V. Learning unit: Large hemispheric infarction caused by

                         ipsilateral internal carotid artery thrombosis

Objectives and competencies

This syllabus introduces clinico-pathological relevancies of acute and chronic-stage stroke and consequent cerebral softening in multidisciplinary approach. The anatomical chapter introduces basic structure of intracranial blood supply, branches of anterior (carotid) and posterior (vertebrobasilar) cerebral circulation, vessels of the circle of Willis, territorial blood supply of the brain and persisting embryonic arteries. The pathological chapter describes circulatory insufficiencies (cerebral hypoxia, ischemia) and resulting acute and chronic stage stroke, brain infarction, white matter hypoxia/ischemia, spinal infarction, and various clinical forms of intracranial vascular diseases. Students may learn general radiological characteristics of stroke on CT and MR imaging and pathophysiological background of various radiological signal changes. The clinical chapter introduces epidemiology, etiology, risk factors, symptomatology, clinical course, diagnosis, non-imaging diagnostic modalities, differential diagnosis and treatment modalities of stroke in multimedia enhanced environment with illustrations photos and tables.

V./1. chapter: Circulatory system of the brain

                                                              Gabor Baksa

V./1.1.: Introduction

V./1.1.1. Basic anatomy of the cerebral circulation

The cerebral blood supply is derived from the two pairs of arterial trunks, which passes through the base of the skull, the right and left internal carotid arteries and the vertebral arteries. Based on their anatomical location the terms

• - anterior or carotid and

• - posterior or vertebrobasilar cerebral circulations are used. . In most cases these two circulatory systems are multiply interconnected, forming an arterial anastomosis at the base of the brain known as the  arterial circle of Willis.

V./1.1.2.: Anatomical variants 

The arterial circle of Willis is frequently poorly developed, aplastic or hypoplastic arteries can appear with the compensation of the contalateral, well-developed arterial trunks.

Also artery duplications or in rare occasions triplications are typical malformations of this circle. In particular arteries fenestration can occur, which refers to a segmental duplication, where the previous and following segments of the arteries are forming a united trunk.

Unordinary origins of the cerebral arteries are seen with different prevalence rate in the particular artery. Rarely so-called persistent arteries are observed, which are developed during ontogenesis and destined to disappear during fetal life.

Note that there are also many other anastomotic connections at the base of the skull among the arteries deriving from the external carotid arteries supplying the meninges and between the arteries supplying the brain.

The chapter structure

• V./1.1.: Introduction

  • V./1.1.1. Basic anatomy of the cerebral circulation

  • V./1.1.2.: Anatomical variants

• V./1.2.: Anterior cerebral circulation

  • V./1.2.1.: Internal carotid artery (ICA)

  • V./1.2.2.: The segments of internal carotid artery used in clinical practice

  • V./1.2.3.: Interdural branches of the internal and external carotid artery

    • V./1.2.3.1.: Ascending pharyngeal artery and middle meningeal artery 

    • V./1.2.3.2.: Caroticotympanic arteries and artery of the pterygoid canal (Vidian artery)

    • V./1.2.3.3.: Branches of the intracavernous segment

  • V./1.2.4.: Intradural branches of the internal carotid artery

    • V./1.2.4.1.: Ophthalmic artery (OA)

    • V./1.2.4.2.: Superior hypophyseal artery

    • V./1.2.4.3.: Posterior communicating artery (Pcomm, PCOM)

    • V./1.2.4.4.: Anterior choroidal artery

    • V./1.2.4.5.: Anterior cerebral artery (ACA)

      • V./1.2.4.5.1.: Pre-communicating or A1 segment (proximal ACA)

      • V./1.2.4.5.2.: Post-communicating or A2-szegment (distal ACA)

    • V./1.2.4.6.: Anterior communicating artery (AcommA, ACOM, ACoA)

    • V./1.2.4.7.: Middle cerebral artery (MCA)

      • V./1.2.4.7.1. Sphenoidal or M1 segment

      • V./1.2.4.7.2.: Insular or M2 segment

      • V./1.2.4.7.3.: Opercular or M3 segment

      • V./1.2.4.7.4.: Terminal, cortical or M4 segment

• V./1.3.: Posterior or vertebrobasilar cerebral circulation

  • V./1.3.1.: Vertebral arteries

  • V./1.3.2.: Main arteries and their supplied regions of the vertebral arteries (posterior cerebral circulation)

    • V./1.3.2.1.: Anterior spinal artery

    • V./1.3.2.2.: Posterior spinal arteries

    • V./1.3.2.3.: Posterior inferior cerebellar artery (PICA)

    • V./1.3.2.4.: Basilar artery (BA) 

      • V./1.3.2.4.1.: The pontine rami

      • V./1.3.2.4.2.: Anterior inferior cerebellar artery (AICA)

      • V./1.3.2.4.3.: Superior cerebellar artery (SCA)

      • V./1.3.2.4.4.: Posterior cerebral artery (PCA)

• V./1.4.: Arterial Circle of Willis

• V./1.5.: Territorial organization of the circulation of the brain

• V./1.6.: Persistent fetal arteries (persistent caroticobasilar anastomoses)

Refereces

Bähr, Frotscher: Duus’ Neurologisch-topische Diagnostik. Georg Thieme Verlag 2003.

Hajdu: Vezérfonal a neuroanatómiához. Semmelweis Kiadó 2004.

Szirmai: Neurológia. Medicina 2005.

Huber: Cerebral angiography. Georg Thieme Verlag 1982.

Yasargil: Microneurosurgery. Georg Thieme Verlag 1984.