The cerebrum II

The blood supply of the brain Arteries of the brain : 2 internal carotid arteries & 2 vertebral arteries Internal carotid art...

The blood supply of the brain

Arteries of the brain : 2 internal carotid arteries & 2 vertebral arteries

	Internal carotid arteries	Vertebral arteries
Course	Begins at the bifurcation of the common carotid artery (There it possess a local dilatation – Carotid sinus) Ascends the neck & perforates the base of the skull by passing through the carotid canal of the temporal bone Then it runs horizontally forward through the cavernous sinus & emerges on the medial side of the anterior clinoid process by perforating the dura mater Then it enters the subarachnoid space by piercing the arachnoid mater & turns posteriorly to the region of the medial end of the lateral cerebral sulcus There it divides into anterior & middle cerebral arteries	A branch of the 1st part of the subclavian artery Ascends the neck by passing through the foramina in the transverse processes of the upper 6 cervical vertebrae Enters the skull through foramen magnum & enter the subarachnoid space Then it passes upwards, forward & medially on the medulla At the lower border of the pons, it joins the vessels of the opposite side to form the basilar artery
Branches of the cranial part	Ophthalmic artery Posterior communicating artery Choroidal artery Anterior cerebral artery (ACA) The smaller terminal branch Joined to the ACA of the opposite side by the anterior communicating artery Supply the ‘leg area’ of the precentral gyrus Middle cerebral artery (MCA) The largest branch of the ICA             Supply all the motor areas except ‘leg area’	Meningeal branches Posterior spinal artery Anterior spinal artery Posterior inferior cerebellar artery (Largest branch of the vertebral artery) Medullary arteries

Basilar artery

• It’s formed by the union of 2 vertebral arteries
• Ascends in a groove on the anterior surface of the pons
• At the upper border of the pons, it’s divided into 2 posterior cerebral arteries
• Branches
  
  
  
  1. Pontine arteries
  2. Labyrinthine arteries
  3. Anterior inferior cerebellar arteries
  4. Superior cerebellar artery
  5. Posterior cerebral artery : Supplies the visual cortex
  
  

The circle of Willis

1. It lies in the inter peduncular fossa at the base of the brain
2. It’s formed by the anastomosis between the 2 internal carotid & 2 vertebral arteries
3. It allows blood that enters by either internal carotid or vertebral arteries to be distributed to any part of both cerebral hemispheres
4. Cortical & central branches arise from the COW & supply the brain substance

Areas supplied by the cerebral arteries



 
Arteries to specific brain areas
 
Arterial supply of the deep cerebral structures from the middle cerebral artery

Corpus striatum & internal capsule	Medial & lateral striate central branches the middle cerebral artery Central branches of the anterior cerebral artery
Thalamus	Posterior communicating  artery Posterior cerebral artery Basilar artery
Midbrain	Posterior cerebral artery Superior cerebellar artery Basilar artery
Pons	Anterior, inferior & superior cerebellar arteries Basilar artery
Medulla	Vertebral artery Anterior & posterior spinal artery Posterior inferior cerebellar artery Basilar artery
Cerebellum	Superior cerebellar artery Anterior inferior cerebellar artery Posterior inferior cerebellar artery

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