Third ventricle

Last edited and medically reviewed by Alaric Steinmetz on 31.12.2023

Synonyms: Third ventricle, III Ventrikel, 3. Ventrikel, Ventriculus tertius cerebri

The third ventricle (Ventriculus tertius cerebri) is part of the Ventricular system and receives cerebrospinal fluid from both Lateral ventricles via the Foramen of Monro.

Anatomy

The third ventricle is bounded by the following anatomical structures:

Lateral: Thalamus
Ventral: Hypothalamus and Optic chiasm
Dorsal: Glandula pinealis, Commissura posterior, Commissura habenularum
Rostral: Lamina terminalis and Anterior commissure
Caudal: tegmentum of the midbrain
Cranial: Fornix cerebri

Cerebrospinal fluid flow

The Cerebrospinal fluid flows from the third ventricle via the cerebral Aqueduct (aqueductus mesencephali) into the fourth ventricle.

Figure

Third ventricle — Illustration of the third ventricle (shaded red) in an anatomical illustration adapted from Gray's Anatomy, Figure 736.

Third ventricle, sagittal view — Sagittal section through the third ventricle. Figure adapted from Albert Rhoton 2002 in Neurosurgery.

Endoscopic view of the third ventricle — Endoscopic view into the third ventricle through a supracerebellar infratentorial approach, showing the interthalamic adhesion, fornix, and anterior commissure. Figure adapted from Rhomberg T and Henry WSS. Microsurgical Resection of a Pineal Cyst via a Paramedian Supracerebellar Infratentorial Approach. World Neurosurgery 185 (2024): 113. DOI 10.1016/j.wneu.2024.02.049

Imaging

Third ventricle on MRI — Third ventricle in the sagittal plane on a contrast-enhanced T1 MRI sequence.

Third ventricle on axial MRI — Third ventricle on axial MRI using a T1 contrast-enhanced sequence.

Third ventricle on MRI — Coronal T1 contrast-enhanced MRI sequence showing the third ventricle.

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