Lateral ventricle

At a glance

English

Lateral ventricle

Latin (TA2)

Ventriculus lateralis

System

Brain and spinal cord

Region

Head

Side

Paired, left and right

About the lateral ventricle

Each cerebral hemisphere contains one lateral ventricle, the largest cavity of the ventricular system. It is lined by ependyma, holds cerebrospinal fluid (CSF) and in cross-section is roughly triangular and flattened. In shape it follows the curve of the growing hemisphere: from the frontal lobe it arches back over the thalamus, then turns down and forward into the temporal lobe, so that it forms a C open to the front. A side branch runs back into the occipital lobe. It is described as a body with three horns, joined by a wider area called the atrium (trigone).

The anterior (frontal) horn lies in front of the interventricular foramen, through which the ventricle drains into the third ventricle. Its roof and front are made by the corpus callosum (the genu and, below, the rostrum), its medial wall by the septum pellucidum, which separates the two anterior horns, and its lateral wall and floor by the bulging head of the caudate nucleus. The body runs back under the corpus callosum to the splenium. Its floor carries, from lateral to medial, the body of the caudate nucleus, the stria terminalis with the thalamostriate vein, the upper surface of the thalamus, the choroid plexus and the edge of the fornix.

At the atrium, behind the thalamus, the body meets two horns. The posterior (occipital) horn extends back into the occipital lobe; on its medial wall the forceps major of the corpus callosum raises a bulb above, and the calcarine sulcus raises the calcar avis below, while the tapetum forms the roof and lateral wall. The inferior (temporal) horn curves down and forward to within a few centimetres of the temporal pole. The caudate tail runs along its roof towards the amygdala at its tip. Its floor is raised by the hippocampus and fimbria medially and by the collateral eminence laterally. The choroid plexus enters through the choroid fissure along the medial side of the body and inferior horn and is largest at the atrium, where it forms the glomus.

The choroid plexus here makes most of the brain's CSF. If outflow is blocked or absorption fails, the ventricles enlarge in hydrocephalus; they also widen slowly with age and in conditions where brain tissue shrinks, such as Alzheimer disease.

Function and supply

Function

Holds and produces CSF through its choroid plexus and passes it through the interventricular foramen to the third ventricle; the fluid cushions and supports the brain.

Blood supply

Its choroid plexus is supplied by the anterior choroidal artery (from the internal carotid) and the lateral posterior choroidal arteries (from the posterior cerebral), and drained by the choroidal and thalamostriate veins into the internal cerebral vein.