Vascular territory of brain

To understand vascular supply of brain we can divide it into supratentorial and infratentorial parenchyma.

Supra tentorium composed of cerebral hemispheres on either side of mid line and deep grey nuclei at the core.

Cerebral hemispheres has frontal lobes anteriorly, occipital lobes posteriorly, parietal lobes cranially, temporal lobes caudally. The frontal lobe can be divided into medial or para sagittal portion and lateral portion, temporal lobes divided into medial and lateral portions. Occipital lobes divided into medial and lateral portions.

Deep grey nuclei at the core consist of bilateral Basal ganglia anteriorly, which in turn composed of caudate and lentiform nuclei and thalami posteriorly on either side of third ventricle. 

Infra tentorium composed of cerebellum and brain stem.

Cerebellar hemispheres divided into cranial and caudal portion. The caudal portion divided further into major posterior portion and smaller anterior portion.

Brain stem which is composed of mid brain, Pons and medulla.

ACA, MCA and PCA give cortical branches to cerebral hemispheres.

Para sagittal frontal lobe and cingulate gyri - cortical  ACA territory.

Medial occipital and medial temporal lobes - cortical PCA territory.

The remaining major lateral portions of cerebral hemispheres, the perisylvian cerebral cortex – cortical MCA territory, some further divide it into superior division territory which is the portion anterior and cranial to sylvian fissure and inferior division territory which is the portion caudal and posterior to sylvain fissure.

ACA, MCA and PCAs, their proximal most portions gives perforator branches to the deep grey nuclei at the core.

ACA a1 segment gives medial lenticulostriate perforators and MCA m1 segment gives lateral lenticulo striate which supply basal ganglia. PCA p1 segment gives thalamostriate perforators which supply thalami and mesencephalic mid brain.

Pica, intra cranial branch from each vertebral supply major posterior part of caudal portion of cerebellum on either side and medulla.
Vertebral join to form Basilar.

Aica, from proximal portion of basilar supply the remaining small anterior part of caudal portion of cerebellum on either side.

Superior cerebellars, from distal most portion of basilar supply the cranial portion of cerebellar hemispheres on either side.

Basillar gives Pontine perforators on either side supply Pons.

Between cortical branches of ACA, MCA and PCA we have cortical border zone. Anterior cortical border zone between ACA-MCA and posterior cortical border zone between MCA and PCA.

Between cortical branches and deep branches (perforators) we have deep (internal) border zone.