Third ventricle
Ventriculus tertius
Definition
Third ventricle is a slit-like space situated within the diencephalon. It is part of a widespread network of cerebrospinal fluid containing spaces or ventricles present within the central nervous system. Rostrally, the third ventricle communicates with the lateral ventricle on each side through interventricular foramen (a.k.a. foramen of Monroe), while caudally it connects with the fourth ventricle via the cerebral aqueduct.
The third ventricle is bounded by several important structures. For instance, its lateral wall is formed by thalamus and hypothalamus. Anterior wall comprises of pre-optic area (including lamina terminalis and anterior commissure). Posterior wall is formed by a series of structure. From top to bottom, these include the habenular commissure, pineal recess, posterior commissure and the opening for the cerebral aqueduct. Inferior wall or floor is formed by the optic chiasma, tuber cinereum, infundibulum, and mamillary bodies, posterior to which lies the tegmentum of the midbrain. Superior wall or roof is related to fornix and corpus callosum. A tuft of vascular pia mater (tela choroidea) invaginates from the roof to form choroid plexus, which hangs within the cavity of the third ventricle and is responsible for production of cerebrospinal fluid.
Text written by Muhammad A. Javaid, MD, PhD © 2022 IMAIOS.
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