Ventricles and Location of the Cerebrospinal Fluid

Ventricles and Location of the Cerebrospinal Fluid The body of the lateral ventricle Extends from the interventricular foramen to the posterior end of the thalamus Roof: undersurface of the corpus callosum Floor: body of the caudate nucleus and the lateral margin of the thalamus Medial wall septum pellucidum Anterior horn of the lateral ventricle Anterior end: frontal lobe Posterior end: continuous with the body of the ventricle Roof: anterior part of the corpus callosum Floor: head of the caudate nucleus Medial wall: superior surface of the rostrum of the corpus callosum, septum pellucidum and the anterior column of the fornix Posterior horn of the lateral ventricle Anterior end: continuous with the body of the ventricle Posterior end: occipital lobe Roof and lateral wall : tapetum of the corpus callosum Medial wall: Superior: splenial fibers of the corpus callosum, forceps major Inferior: calcar avis Inferior horn of the lateral ventricle Anterior end: temporal lobe Posterior end: continuous with the body of the ventricle Roof : inferior surface of the tapetum of the corpus callosum, tail of the caudate nucleus and amygdaloid nucleus Floor: Laterally: collateral eminence Medially: hippocampus Third ventricle Anterior wall: lamina terminalis (thin sheet of gray matter) crossed by anterior commissure which is situated anterior to the anterior columns of the fornix Posterior wall: opening of cerebral aqueduct, posterior commissure, pineal recess, pineal body, habenular commissure Third ventricle Lateral wall: superiorly: medial surface of the thalamus Inferiorly: hypothalamus hypothalamic sulcus the interthalamic connection stria medullaris thalami. (bundle of nerve fibers, which are afferent fibers to the habenular nucleus) The corpus callosum The largest commissure of the brain, connects the two cerebral hemispheres (at the bottom of the longitudinal fissure) - Divided into: Rostrum: continuous with the upper end of the lamina terminalis Genu: bends inferiorly infront of the septum pellucidum Body Splenium The corpus callosum Forceps minor Radiation of the corpus callosum Forceps major Anterior commissure Crosses the midline in the lamina terminalis Smaller bundle (anterior) curves forward toward the olfactory tract. Large bundle (posterior) curves to reach the temporal lobes **plays a key role in pain and pain sensation??? Posterior commissure Crosses the midline immediately above the opening of the cerebral aqueduct into the third ventricle (involved in the pupillary light reflex)? Habenular commissure Crosses the midline in the superior part of the root of the pineal stalk connects the Habenular nuclie on both sides The fornix From the hippocampus to the hypothalamus. The nerve fibers first form the alveus, (thin layer of white matter covering the ventricular surface of the hippocampus), then converge to form the fimbria. Fornix The fimbriae of the two sides arch forward above the thalamus and below the corpus callosum to form the posterior columns of the fornix. The two columns then come together in the midline to form the body of the fornix The commissure of the fornix consists of transverse fibers that cross the midline from one column to another just before the formation of the body of the fornix. Projection Fibers Passing to and from the brainstem to the entire cerebral cortex Internal capsule: Anterior limb Posterior limb Genu - Medially: caudate nucleus and the thalamus - Laterally: the lentiform nucleus Projection Fibers Corona radiata: fibers emerging superiorly from between the nuclear masses Optic radiation: Most posterior Septum Pellucidum Thin vertical sheet of nervous tissue consisting of white and gray matter covered on either side by ependyma partition between the anterior horns of the lateral ventricles Septum Pellucidum Between the fornix and the corpus callosum. Between body of the corpus callosum and the rostrum.