Human brain left - midsagitttal view - closeup

1. Corpus callosum, Rostrum
2. Corpus callosum, Genu
3. Corpus callosum, Corpus
4. Corpus callosum, Splenium
5. Septum pellucidum
6. Fornix, Corpus
7. Glandula epiphysialis
8. Recessus pinealis
9. Habenula
10. Stria medullaris thalami
11. Thalamus (Pars dorsalis)
12. Adhaesio interthalamica
13. Plexus choroideus
14. Foramen interventriculare
15. Comissura anterior
16. Hypothalamus
17. Lamina terminalis
18. Recessus supraopticus
19. Recessus infundibuli
20. Infundibulum
21. Tuber cinerum
22. Corpora mamillaria
23. Sulcus hypothalamicus (blue line)
24. Mesencephalon (Crus cerebri)
25. Tegmentum mesencephali
26. Aqaeductus mesencephali
27. Tectum mesencephali, a) Colliculus superior B) C. inferior
28. Pons
29. Ventriculus quartus
30. Cerebellum
31. Comissura posterior

The Thalamus (Diencephalon) is part of the Forebrain and is divided into Dorsal Thalamus (Superior), Hypothalamus (Inferior and Medial) and Subthalamus (Lateral to Hypothalamus).

On a half brain specimen, the Thalamus can be identified. The Thalamus (anteroom) is connected caudally with the midbrain and rostrally with the cerebral hemispheres. Note that the walls of the 3rd ventricle are completely formed by the Thalamus. The Hypothalamic Sulcus separates the Dorsal Thalamus superiorly from the Hypothalamus inferiorly. The subthalamus is located lateral to the hypothalamus and is not visible here.

The anterior wall of the 3rd ventricle is a thin sheet of tissue called the Lamina Terminalis. In the Dorsal Thalamus note the Interthalamic Adhesion (Massa Intermedia), and the three parts of the Epithalamus: Stria Medullaris Thalami, Habenula, and the Pineal Gland. The floor of the Hypothalamus is made up of the Infundibulum, which connects with the pituitary gland, and posteriorly, the Tuber Cinereum and Mammillary Body.