Makindo Medical Notes

Related Subjects: |Cerebral Arterial Perfusion and Clinical Correlates |Anterior circulation Brain |Posterior circulation Brain |Acute Stroke Assessment (ROSIER&NIHSS)

🩸 The vertebral arteries provide about one-third of the cerebral blood supply, forming the vital posterior circulation. Their branches supply the medulla, pons, cerebellum, and occipital lobes — regions critical for life-sustaining functions.

🧭 Vertebral Artery Course

• Arises as the first branch of the subclavian artery on each side.
• Enters the transverse foramen at C6, ascends through the foramina up to C1.
• Curves posteriorly around the atlas and enters the skull via the foramen magnum.
• At the lower border of the pons, the two vertebral arteries unite to form the basilar artery.

🌿 Major Branches

• Posterior Inferior Cerebellar Artery (PICA) 🧠
  • Largest branch of the vertebral artery.
  • Supplies the lateral medulla and inferior cerebellum.
  • Occlusion → Wallenberg’s syndrome (lateral medullary syndrome).
• Anterior Spinal Artery 🟠
  • Formed by contributions from both vertebral arteries; supplies ventral medulla and anterior spinal cord.
• Posterior Spinal Artery 🔵
  • Supplies dorsal medulla and dorsal columns of spinal cord.
• Basilar Artery 🏗️
  • Formed by vertebral fusion; supplies pons, cerebellum, and inner ear.
• Anterior Inferior Cerebellar Artery (AICA) ⚖️
  • Supplies lateral pons and anterior inferior cerebellum.
• Superior Cerebellar Artery ⛰️
  • Supplies superior cerebellum and lateral pons.
• Pontine Arteries ➕
  • About 12 small perforators branching at right angles from the basilar artery to supply the medial pons.
• Internal Auditory (Labyrinthine) Artery 🎧
  • Travels with CN VIII to supply the inner ear; infarction can cause sudden hearing loss and vertigo.
• Posterior Cerebral Artery (PCA) 👁️
  • Embryologically linked to the internal carotid; later supplied by the basilar.
  • Wraps around the cerebral peduncle to supply the occipital lobe and inferior temporal cortex.

🌐 Posterior Cerebral Artery (PCA) Branches

• Postero-medial Ganglionic Branches → thalami + walls of 3rd ventricle.
• Posterior Choroidal Branches → choroid plexus of 3rd ventricle.
• Postero-lateral Ganglionic Branches → lateral thalamus.
• Anterior Temporal Branch → uncus + anterior fusiform gyrus.
• Posterior Temporal Branch → inferior temporal gyri, lingual gyrus, cuneus, occipital cortex.
• Parieto-occipital Branch → parieto-occipital region, calcarine cortex.

🧑‍⚕️ Clinical Relevance

• 🔸 PICA stroke → Wallenberg’s syndrome (vertigo, ataxia, ipsilateral facial sensory loss, contralateral body sensory loss).
• 🔸 AICA stroke → lateral pontine syndrome (facial weakness, vertigo, hearing loss).
• 🔸 Basilar occlusion → catastrophic brainstem infarction, “locked-in syndrome.”
• 🔸 PCA stroke → contralateral homonymous hemianopia ± alexia without agraphia (if dominant hemisphere, splenium involvement).