The diencephalon is a part of brain situated cranial to the midbrain and is more or less totally encompassed by the cerebrum. At the base of the brain in the region of interpeduncular fossa, is the only part of diencephalon that is exposed to the surface. 3rd ventricle is the cavity inside the diencephalon. It conveys on either side together with the lateral ventricle of the cerebral hemisphere.

The cavity of the 3rd ventricle breaks up the diencephalon into 2 (left and right) symmetrical halves.

Divisions and Subdivisions

Pars dorsalis and pars ventralis are the 2 major parts diencephalon is splitted into. These subdivisions are divided from every other by a shallow groove, the hypothalamic sulcus, which goes from interventricular foramen to the rostral end of the cerebral aqueduct of the midbrain and are viewed in midsagittal view of the brain.

Pars dorsalis is located above (dorsal) the hypothalamic sulcus and is composed of: thalamus, metathalamus and Cepithalamus.

Pars ventralis is located below (ventral) the hypothalamic sulcus and is composed of: subthalamus and hypothalamus.

Hence the diencephalon is splitted into 5 parts:

  • thalamus
  • metathalamus
  • epithalamus
  • subthalamus
  • hypothalamus

Every of these parts have additional subsections.

Divisions and subsections of the diencephalon