The tuber cinereum is a hollow eminence of gray matter located between the optic chiasma in front and the mammilary bodies. It forms part of the floor of the third ventricle. Laterally the tuber cinereum is continuous with the anterior perforated substances and anteriorly with a thin lamina, the lamina terminalis. From the under surface of the tuber cinereum a hollow conical process, the infundibulum, projects downward and forward and is attached to the posterior lobe of the hypophysis. The infundibulum, which is a hollow conical process, projects from the tuber cinereum. The infundibulum extends forward and down where it is attached to the posterior lobe of the pituitary gland.