What is the third ventricle and where is it located?

The third ventricle is the narrow midline cavity of the diencephalon. It is a vertical slit located between the two thalami and parts of the hypothalamus.

How does the third ventricle communicate with other brain ventricles?

It communicates anteriorly with each lateral ventricle via the interventricular foramen (of Monro) and posteriorly with the fourth ventricle via the cerebral aqueduct (of Sylvius).

What are the key boundaries of the third ventricle?

Key boundaries include the anterior wall (column of fornix, anterior commissure, lamina terminalis), posterior wall (pineal gland, posterior commissure, start of cerebral aqueduct), and floor (optic chiasma, tuber cinereum, mammillary bodies, tegmentum of the midbrain).

What are the recesses of the third ventricle and their functions?

Recesses are extensions into neighboring areas, including the infundibular recess (into the pituitary stalk), optic recess (above the optic chiasma), and pineal recess (between laminae of the pineal stalk).

What role does the choroid plexus play in the third ventricle?

The choroid plexus, hanging from the tela choroidea in the roof, produces cerebrospinal fluid (CSF).

Why is the third ventricle clinically significant for CSF flow?

Its narrow shape makes it vulnerable to obstruction by tumors or malformations, leading to increased intracranial pressure in adults or hydrocephalus in children due to CSF accumulation.

How is obstruction of the third ventricle diagnosed?

Diagnosis can involve ventriculography to identify the site of obstruction.

Third Ventricle – Boundaries & Recesses

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