41. Blood supply of the brain.

BLOOD SUPPLY OF THE BRAIN

• Subclavian artery
• Common Carotid art.
• Internal
• opthalmic art.
• Post. communicating
• Ant. chorodial
• Ant. Cerebral (ACA)
• ACA
• Ant. communicating art.
• Middle cerebral (MCA)
• External
• Thyrocervical Trunk
• Costocervical
• Vertebral art.
• Ant. Spinal
• Post. spinal
• Medullary branches
• Post. Inferior cerebellar
• Meningeal branches
• + Vertebral art. → Basilar art.
• Post. Cerebral (PCA)
• Labyrinthine
• Pontine branches
• Ant. Inf cerebellar
• Superior cerebellar

• Atrial supply of the brain depends on 2 aterial systems ( carotid & vertebro - basilar) Both systems anastomose at the Circle of Wills.

Carotid:

• The carotid system includes both internal carotid arteries (ICA).
• ICA begins at upper border of thyroid cartilage (bifurcation of common carotid artery).
• It has 4 parts and runs in 4 anatomical areas (1ˢᵗ: cervical, 2ⁿᵈ: petrous, 3ʳᵈ: cavernous, and 4ᵗʰ: cerebral).
• It ends at anterior perforated substance by giving anterior cerebral artery (ACA) and middle cerebral artery (MCA).

Cerebral arteries:

1) Anterior cerebral artery

• Begins: as one of the 2 terminal branches of internal carotid artery.
• It runs forwards towards the longitudinal fissure.
• It communicates with its fellow through anterior communicating artery.
• It curves backwards over the corpus callosum.
• Ends: by anastomosing with posterior cerebral artery at the parieto-occipital sulcus.
• Branches: mainly to the medial surface of the cerebral hemisphere.
• Cortical branches:
• All medial surface except occipital lobe.
• One inch strip superiorly on lateral surface.
• Medial aspect of orbital part of inferior surface.
• Central branches:
• Anteromedial set of branches: pierce anterior perforated substance to supply basal nuclei (anterior part of caudate and lentiform), and internal capsule (genu and lower ½ of anterior limb).