Anterior cerebral circulation with applied anatomy

1. ANTERIOR CEREBRAL
CIRCULATION
Dr.Mohammed Sadiq Azam
Postgraduate, Prof.Siraj’s unit, M:I
Deccan College of Medical Sciences

2. BRAIN - ANATOMY

3. BRAIN - ANATOMY

4. BRAIN - ANATOMY

5. ANTERIOR CIRCULATION
• Internal Carotid Artery - main
artery
• Terminates into :
• Anterior cerebral artery
• Middle cerebral artery
• Forms the crux of the anterior
circulation.

6. MIDDLE CEREBRAL ARTERY (MCA)

7. MIDDLE CEREBRAL ARTERY (MCA)
• Supplies most of the temporal lobe, anterolateral frontal lobe,
and parietal lobe.
• Perforating branches supply the posterior limb of the internal
capsule, part of the head and body of the caudate and globus
pallidus.
• Unilateral occlusion of Middle Cerebral Arteries at the stem
(proximal M1 segment) results in:
• Contralateral hemiplegia affecting face, arm, and leg (lesser).
• Homonymous hemianopia - Ipsilateral head/eye deviation.
• If on left: global aphasia.
• Usually occlusion is embolic in nature - thrombotic occlusion
more common in carotids.

8. MCA – (M 1) Horizontal segment
• Branch: Lateral lenticulostriate a
• Unilateral occlusion of
Proximal M1 Segment
results in deficits in:
• MOTOR
Contralateral Hemiplegia
(face and arm, lower extremity less affected.
• SENSORY
Homonoymous Hemianopia + Deviation of head/eyes toward the side of the
lesion.
• LANGUAGE
LEFT lesions: Global aphasia.
RIGHT lesions: Anosognosia.

9. MCA – (M 1) Lateral
lenticulostriate art.
• Branch of M1 Segment of MCA.
• Supplies basal ganglia structures:
• Part of head and body of caudate, globus pallidus, putamen,
and the posterior limb of the internal capsule.
Effect of lesion:
• Damage to the internal capsule resulting in contralateral
hemiparesis and sensory deficit.
• Speech may be affected (medial temporal lobe) as well as
visual function (Meyer's loop: optic radiations affected).

10. MCA – (M 2) Sylvian segment

11. MCA – (M 2) Sylvian segment
• Divides into superior and inferior divisions: can be a site for an embolus to
lodge.
• Branches supply:
Temporal Lobe and Insular Cortex (sensory language area of Wernicke)
Parietal Lobe
(Sensory cortical areas)
Inferolateral frontal lobe

12. MCA – (M 2) Sylvian segment
• Superior Division Infarction:
"Brachiofacial paralysis"
Sensorimotor deficit involving face and arm, leg to a lesser
extent. Foot is spared.
Ipsilateral deviation of head/eyes.
With Left lesion may have initial global aphasia -> motor
aphasia.
No impairment of alertness.
• Inferior Division Infarction:
Rarer than Superior Division Infarctions.
Superior quadrantanopia / homonymous hemianopia.
LEFT lesion: Wernicke aphasia (deficit in comprehension of
spoken/written language)
RIGHT lesion: Left-sided visual neglect.

13. MCA – (M 3) Cortical segment
• Distal branches of MCA course
laterally to insular cortex and
loop around operculum -
"Candelabra" effect seen on
lateral angiograms.
• Embolization of individual
cortical branches can produce
highly circumscribed infarctions
accompanied by specific
neurologic deficits.

14. ANTERIOR CEREBRAL ARTERY (ACA)

15. ANTERIOR CEREBRAL ARTERY (ACA)
• Supplies most of the medial surface of the cerebral cortex
(anterior three fourths), frontal pole (via cortical branches), and
anterior portions of the corpus callosum.
• Perforating branches (including the recurrent artery of Heubner
and Medial Lenticulostriate Arteries) supply the anterior limb of
the internal capsule, the inferior portions of head of the caudate
and anterior globus pallidus.

16. ANTERIOR CEREBRAL ARTERY (ACA)
• Bilateral occlusion of Anterior Cerebral Arteries at their stems results in
infarction of the anteromedial surface of the cerebral hemispheres:
• Paraplegia affecting lower extremities and sparing face/hands.
• Incontinence
• Abulic and motor aphasia
• Frontal lobe Symptoms: personality change, contralateral grasp
reflex.
• Unilateral occlusion (distal to Ant. Comm. origin) of Anterior Cerebral
Artery produces contralateral sensorimotor deficits mainly involving
the lower extremity with sparing of face and hands (think of the
humunculus)

17. ACA – A 1 SEGMENT
• From Internal Carotid Bifurcation to
Anterior Communicating Artery.
• A1 Branches:
Anterior Communicating Artery
(connects both sides of anterior
circulations).
Medial Lenticulostriate Arteries(supply
basal ganglia, anterior limb of internal
capsule).
Recurrent Artery of Heubner(supplies
head of caudate and anteroinferior
internal capsule)

18. ACA – Anterior communicating art
• Connects bilateral anterior
circulations.
Common location for cerebral
aneurysms.

19. ACA – Recurrent artery of Heubner
• Supplies head of caudate
and anteroinferior
internal capsule.

20. ACA – Pericallosal artery
• Continuation of the
Anterior Cerebral Artery
as it arches superiorly
and posteriorly.
Supplies the medial
surface of the cerebral
hemispheres and corpus
callosum.

21. ANTERIOR CHOROIDAL ARTERY
Arises from ICA (rarely from MCA also)
The anterior choroidal artery serves many structures in the
cerebrum:
• choroid plexus of the lateral ventricle and third ventricle
• optic chiasm and optic tract
• internal capsule
• lateral geniculate body
• globus pallidus
• tail of the caudate nucleus, hippocampus, amygdala
• substantia nigra
• red nucleus
• crus cerebri

22. ANTERIOR CHOROIDAL ARTERY
Lesions lead to:
Contralateral hemiplegia
Contralaterial hemi-hypoaesthesia
Homonymous hemianopsia
Due to ischemic involvement of:
Internal capsule
Thalamus
Optic chiasm/Optic tract

23. CIRCLE OF WILLIS
• Communication between the anterior and posterior circulations

24. WATERSHED AREAS

25. WATERSHED AREAS
There are two patterns of border zone infarcts:
Cortical border zone infarctions:
Infarctions of the cortex and adjacent subcortical white matter located at the
border zone of ACA/MCA and MCA/PCA
Internal border zone infarctions
Infarctions of the deep white matter of the centrum semi-ovale and corona
radiata at the border zone between lenticulostriate perforators and the deep
penetrating cortical branches of the MCA or at the border zone of deep white
matter branches of the MCA and the ACA

26. THANK YOU