus Arteroisus). Anatomic variation of circle of Willis.

Introduction Brain is supplied by : Two internal carotid arteries. Two vertebral arteries. The four arteries lie within subarachnoid space, and their branches anastomose on the inferior surface of brain to form circle of Willis.

Internal carotid artery Subdivided into four parts: Cervical . Petrous. Cavernous. Cerebral.

Cervical part: Begin at bifurcation of common carotid artery & ascend the neck. Has no branches in the neck. Petrous part: When perforates the base of skull through carotid canal of temporal bone. The branches: Vidian artery or artery of pterygoid canal. Caroticotympanic artery.

Cavernous part: Pass through the cavernous sinus. Branches : Meningohypophyseal artery. Inferolateral trunk.

Cerebral part: In region of medial end of lateral cerebral sulcus Cerebral part: In region of medial end of lateral cerebral sulcus. Branches : Ophthalmic artery. Posterior communicating artery. Anterior choroidal artery. Anterior cerebral artery. Middle cerebral artery.

Circle of Willis & its branches

Vertebral artery Branch of first part of subclavian artery. Cervical part: Pass through foramina in the transverse processes of upper six cervical vertebrae, then enters the skull through the foramen magnum.

Vertebral artery as indicated by arrows

Cranial part of vertebral artery: It enters skull through foramen magnum & pierces dura mater & arachnoid to enter subarachnoid space. It then passes upward, forward, and medially on medulla oblongata. Branches: Meningeal branches. Posterior spinal. Anterior spinal artery. Posterior inferior cerebellar artery. Medulary arteries.

Basilar artery Formed by union of the two vertebral arteries on the groove on the anterior surface of pons. Branches: Pontine arteries. Labyrinthine artery. Anterior inferior cerebellar artery. Superior cerebellar artery. Posterior cerebral artery.

Circle of Willis Two internal carotid arteries. Two vertebral arteries. Anterior communicating artery. Anterior cerebral arteries. Posterior communicating arteries. Basilar artery.

Circle of Willis

Anatomic variation of circle of Willis Proximal part of posterior cerebral artery is narrow & its ipsilateral posterior communicating artery is large. Anterior communicating artery is large so single internal carotid supplies both anterior cerebral arteries.

References Bouthillier, Alain E. 1998. Quising RG, Rhoton AL Jr. 2003. Rhoton AL Jr., Fujiik, Fradd B. 2000. Morandix. 2006. Richard S. Snell. 2006. Keth L. Moore, Arthur F. Dally, Anne M.R. Agur. 2008. Gibo H, Carver CC. 1997.

Thanks for listening