The third ventricle is a narrow funnel-shaped cavity of the brain that is located in the midline between the two hemispheres of the diencephalon of the forebrain. The third ventricle makes up the central part of the brain and facilitates communication between other ventricles.
An Overview of Brain Anatomy
Similar to the other brain ventricles, the main function of the third ventricle is to produce, secrete, and convey CSF. It also has several very important secondary roles, such as protection of the brain from trauma and injury and transport of nutrients and waste from the body’s central nervous system.
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Anatomy
Structure
The third ventricle is a cuboid-shaped structure that has a roof, floor, and four walls—the anterior, posterior, and two lateral walls, respectively.
Location
The third ventricle is a midline structure. It is found between the cerebral hemispheres.
It communicates directly with each lateral ventricle via the foramen of Monro and with the fourth ventricle via the aqueduct of Sylvius.
The third ventricle is situated between the right and the left thalamus. It has two protrusions on its top surface—the supra-optic recess (located above the optic chiasm) and the infundibular recess (located above the optic stalk).
Anatomical Variations
There are several variations of the third ventricle.The most common variations are:
Enlarged Ventricles in Infants
It is also common for infants to have mildly enlarged ventricles. Ventriculomegaly can be a benign finding, particularly in isolated cases. However, it can also be indicative of a more severe condition such as chromosomal abnormalities, congenital infection, cerebral vascular accident, or another fetal abnormality associated with developmental delay.
Colloid Cysts
Colloid cysts are benign, slow-growing lesions of the third ventricle. They can present as incidental findings on imaging or with symptoms of obstructive hydrocephalus.
The causes of colloid cysts are unknown, but they seem to run in families. Researchers have pointed to a potential association between familial colloid cysts and congenital inguinal hernia.
Schizophrenia
One study found that people withschizophreniaand their healthy siblings have larger third ventricles. The findings suggest that there could be related genetic defects that produce a susceptibility to the mental health condition.
Function
The third ventricle is the main site for CSF production. CSF has three main roles in the brain:
Associated Conditions
Abnormalities of the third ventricle are associated with other medical conditions. Some of the most common conditions associated with the third ventricle are:
Trauma during brain surgery or an accident can also cause meningitis or ventriculitis, but it is exceedingly rare.
Infections of the Brain
Tests
In adults, if there is suspicion of a tumor, hydrocephalus, or congenital malformation, a doctor may use the following to help diagnose the condition:
An Overview of Diagnostic Brain Tests
Mild hydrocephalus can be treated with a wait-and-see approach, but more severe cases may need treatment with medication or surgery, such as a ventriculoperitoneal shunt or an endoscopic third ventriculostomy.
9 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Eichele G, Bodenschatz E, Ditte Z, et al.Cilia-driven flows in the brain third ventricle.Philos Trans R Soc Lond B Biol Sci. 2020;375(1792):20190154. doi:10.1098/rstb.2019.0154Glastonbury CM, Osborn AG, Salzman KL.Masses and malformations of the third ventricle: normal anatomic relationships and differential diagnoses.RadioGraphics. 2011;31(7):1889-1905. doi:10.1148/rg.317115083Sughrue ME, Chiou J, Burks JD, et al.Anatomic variations of the floor of the third ventricle: an endoscopic study.World Neurosurg. 2016;90:211-227. doi:10.1016/j.wneu.2016.02.037Rapoport BI, Baird LC, Cohen AR.Third-ventricular neurocysticercosis: hydraulic maneuvers facilitating endoscopic resection.Childs Nerv Syst. 2014;30(3):541-546. doi:10.1007/s00381-013-2273-7Heaphy-Henault KJ, Guimaraes CV, Mehollin-Ray AR, et al.Congenital aqueductal stenosis: findings at fetal MRI that accurately predict a postnatal diagnosis.Am J Neuroradiol. 2018;39(5):942-948. doi:10.3174/ajnr.A5590Schimmel MS, Hammerman C, Bromiker R, et al.Third ventricle enlargement among newborn infants with trisomy 21.Pediatrics. 2006;117(5):e928-e931.Calderón C, Fernandez-de Thomas RJ, De Jesus O.Familial colloid cysts of the third ventricle: case report and literature review.Asian J Neurosurg. 2020;15(2):414-417. doi:10.4103/ajns.AJNS_332_19Staal WG, Hulshoff Pol HE, Schnack HG, et al.Structural brain abnormalities in patients with schizophrenia and their healthy siblings.Am J Psychiatry. 2000;157(3):416-421. doi:10.1176/appi.ajp.157.3.416American Association of Neurological Surgeons.Adult-onset hydrocephalus.
9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Eichele G, Bodenschatz E, Ditte Z, et al.Cilia-driven flows in the brain third ventricle.Philos Trans R Soc Lond B Biol Sci. 2020;375(1792):20190154. doi:10.1098/rstb.2019.0154Glastonbury CM, Osborn AG, Salzman KL.Masses and malformations of the third ventricle: normal anatomic relationships and differential diagnoses.RadioGraphics. 2011;31(7):1889-1905. doi:10.1148/rg.317115083Sughrue ME, Chiou J, Burks JD, et al.Anatomic variations of the floor of the third ventricle: an endoscopic study.World Neurosurg. 2016;90:211-227. doi:10.1016/j.wneu.2016.02.037Rapoport BI, Baird LC, Cohen AR.Third-ventricular neurocysticercosis: hydraulic maneuvers facilitating endoscopic resection.Childs Nerv Syst. 2014;30(3):541-546. doi:10.1007/s00381-013-2273-7Heaphy-Henault KJ, Guimaraes CV, Mehollin-Ray AR, et al.Congenital aqueductal stenosis: findings at fetal MRI that accurately predict a postnatal diagnosis.Am J Neuroradiol. 2018;39(5):942-948. doi:10.3174/ajnr.A5590Schimmel MS, Hammerman C, Bromiker R, et al.Third ventricle enlargement among newborn infants with trisomy 21.Pediatrics. 2006;117(5):e928-e931.Calderón C, Fernandez-de Thomas RJ, De Jesus O.Familial colloid cysts of the third ventricle: case report and literature review.Asian J Neurosurg. 2020;15(2):414-417. doi:10.4103/ajns.AJNS_332_19Staal WG, Hulshoff Pol HE, Schnack HG, et al.Structural brain abnormalities in patients with schizophrenia and their healthy siblings.Am J Psychiatry. 2000;157(3):416-421. doi:10.1176/appi.ajp.157.3.416American Association of Neurological Surgeons.Adult-onset hydrocephalus.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Eichele G, Bodenschatz E, Ditte Z, et al.Cilia-driven flows in the brain third ventricle.Philos Trans R Soc Lond B Biol Sci. 2020;375(1792):20190154. doi:10.1098/rstb.2019.0154Glastonbury CM, Osborn AG, Salzman KL.Masses and malformations of the third ventricle: normal anatomic relationships and differential diagnoses.RadioGraphics. 2011;31(7):1889-1905. doi:10.1148/rg.317115083Sughrue ME, Chiou J, Burks JD, et al.Anatomic variations of the floor of the third ventricle: an endoscopic study.World Neurosurg. 2016;90:211-227. doi:10.1016/j.wneu.2016.02.037Rapoport BI, Baird LC, Cohen AR.Third-ventricular neurocysticercosis: hydraulic maneuvers facilitating endoscopic resection.Childs Nerv Syst. 2014;30(3):541-546. doi:10.1007/s00381-013-2273-7Heaphy-Henault KJ, Guimaraes CV, Mehollin-Ray AR, et al.Congenital aqueductal stenosis: findings at fetal MRI that accurately predict a postnatal diagnosis.Am J Neuroradiol. 2018;39(5):942-948. doi:10.3174/ajnr.A5590Schimmel MS, Hammerman C, Bromiker R, et al.Third ventricle enlargement among newborn infants with trisomy 21.Pediatrics. 2006;117(5):e928-e931.Calderón C, Fernandez-de Thomas RJ, De Jesus O.Familial colloid cysts of the third ventricle: case report and literature review.Asian J Neurosurg. 2020;15(2):414-417. doi:10.4103/ajns.AJNS_332_19Staal WG, Hulshoff Pol HE, Schnack HG, et al.Structural brain abnormalities in patients with schizophrenia and their healthy siblings.Am J Psychiatry. 2000;157(3):416-421. doi:10.1176/appi.ajp.157.3.416American Association of Neurological Surgeons.Adult-onset hydrocephalus.
Eichele G, Bodenschatz E, Ditte Z, et al.Cilia-driven flows in the brain third ventricle.Philos Trans R Soc Lond B Biol Sci. 2020;375(1792):20190154. doi:10.1098/rstb.2019.0154
Glastonbury CM, Osborn AG, Salzman KL.Masses and malformations of the third ventricle: normal anatomic relationships and differential diagnoses.RadioGraphics. 2011;31(7):1889-1905. doi:10.1148/rg.317115083
Sughrue ME, Chiou J, Burks JD, et al.Anatomic variations of the floor of the third ventricle: an endoscopic study.World Neurosurg. 2016;90:211-227. doi:10.1016/j.wneu.2016.02.037
Rapoport BI, Baird LC, Cohen AR.Third-ventricular neurocysticercosis: hydraulic maneuvers facilitating endoscopic resection.Childs Nerv Syst. 2014;30(3):541-546. doi:10.1007/s00381-013-2273-7
Heaphy-Henault KJ, Guimaraes CV, Mehollin-Ray AR, et al.Congenital aqueductal stenosis: findings at fetal MRI that accurately predict a postnatal diagnosis.Am J Neuroradiol. 2018;39(5):942-948. doi:10.3174/ajnr.A5590
Schimmel MS, Hammerman C, Bromiker R, et al.Third ventricle enlargement among newborn infants with trisomy 21.Pediatrics. 2006;117(5):e928-e931.
Calderón C, Fernandez-de Thomas RJ, De Jesus O.Familial colloid cysts of the third ventricle: case report and literature review.Asian J Neurosurg. 2020;15(2):414-417. doi:10.4103/ajns.AJNS_332_19
Staal WG, Hulshoff Pol HE, Schnack HG, et al.Structural brain abnormalities in patients with schizophrenia and their healthy siblings.Am J Psychiatry. 2000;157(3):416-421. doi:10.1176/appi.ajp.157.3.416
American Association of Neurological Surgeons.Adult-onset hydrocephalus.
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