Blood Supply of the Brain Quiz

Blood Supply of the Brain

• The brain receives its blood supply from two sets of arteries:
  • Vertebral arteries
  • Internal carotid arteries

Arterial Supply of the Brain

• Vertebral arteries:
  • Originate from the first part of the subclavian artery at the root of the neck.
  • Travel through the foramen magnum.
  • Ascend the brainstem, uniting at the lower border of the pons to form the basilar artery.
• Internal carotid arteries:
  • Branch from the common carotid arteries.
  • Enter the skull via the carotid canal.
  • Pass through the cavernous sinus.
  • Terminate at the base of the brain, dividing into two terminal branches:
    • Anterior cerebral arteries
    • Middle cerebral arteries

Internal Carotid Artery

• Originates from the common carotid artery, opposite the upper border of the thyroid cartilage.
• Course: Divided into four parts (cervical, petrous, cavernous, and supracavernous).
• Termination: Enters the brain by terminating on the lateral side of the optic chiasma below the anterior perforated substance.
  • Divides into the anterior cerebral artery and middle cerebral artery.

Basilar Artery

• Origin: Formed by the union of two vertebral arteries at the lower border of the pons.
• Course: Ascends in the basilar groove of the pons.
• Termination: Divides into two posterior cerebral arteries at the upper border of the pons.

Circle of Willis

• An anastomosis (network of interconnected vessels) between the branches of the internal carotid arteries and the basilar artery.
• Located at the base of the brain in the interpeduncular fossa.
• Composed of six large arteries and three communicating arteries. This structure helps maintain blood flow to the brain even with partial blockage.

Branches of Cranial Part of Vertebral Artery

• Anterior spinal artery
• Posterior spinal artery
• Posterior inferior cerebellar artery
  • Meningeal arteries: Supplies the dura matter of posterior cranial fossa
  • Medullary arteries: Supplies the medulla oblongata

Branches of Middle Cerebral Artery

• The different parts of the brain are supplied by different branches of the middle cerebral artery. The middle cerebral artery is the largest, and supplies many areas of the brain, including the motor and sensory areas, the auditory area, Broca's area, and the sensory area of speech, and the insulae. The subdivisions are divided into Anterior temporal branch, Middle temporal branch and Posterior Temporal branch, and several gyral branches (including Parieto-occipital, Angular gyral branch) connecting the various parts of the brain.

Anterior and Posterior Cerebral Arteries

• Anterior cerebral artery: Supplies frontal lobe, medial aspects of parietal lobes, anterior corpus callosum.
• Posterior cerebral artery: Supplies occipital lobe, part of temporal lobe, inferior surface of temporal and parietal lobes.

Clinical Importance of Arteries in the Brain

• Anterior cerebral artery: Supplies motor and sensory areas of lower limbs and perineum, septal region, and the corpus callosum. Lesions in this area can result in prolonged unconsciousness and apraxia (inability to perform purposeful movements).
• Middle cerebral artery: Supplies motor and sensory areas of the body (except lower limbs), auditory area, Broca's area, and insula. Blockages can lead to significant neurological deficits.
• Posterior cerebral artery: Supplies visual cortex, center of smell, most of the thalamus and midbrain, and choroid plexuses of the ventricles.

Other Important Regions

• Corpus callosum: Supplied by the anterior cerebral artery (rostrum, genu, and body) and posterior cerebral artery (splenium).
• Choroid plexuses: Supplied by the posterior choroidal artery for the body of the lateral and inferior horn and the internal carotid for the third ventricle and posterior inferior cerebellar artery for the fourth ventricle.
• Internal capsule: Anterior part is supplied by central branches from the anterior cerebral artery; the rest is supplied by the middle cerebral artery branches, and the sublentiform part/retrolentiform of the internal capsule (including posterior part of the anterior limb and the genu) is supplied by the anterior choroidal branch of the internal carotid artery.
• Thalamus: Supplied mainly by the Posterior cerebral artery (terminal branch and posterior choroidal artery), and Posterior communicating artery coming from the internal carotid artery.
• Hypothalamus: Supplied by all arteries forming the circle of Willis.
• Cerebellum: Superior surface is supplied by superior cerebellar branches of basilar artery, inferior surface is supplied by posterior inferior cerebellar branch of vertebral artery; and anterior inferior cerebellar branch of basilar artery.
• Midbrain: Central branches of posterior cerebral artery, helped by superior cerebellar artery and posterior communicating artery.
• Pons: Anterior part (basis pontis) is supplied by pontine branches of basilar artery. Posterior part (tegmentum) is supplied by Posterior inferior cerebellar artery (lower pons); and superior cerebellar artery (upper pons).
• Medulla oblongata: Supplied by branches of vertebral artery . Anterolateral surface is supplied by medullary branches of anterior spinal artery (medially) and the 4th part of the vertebral artery (lately). Posterolateral surface is supplied by posterior inferior cerebellar artery. Gracile and cuneate tracts and nuclei is supplied by posterior spinal artery.

Test your knowledge on the arterial supply of the brain, including the vertebral and internal carotid arteries. This quiz covers their origins, paths, and terminations. Perfect for students of anatomy and physiology.