The lateral ventricles are the two largest ventricles of the

brain A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a ve ...

and contain

cerebrospinal fluid Cerebrospinal fluid (CSF) is a clear, colorless body fluid found within the tissue that surrounds the brain and spinal cord of all vertebrates. CSF is produced by specialised ependymal cells in the choroid plexus of the ventricles of the ...

(CSF). Each

cerebral hemisphere The vertebrate cerebrum (brain) is formed by two cerebral hemispheres that are separated by a groove, the longitudinal fissure. The brain can thus be described as being divided into left and right cerebral hemispheres. Each of these hemispheres ...

contains a lateral ventricle, known as the left or right ventricle, respectively. Each lateral ventricle resembles a C-shaped cavity that begins at an inferior horn in the

temporal lobe The temporal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain. The temporal lobe is involved in pro ...

, travels through a body in the

parietal lobe The parietal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The parietal lobe is positioned above the temporal lobe and behind the frontal lobe and central sulcus. The parietal lobe integrates sensory informa ...

and

frontal lobe The frontal lobe is the largest of the four major lobes of the brain in mammals, and is located at the front of each cerebral hemisphere (in front of the parietal lobe and the temporal lobe). It is parted from the parietal lobe by a groove be ...

, and ultimately terminates at the interventricular foramina where each lateral ventricle connects to the single, central

third ventricle The third ventricle is one of the four connected ventricles of the ventricular system within the mammalian brain. It is a slit-like cavity formed in the diencephalon between the two thalami, in the midline between the right and left lateral ...

. Along the path, a posterior horn extends backward into the

occipital lobe The occipital lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The name derives from its position at the back of the head, from the Latin ''ob'', "behind", and ''caput'', "head". The occipital lobe is the vi ...

, and an anterior horn extends farther into the frontal lobe.

Structure

Each lateral ventricle takes the form of an elongated curve, with an additional anterior-facing continuation emerging inferiorly from a point near the posterior end of the curve; the junction is known as the ''trigone of the lateral ventricle''. The centre of the superior curve is referred to as the ''body'', while the three remaining portions are known as ''horns'' (''cornua'' in Latin); they are usually referred to by their position relative to the ''body'' (anterior, posterior, or inferior), or sometimes by the lobe of the cerebral cortex into which they extend. Though somewhat flat, the lateral ventricles have a vaguely triangular cross-section.

Ependyma The ependyma is the thin neuroepithelial ( simple columnar ciliated epithelium) lining of the ventricular system of the brain and the central canal of the spinal cord. The ependyma is one of the four types of neuroglia in the central nervous syst ...

, which are

neuroepithelial cells Neuroepithelial cells, or neuroectodermal cells, form the wall of the closed neural tube in early embryonic development. The neuroepithelial cells span the thickness of the tube's wall, connecting with the pial surface and with the ventricular or ...

, line the ventricular system including the lateral ventricles. Between the inferior horn and the main body of the ventricle is the

putamen The putamen (; from Latin, meaning "nutshell") is a round structure located at the base of the forebrain (telencephalon). The putamen and caudate nucleus together form the dorsal striatum. It is also one of the structures that compose the basal ...

, which emerges from the head of the

caudate nucleus The caudate nucleus is one of the structures that make up the corpus striatum, which is a component of the basal ganglia in the human brain. While the caudate nucleus has long been associated with motor processes due to its role in Parkinson's d ...

, and sits above the tapetum; a small number of further connections passing through the occipital tapetum to join the putamen to portions of the caudate nucleus tail adjoining the anterior horn. Below the putamen sits the globus pallidus, with which it connects. These structures bounding the lateral ventricles form a frame curving around the

thalamus The thalamus (from Greek θάλαμος, "chamber") is a large mass of gray matter located in the dorsal part of the diencephalon (a division of the forebrain). Nerve fibers project out of the thalamus to the cerebral cortex in all directions, ...

, which itself constitutes the main structure bounding the third ventricle. Were it not for the

choroid plexus The choroid plexus, or plica choroidea, is a plexus of cells that arises from the tela choroidea in each of the ventricles of the brain. Regions of the choroid plexus produce and secrete most of the cerebrospinal fluid (CSF) of the central nerv ...

, a cleft-like opening would be all that lay between the lateral ventricle and the thalamus; this cleft constitutes the lower part of the choroid fissure. The thalamus primarily communicates with the structures bounding the lateral ventricles via the globus pallidus, and the anterior extremities of the fornix (the

mamillary bodies The mammillary bodies are a pair of small round bodies, located on the undersurface of the brain that, as part of the diencephalon, form part of the limbic system. They are located at the ends of the anterior arches of the fornix. They consis ...

Anterior horns of lateral ventricle

The anterior horn of the lateral ventricle is also known as the ''frontal horn'' as it extends into the

. The anterior horn connects to the

, via the interventricular foramen. This portion of the lateral ventricle impinges on the frontal lobe, passing anteriorly and laterally, with slight inclination inferiorly. It is separated from the anterior horn of the other lateral ventricle by a thin neural sheet -

septum pellucidum The septum pellucidum (Latin for "translucent wall") is a thin, triangular, vertical double membrane separating the anterior horns of the left and right lateral ventricles of the brain. It runs as a sheet from the corpus callosum down to the f ...

, which thus forms its medial boundary. The boundary facing exterior to the ventricle curvature is formed by the

corpus callosum The corpus callosum (Latin for "tough body"), also callosal commissure, is a wide, thick nerve tract, consisting of a flat bundle of commissural fibers, beneath the cerebral cortex in the brain. The corpus callosum is only found in placental m ...

- the ''floor'' at the limit of the ventricle is the upper surface of the

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ships * Ros ...

(the reflected portion of the corpus callosum), while nearer the ''body'' of the ventricle, the ''roof'' consists of the posterior surface of the '' genu''. The remaining boundary - that facing interior to the ventricle curvature - comprises the posterior edge of the

Frontal horn cyst A frontal horn cyst or connatal cyst is a cystic area in the brain. They are sometimes found in newborn babies and do not appear to cause any developmental problems. It is adjacent to the superolateral margin of the body and frontal horn of the ...

s are sometimes found on the frontal horn as a normal variant.

Body of the lateral ventricle

The body of the lateral ventricle, or central part is the part of the ventricle between the anterior horn and the trigone. Its roof is bound by the

tapetum of the corpus callosum The corpus callosum (Latin for "tough body"), also callosal commissure, is a wide, thick nerve tract, consisting of a flat bundle of commissural fibers, beneath the cerebral cortex in the brain. The corpus callosum is only found in placental ma ...

- and is separated medially from the other lateral ventricle by the

. The tail of the caudate nucleus forms the upper portion of the lateral edge, but it is not large enough to cover the whole boundary. Immediately below the tail of the caudate nucleus, the next portion of the lateral edge is formed by the comparatively narrow stria terminalis, which sits upon the superior thalamostriate vein. The main part of the

fornix of the brain The fornix (from lat, fornix, lit=arch) is a C-shaped bundle of nerve fibers in the brain that acts as the major output tract of the hippocampus. The fornix also carries some afferent fibers to the hippocampus from structures in the diencephalon ...

forms the next narrow portion of the lateral boundary, which is completed medially by a

, which serves both ventricles.

Trigone of lateral ventricle

The trigone of the lateral ventricle is the area where the part of the body forms a junction with the inferior horn and the posterior horn. This area is referred to as the atrium of the lateral ventricle, and is where the choroid plexus is enlarged as the choroid glomus. As a triangular surface feature of the floor of this part of the lateral ventricle it is known as the collateral trigone.

Posterior horn of lateral ventricle

The posterior horn of lateral ventricle, or ''occipital horn'', impinges into the

in a posterior direction, initially laterally but subsequently curving medially and lilting inferiorly on the lateral side. The tapetum of the Corpus Callosum continues to form the roof, which due to the lilt is also the lateral edge. However, the posterior and anterior ends of the Corpus Callosum are characterised by tighter bundling, known as ''forceps'' (due to the resulting shape), to curve around the central sulci; the edge of these ''forceps'' form the upper part of the medial side of the posterior horn. The remainder of the medial edge of the ventricle is directly in contact with

white matter White matter refers to areas of the central nervous system (CNS) that are mainly made up of myelinated axons, also called tracts. Long thought to be passive tissue, white matter affects learning and brain functions, modulating the distributi ...

of the cortex of the occipital lobe.

Inferior horn of lateral ventricle

The inferior horn of the lateral ventricle, or ''temporal horn'', is the largest of the horns. It impinges on the

in a lateral and anterior direction, initially inferiorly, until it comes within 2.5 cm. of the lobe's apex; its direction is fairly well indicated on the brain surface by the

superior temporal sulcus The superior temporal sulcus (STS) is the sulcus separating the superior temporal gyrus from the middle temporal gyrus in the temporal lobe of the brain. A sulcus (plural sulci) is a deep groove that curves into the largest part of the brain, ...

. The horn lilts inferiorly towards its lateral edge. As a continuation of the interior side of the ventricular curve, the floor of the body of the ventricle becomes the roof of the inferior horn, hence the tail of the caudate nucleus forms the lateral edge of the inferior horn's roof, until, at the extremity of the ventricle, the caudate nucleus becomes the

amygdala The amygdala (; plural: amygdalae or amygdalas; also '; Latin from Greek, , ', 'almond', 'tonsil') is one of two almond-shaped clusters of nuclei located deep and medially within the temporal lobes of the brain's cerebrum in complex verte ...

. The stria terminalis forms the remainder of the roof, which is much narrower than at the body - the choroid plexus moves to the medial wall. The tapetum for the temporal lobe comprises the lateral boundary of the inferior horn, on its way to join the main tapetum above the body of the ventricle (passing over the Caudate Nucleus as it does so). The majority of the inferior horn's floor is formed by the fimbria hippocampi (from which the fornix emerges), and then, more anteriorly, by the

hippocampus The hippocampus (via Latin from Greek , ' seahorse') is a major component of the brain of humans and other vertebrates. Humans and other mammals have two hippocampi, one in each side of the brain. The hippocampus is part of the limbic system, ...

itself. As with the posterior horn, the remainder of the boundary - in this case the lateral side of the floor - is directly in contact with the white matter of the surrounding lobe.

Development

The lateral ventricles, similarly to other parts of the ventricular system of the brain, develop from the central canal of the neural tube. Specifically, the lateral ventricles originate from the portion of the tube that is present in the developing prosencephalon, and subsequently in the developing telencephalon. During the first three months of prenatal development, the central canal expands into lateral, third, and fourth ventricles, connected by thinner channels. In the lateral ventricles, specialized areas – choroid plexuses – appear, which produce

. The neural canal that does not expand and remains the same at the level of the midbrain superior to the fourth ventricle forms the cerebral aqueduct. The fourth ventricle narrows at the

obex OBEX (abbreviation of OBject EXchange, also termed IrOBEX) is a communications protocol that facilitates the exchange of binary objects between devices. It is maintained by the Infrared Data Association but has also been adopted by the Bluetooth S ...

(in the caudal medulla), to become the

central canal The central canal (also known as spinal foramen or ependymal canal) is the cerebrospinal fluid-filled space that runs through the spinal cord. The central canal lies below and is connected to the ventricular system of the brain, from which it r ...

of the

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the sp ...

. During development, pressure from exterior structures causes a number of concave bulges to form within the lateral ventricles, which can be extremely variable in their degree of development; in some individuals they are ill-defined, while in others they can be prominent: *from the ''forceps'' against the posterior horn - creating the ''bulb of the posterior cornu'' on the upper medial side of the horn *from the

calcarine sulcus The calcarine sulcus (or calcarine fissure) is an anatomical landmark located at the caudal end of the medial surface of the brain of humans and other primates. Its name comes from the Latin "calcar" meaning "spur". It is very deep, and known ...

against the posterior horn - creating the

calcar avis The calcar avis, previously known as the hippocampus minor, is an involution of the wall of the lateral ventricle's posterior cornu produced by the calcarine fissure. It is sometimes visible on ultrasonogram and can resemble a clot. Name The ri ...

(historically called the ''hippocampus minor'', for visual reasons) on the lower medial side of the horn *from the hippocampus against the inferior horn (on the medial floor of the horn) *from the

collateral sulcus The collateral fissure (or sulcus) is on the tentorial surface of the hemisphere and extends from near the occipital pole to within a short distance of the temporal pole. Behind, it lies below and lateral to the calcarine fissure, from which it ...

against the inferior horn - creating the Collateral eminence on the lateral floor of the horn. Fetal lateral ventricles may be diagnosed using linear or planar measurements.

Clinical significance

The volume of the lateral ventricles is known to increase with age. They are also enlarged in a number of neurological conditions and are on average larger in patients with

schizophrenia Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social wit ...

bipolar disorder Bipolar disorder, previously known as manic depression, is a mental disorder characterized by periods of depression and periods of abnormally elevated mood that last from days to weeks each. If the elevated mood is severe or associated with ...

major depressive disorder Major depressive disorder (MDD), also known as clinical depression, is a mental disorder characterized by at least two weeks of pervasive low mood, low self-esteem, and loss of interest or pleasure in normally enjoyable activities. Intro ...

and Alzheimer's disease. Asymmetry as an

anatomical variation An anatomical variation, anatomical variant, or anatomical variability is a presentation of body structure with morphological features different from those that are typically described in the majority of individuals. Anatomical variations are categ ...

, in the size of the lateral ventricles is found in about 5–12% of the population. This has been associated with handedness, where right-handed people have been found to have a larger right lateral ventricle and a longer left posterior horn, whereas left-handed people have been found to have longer right posterior horns. A severe asymmetry, or an asymmetry with

midline shift Midline shift is a shift of the brain past its center line. The sign may be evident on neuroimaging such as CT scanning. The sign is considered ominous because it is commonly associated with a distortion of the brain stem that can cause serious d ...

or diffuse enlargement, may indicate

brain injury An injury is any physiological damage to living tissue caused by immediate physical stress. An injury can occur intentionally or unintentionally and may be caused by blunt trauma, penetrating trauma, burning, toxic exposure, asphyxiation, or o ...

early in life, particularly in cases of a longer right posterior horn. If the production of cerebrospinal fluid is bigger than its reabsorption, or if its circulation is blocked – the ventricles may enlarge and cause

hydrocephalus Hydrocephalus is a condition in which an accumulation of cerebrospinal fluid (CSF) occurs within the brain. This typically causes increased pressure inside the skull. Older people may have headaches, double vision, poor balance, urinary inc ...

Calcification Calcification is the accumulation of calcium salts in a body tissue. It normally occurs in the formation of bone, but calcium can be deposited abnormally in soft tissue,Miller, J. D. Cardiovascular calcification: Orbicular origins. ''Nature Ma ...

of the choroid plexus can occur, usually in the atrium.

Additional images

File:Lateral ventricle small.gif, Position of lateral ventricles (shown in red). File:Gray735.png, Drawing of a cast of the ventricular cavities, viewed from above.

References

{{Authority control Ventricular system