Third ventricle

The third ventricle is one of the four CSF-filled cavities that together comprise the ventricular system.

Gross anatomy

The third ventricle is a median cleft between the two thalami and is bounded laterally by them and the hypothalamus. Its anterior wall is formed by the lamina terminalis, and posteriorly there is the pineal recess. There are two protrusions on the anterior surface of the third ventricle:

The third ventricle communicates with the lateral ventricles via the foramina of Monro (interventricular foramina) and with the fourth ventricle via the aqueduct of Sylvius (cerebral aqueduct).

Variant anatomy

In some patients, the two thalami meet forming the interthalamic adhesion (or massa intermedia) and when casts are made of the ventricular system, a hole is seen through the third ventricle.

Anatomy: Brain
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Article information

rID: 5780
Section: Anatomy
Tag: refs
Synonyms or Alternate Spellings:
  • 3rd ventricle

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Cases and figures

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    Figure 1: ventricular system
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    Figure 2: IVH outlining the recesses of the third ventricle
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    Figure 4: coronal brain through 3rd ventricle
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    Figure 3: ventricles superimposed on lateral brain
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