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thalamus

Which brain ventricle lies next to the thalamus?

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Diagram of a human brain showing a median sagittal section, highlighting the fourth ventricle and cerebellum in the hindbrain, with labeled anatomical structures including the pons, medulla oblongata, and central canal of the spinal cord. — thalamus Sagittal section of the human brain, showing structures of the cerebellum, brainstem, and cerebral ventricles.

The thalamus is located deep within the brain, where it forms the majority of the lateral walls of the third ventricle.1