Interventricular foramina (neuroanatomy)

Interventricular foramina
The lateral ventricles connected to the third ventricle by the interventricular foramina.
Cerebrospinal fluid is present in spaces in and around the brain.
Details
Part of	Ventricular system
Identifiers
Latin	foramen interventriculare, foramen Monroi
MeSH	A08.186.211.276
NeuroNames	hier-430
TA	A14.1.08.411
FMA	75351
Anatomical terms of neuroanatomy []

In the brain, the interventricular foramina (or foramina of Monro) are channels that connect the paired lateral ventricles with the third ventricle at the midline of the brain. As channels, they allow cerebrospinal fluid (CSF) produced in the lateral ventricles to reach the third ventricle and then the rest of the brain's ventricular system. They also contain choroid plexus, a specialized CSF-producing structure, that is continuous with that of the lateral and third ventricles, and which is also present in the fourth ventricle.

The interventricular foramina are two holes (Latin: foramen, pl. foramina) that connect the lateral ventricles on the left and the right to the third ventricle. They are located on the underside near the midline of the lateral ventricles, and join the third ventricle where its roof meets its anterior surface. In front of the foramen is the fornix and behind is the thalamus. The foramen is normally crescent-shaped, but rounds and increases in size depending on the size of the lateral ventricles.

The development and shape of the ventricular system relates to the differential development of different parts of the brain, with the ventricular system ultimately arising from the neural tube. The lateral ventricles remain connected to the third ventricle throughout development, themselves developing as outpouchings from the third ventricle. The foramina develop slowly in a forward and outward direction as the fornix grows in size.

The interventricular foramina connect the lateral ventricles to the third ventricle. This allows cerebrospinal fluid produced in the lateral ventricles to reach the third ventricle and then the rest of the brain's ventricular system.

The walls of the interventricular foramina contain choroid plexus, a specialized structure that produces cerebrospinal fluid. The choroid plexus of the third ventricles continues through the foramina into the lateral ventricles.