The tuber cinereum is a hollow eminence of gray substance situated between the corpora mammillaria behind, and the optic chiasma in front.    From Wordnik.com.  [IX. Neurology. 4c. The Fore-brain or Prosencephalon] Reference

Between the tuber cinereum and the corpora mammillaria a small elevation, with a corresponding depression in the third ventricle, is sometimes seen.    From Wordnik.com.  [IX. Neurology. 4c. The Fore-brain or Prosencephalon] Reference

The floor slopes downward and forward and is formed mainly by the structures which constitute the hypothalamus: from before backward these are: the optic chiasma, the tuber cinereum and infundibulum, and the corpora mammillaria.    From Wordnik.com.  [IX. Neurology. 4c. The Fore-brain or Prosencephalon] Reference

The Hypothalamus (Fig. 720) includes the subthalamic tegmental region and the structures forming the greater part of the floor of the third ventricle, viz., the corpora mammillaria, tuber cinereum, infundibulum, hypophysis, and optic chiasma.    From Wordnik.com.  [IX. Neurology. 4c. The Fore-brain or Prosencephalon] Reference