Blood supply to Brain

Hypertension affects deep branches of cerebral artery----> causes Lacunar infarct------> affect Basal Ganglia, Internal Capsule (paralysis), Subthalamus(Hemiballismus)..

Hypotension affects watershed area causing watershed Infarct. area lies between ACA and MCA on lateral aspect of cerebral hemisphere.  Affect pre and Post central gyrus----affect trunk area 'Men in barrel syndrome'  means UL---normal function, LL-Normal function but Trunk is affectted both sensory and motor part.

MCA: Supplies contralateral UL, Neck and face, both sensory and motor part.

ACA: Supplies contralateral Pelvis and LL, both sensory and Motor part.

PCA: Supplies Occipital Lobe

So occlusion of 

MCA: Contralateral spastic paresis and anesthesia of UL, Neck and Face.

ACA: Contralateral spastic paresis and anesthesia of LL and Pelvis.

PCA: Contralateral homonymous Hemianopia with macular sparing.

Other findings:

Left MCA: 

• aphasia- broca's, Wernicke, Conduction.
• Angular Gyrus: Gesterman Syndrome

Right MCA:

• Inferior parietal Lobule: Unilateral neglect of Left side of body

Lacunar Stroke VS Major Cerebral Artery Stroke:

Lacunar stroke affects all UL, LL and face altogether while Major cerebral Artery affect different aprt of the body like UL, face   vs   LL.  

Internal Capsule Infarct:

It has Ant limb, genu and Posterior limb.

Ant Limb: contains Talamo-mammilary tr---not significant sign and symptoms

genu: contains coricobulbar tr ----- affects entire Lower Face.

Post Limb: contains all 3 major tracts: CST, Talamocortical Tr and Spinothalamic tr --- cause contralateral spastic paralysis, contralateral loss of touch, pain and temerature sensation.

Here are Some really good images showing blood supply to different part of the brain....







Brain stem arteries - anterior view 

1. Posterior cerebral artery
2. Superior cerebellar artery
3. Pontine branches of the basilar artery
4. Anterior inferior cerebellar artery
5. Internal auditory artery
6. Vertebral artery
7. Posterior inferior cerebellar artery
8. Anterior spinal artery
9. Basilar artery