Third ventricle
Ventriculus tertius
Definition
The third ventricle is a narrow cavity located at the center of the diencephalon, separating its right and left halves.
Its walls and roof are formed by the lamina terminalis and the choroid tela, which gives rise to the choroid plexuses. It communicates with the lateral ventricles via the interventricular foramen and with the mesencephalon through the cerebral aqueduct.
Several recesses are present, including the optic recess and the neurohypophyseal (infundibular) recess. The third ventricle serves as the central cavity of the diencephalon, ensuring the circulation of cerebrospinal fluid and housing several circumventricular organs, such as the subcommissural organ and the subfornical organ, where the blood–brain barrier is reduced and which are involved in endocrine and homeostatic regulation.
References
Barone R, Bortolami R. Anatomie comparée des mammifères domestiques, Tome 6, Neurologie I, Vigot, Paris, 2004.
Evans HE, de Lahunta A. Miller’s anatomy of the dog, 4th edition, Elsevier Saunders, St Louis, 2012.
