4.1 blood supply

Major Blood Vessels of the Posterior Arterial Circulation

  • Vertebral Arteries: Branch off the subclavian arteries; supply posterior circulation.

  • Basilar Artery: Formed by the convergence of vertebral arteries; supplies brainstem and cerebellum.

  • Posterior Cerebral Arteries (PCA): Terminal bifurcation of the basilar artery; supplies posterior regions of the cerebrum.

Major Blood Vessels of the Anterior Arterial Circulation

  • Common Carotid Arteries: Bifurcate into internal and external carotid arteries.

  • Internal Carotid Artery (ICA): Ascends into the skull; supplies anterior cerebral circulation.

  • Anterior Cerebral Artery (ACA): Branch of ICA; supplies medial portions of the frontal and parietal lobes.

  • Middle Cerebral Artery (MCA): Largest branch of ICA; supplies lateral surface of the cerebral hemispheres.

Broad Regions Supplied by Major Cerebral Arteries

  • Anterior Cerebral Artery (ACA): Medial aspects of frontal and parietal lobes.

  • Middle Cerebral Artery (MCA): Lateral aspects of frontal, parietal, and temporal lobes.

  • Posterior Cerebral Artery (PCA): Occipital lobe and inferior parts of the temporal lobe.

Clinical Significance of Blood Supply Impairments

  • Impairments in cerebral blood supply can lead to neurological deficits such as motor paralysis, sensory loss, aphasia, and visual disturbances. Prompt recognition and treatment are critical to minimizing neuronal loss and improving outcomes.

Major Dural Venous Sinuses of the Brain

  • Superior Sagittal Sinus: Runs along the top of the brain; drains into the internal jugular veins.

  • Transverse Sinus: Runs horizontally; drains blood from the superior sagittal sinus.

  • Sigmoid Sinus: Continuation of the transverse sinus; drains into the internal jugular vein.

  • Straight Sinus: Drains the deep cerebral veins and connects with the transverse sinus.

Flow of Venous Blood Away from the Brain

  1. Blood from brain tissue drains into cerebral veins.

  2. Cerebral veins empty into dural venous sinuses.

  3. The dural venous sinuses drain into the internal jugular veins.

  4. Internal jugular veins carry blood to the superior vena cava and then to the heart for re-oxygenation.