This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
Pineal gland forms ? 
Select and explain. 
A. Floor of third ventricle, B. Anterior wall of third ventricle, C. Posterior wall of thrid ventricle, D. Roof of third ventricle
C: Posterior wall of thrid ventricle
Answer: C: Posterior wall of thrid ventricle 
Explanation: Ans. is 'c' i.e., Posterior wall of thrid ventricleBoundries of third ventricle are :-Anterior wall : Lamina terminal, anterior commissure, anterior columns of fornix.Posterior wall : Pineal body, posterior commissure, cerebral aqueduct.Roof : Ependyma lining of under surface of tela choroidea of r ventricle. The choroid plexus of third ventricle projects downwards from roof.Floor : Optic chiasma, tuber cinereum, infundibulum (pituitary stalk), mammillary body, posterior perforated substance and tegmentum of midbrain.Optic recess is seen at the junction of floor with anterior wall.Lateral wall : Medial surface of thalamus, hypothalamus and hypothalamic nuclei. Interventricular foramen (of Monro) is seen at the junction of roof with anterior and lateral wall.