LATERAL VENTRICLE

There are two large lateral ventricles, and one is present in each cerebral hemisphere. The ventricle is a roughly C-shaped cavity and may be divided into a

body - occupying parietal lobe anterior horn - occupying frontal lobe inferior horn - occupying temporal lobe posterior lobe - occupying occipital lobe

BODY OF LATERAL VENTRICLEExtends from the interventricular foramen posteriorly as far as the posterior end of the thalamus anteriorly.Consist of roof, floor and medial wall.

ROOF

Formed by the undersurface of the corpus callosum

FLOOR

Formed by the body of the caudate nucleus and the lateral margin of the thalamus.

MEDIAL WALL

Formed by the septum pellucidum anteriorly; posteriorly, the roof and the floor come together on the medial wall.

ANTERIOR HORNextends forward into the frontal lobe. It is continuous posteriorly with the body of the ventricle at the interventricular foramen. The anterior horn has a roof, a floor, and a medial wall

ROOF

Formed by the undersurface of the anterior part of the corpus callosum; the genu of the corpus callosum limits the anterior horn anteriorly.

FLOOR

Formed by the rounded head of the caudate nucleus

MEDIAL WALL

Formed by the septum pellucidum and the anterior column of the fornix

POSTERIOR HORNextends posteriorly into the occipital lobe

ROOF AND LATERAL WALL

Formed by the fibers of the tapetum of the corpus callosum.

MEDIAL WALL

Has two elevations:1. superior elevation: caused by the splenial fibers of the corpus callosum,

called the forceps major, passing posteriorly into the occipital lobe; this superior swelling is referred to as the bulb of the posterior horn

2. inferior elevation: produced by the calcarine sulcus and is called the calcar avis

INFERIOR HORNextends anteriorly into the temporal lobe The inferior horn has a roof and a floor.

ROOF

formed by the inferior surface of the tapetum of the corpus callosum and by the tail of the caudate nucleus

FLOOR

formed laterally by the collateral eminence, produced by the collateral fissure, and medially by the hippocampus

CLINICAL SIGNIFICANCE

Each lateral ventricle contains about 7 to 10 mL of cerebrospinal fluid. This fluid is produced in the choroid plexus of the lateral ventricle and normally drains into the third ventricle through the interventricular foramen (foramen of Monro). Blockage of the foramen by a cerebral tumor would result in distention of the ventricle, thus producing a type of hydrocephalus.

The choroid plexus of the lateral ventricle is continuous with that of the third ventricle through the interventricular foramen. The choroid plexus is largest where the body and posterior and inferior horns join, and it is here where it may become calcified with age. It is important that this calcification of the choroid plexus, as seen on radiographs, is not confused with that of the pineal gland