Arterial Supply of the Brain

Arterial Supply of the Brain

Overview of Arterial Supply

  • The brain receives blood supply from two primary pairs of arteries:
  • Internal Carotid Artery (ICA) (2)
    • Entry into the cranium: (specific entry point not provided)
  • Vertebral Artery (VA) (2)
    • Entry into the cranium: (specific entry point not provided)

Anatomy and Relations of Arteries

  • The vertebral arteries converge to form the Basilar Artery on the ventral surface of the brainstem.
  • Major arteries lie within the subarachnoid space, facilitating the supply of blood to various brain regions.

Circle of Willis

  • The major arteries that contribute to the Circle of Willis include:
  • Internal Carotid Arteries
    • Supply blood to the cerebral hemispheres.
    • Branches:
    • Anterior Cerebral Artery (ACA) – Supplies anterior portions of the brain.
    • Middle Cerebral Artery (MCA) – Supplies lateral surfaces of the brain.
  • Vertebral Arteries
    • Join to form the Basilar Artery.
  • Posterior Cerebral Arteries (PCA) – Supply the posterior aspect of the brain.

Areas of Supply

  • The primary arteries and their corresponding areas of supply include:
  • Anterior Cerebral Artery (ACA): Supplies medial aspects of the frontal lobes and superior medial parietal lobes.
  • Middle Cerebral Artery (MCA): Supplies lateral aspects of the cerebral hemispheres.
  • Posterior Cerebral Artery (PCA): Supplies the occipital lobe and the inferior parts of the temporal lobe.

Types of Arteries: Cortical vs. Penetrating

  • Cortical Arteries:
  • Larger arteries that primarily supply the cortex (e.g., ACA, MCA, PCA).
  • They anastomose with other cortical arteries to ensure collateral circulation.
  • Penetrating Arteries:
  • Smaller arteries that branch from the Circle of Willis or from cortical arteries.
  • They penetrate the ventral surface of the brain to supply deeper structures, referred to as anatomical end arteries.

Key Terminology

  • Cortical Arteries: Large vessels supplying the outer layer of the brain.
  • Penetrating Arteries: Smaller vessels supplying deeper brain structures, essential for proper brain function.

Additional Notes

  • Access to arterial supply is crucial for understanding both normal brain function and pathology.
  • Sources:
  • Moore et al., chapter 7 for anatomical references.
  • Snell, chapter 17 for definitions of cortical and penetrating arteries.