Diencephalon
Diencephalon
Definition
The diencephalon is connected above and in front with the cerebral hemispheres; behind with the midbrain.
Its upper surface is concealed by the corpus callosum, and is covered by a fold of pia mater, named the tela chorioidea of the third ventricle; inferiorly it reaches to the base of the brain.
The diencephalon comprises:
1- the thalamencephalon
2 - the pars mamillaris hypothalami
3 - the posterior part of the third ventricle
For descriptive purposes, however, it is more convenient to consider the whole of the third ventricle and its boundaries together; this necessitates the inclusion, under this heading, of the pars optica hypothalami and the corresponding part of the third ventricle—structures which properly belong to the telencephalon.
References
This definition incorporates text from a public domain edition of Gray's Anatomy (20th U.S. edition of Gray's Anatomy of the Human Body, published in 1918 – from http://www.bartleby.com/107/).
