Which artery supplies the thalamus, hypothalamus, and optic chiasm?

• A. Anterior Communicating Artery
• B. Posterior Communicating Artery
• C. Anterior Cerebral Artery
• D. Middle Cerebral Artery

Answer: (B)

Midline deep brain structures rely on perforating arteries from the posterior circulation. The posterior communicating artery is part of the Circle of Willis and gives off perforators that reach deep, midline regions such as the thalamus and hypothalamus, and contribute to the blood supply of the optic pathway around the chiasm. In contrast, the anterior communicating artery mainly serves as a connecting vessel between the two anterior cerebral arteries and doesn’t provide direct deep penetrating supply. The anterior cerebral and middle cerebral arteries feed mainly the medial frontal/parietal regions and the lateral cortical surface, respectively, rather than the deep midline structures in question. So, the posterior communicating artery best explains the vascular supply to the thalamus, hypothalamus, and optic chiasm.