WordNet
n. a narrow ventricle in the midplane below the corpus callosum; communicates with the fourth ventricle via the Sylvian aqueduct
Wikipedia
The third ventricle (ventriculus tertius) is one of four connected fluid-filled cavities comprising the ventricular system within the mammalian brain. It is a median cleft in the diencephalon between the two thalami, and is filled with cerebrospinal fluid (CSF).
It is in the midline, between the left and right lateral ventricles. Running through the third ventricle is the interthalamic adhesion, which contains thalamic neurons and fibers that may connect the two thalami.
Usage examples of "third ventricle".
Some small hypothalamic proteins have been identified tentatively in the third ventricle of the brain, which connects the hypothalamus with the thalamus, a region also within the limbic system.
This connects through a narrow aperture with the third ventricle, which is rather long and thin.
Above the third ventricle there is a connection, through another narrow aperture, with the two foremost ventricles, which lie within the cerebrum, one on either side of the fissure that divides the cerebrum into a right and left portion.
The stunning pictures on page 65, taken with an electron microscope, show two close-ups of action in the third ventricle.
To be perfectly precise, it's between our cerebral hemispheres, and right above the third ventricle of our spinal column.