 The anatomy of the ventricles just want to remember you for some key facts. The first fact of all is that the form of the ventricles is dictated by the upfolding, by the cervical flexure, by the elongation of the cranial part of the neural tube with the cervical flexure and the cranial flexure. Originally it was just like a neural tube with a white lumen and a very small shell of neuroactoderm outside. The tube itself was filled already with liquid at early times. That was already necessary for the nourishment of the neuroactoderm. Later on blood vessels will take over and the liquid itself, the CSF, has no longer any nutritive function. Perhaps for the appenduma but most of the nourishment is done exclusively by the blood vessels. The hemisphero rotation dictates the form of the ventricles that we find later on in the spinal canal. It's still just a small narrow spinal or remnants of the neural tube whereas the rotation of the hemispheres dictates then the partition of the neural tube into the ventricles in the forebrain, mainly the lateral ventricles into the midbrain, the third ventricle, into the hindbrain, the fourth ventricle. So on this horizontal section that for instance here in the lateral ventricle with the anterior horn and posterior horn we find significant compressions by the basal ganglia here by the head of the nucleus caudatus and by the internal capsule with the anterior genu and the posterior genu and also in the frontal section we see the narrowing of that original neural tube by the caudate nucleus. So the ventricle cast shows us in detail how the compression was formed and here we can also with the anterior horn and the inferior horn, the posterior horn we can imagine that rotation towards the front, towards the back. Compression also in the third ventricle visible here by the interthermetic adhesion and also as a result of the hemisphere rotation we see that the insular is transferred to the midline and overwhelmed by the temporal and frontal part. We have some recesses, the supra-optical recess and the infundibular recess on the backside we have as a landmark the supra-pinal recess and the pineal recess. And then we have sometimes an indentation here that's indicative for the marking of the hypothalamic area that's the linear here, the hypothalamic area from the thalamic area. Then the connection of the aqueduct towards the fourth ventricle we go down to the fourth ventricle we see that we have the medial, the unpaired median aperture and the lateral aperture that brings the connection from the internal liqueur space to the external liqueur space we'll show that later on. The internal liqueur space contains about a third of the total contents between 30 and 40 milliliters. The total amount resting remaining two thirds are in the external subarachnoidal space and that has a certain reason, the reason is of course that we need to get buoyance of the brain. Otherwise that soft tissue of the brain if we didn't have these external liqueur spaces our brain or the basal parts of the brain would suffer like in the Cupidic ulcer but by the liqueur the mass of 1.3 to 1.5 kilograms is reduced to an effective weight of only 40 to 50 grams. So it's swimming the brain in that liqueur just like the embryo is swimming in the amniotic cavity in the uterus. Imagine if you didn't have that amniotic cavity in the uterus if you didn't have the amniotic fluid then the fetus would be compressed immediately with each cuffing or each intra-abdominal pressure rise. That's why it's protected, that's why we can see it. By the way when you look into embryology it's quite interesting in all these conditions when you have an hydramnion, if you have an oligohodra hydramnion then there is a compression in the first organ where you see the reason for the oligohodramnion is the kidney of course because the kidney doesn't produce enough urine so there's not enough amnion, amniotic fluid is urine. But the organ where it's visible is then the lung because the lung doesn't have enough space to expand because there is too much compression so it's evident in ultrasound first the hypoplastic lung and then secondly you think about it oh yeah the reason is a missing kidney or a hypoplegia of the kidney just like in the Potter syndrome. So buoyance of brain by the cerebrospinal fluid it's made possible because we have the choroid plexus the choroid plexus is mainly found in the lateral ventricles and in parts of the third ventricle and down to the fourth ventricle it's attached to this plexus by the tainia phonesis along the tainia phonesis we find the plexus and the plexus is attached there we can rip it off and then we can see the tainia formation itself basically it's a convolut of vessels of blood vessels that are lined by a cuboid epithelium that's an original section, that's the drawing so we see that the cuboidal epithelium has a brush border on top of it the brush border on top of it is for resorption and also for secretion and then it's underlaid by the blood vessels there's a small sub-epithelial layer that's going behind that brings up the cerebrospinal fluid basically when we compare the stuff, the serum and cerebrospinal fluid then we see that it's much more than a simple ultrafiltrate of the serum but I don't go now on this well, the sub-aurorheal space in these areas where the brain itself shows discrepancies, not a congruence between the frontal, medial and posterior skull base groove everywhere where we find some discrepancies between the outer brain and the skull there we find the cisterns, just like the inter-preduncular cistern or the cisterna macna so cisterns are nothing else than elongations of the basal part so where does the leak go to? before we start some showing of that it's resorbed or drained by the agnolation these agnogranations are found next to the superior sinus along the superior sinus direct connections of sub-aurorheal space through the veins corresponding veins, but that attributes for about 80% of the drainage about 20% of the drainage is going down into the spinal canal and then we have a peridural drainage where veins are connected to the interneural spains and sooner or later we get into the internal venous vertebral plexus which is connected to the external venous vertebral plexus then we have as a third possibility just an efflux via the dura pouches along the end of perinural tissue that's a perinural tissue which is accounting for a little bit less for that one last fact that we should mention here in that context is that the blood-brain barrier is differently constructed in the areas where we have the liqueur formation in the area where we have next to the ventricles where it's covered with epidermal cells then we see that between the epidermal cells there isn't transport from inside to outside but it's not possible to make a transport of highly molecular stuff from the inside of the vessels that are sub-jacent here because they are connected to the endothelial cells with tight junctions so tight junctions make it completely closed so we have an effective blood-brain barrier here in that case if we injected something, some dye intravescally into the vessels, the dye would not go over there it would only go into the areas where we have circumventricular organs like here they would get a faint staining outside because there in the periventricular organs or the circumventricular organs we don't have that blood-brain barrier Contrary to that, if you look into the areas where the plexus is there we find that the core plexus, these brush-balled epithelial cells are connected to each other with very dense tight junctions they do not permit any transport from inside to outside and that's clear otherwise we would have an enormous increase then we would have something like an ultra-filtrate of the sub-jacent vessels in order to make a possible access route from the vessel contents to the core plexus there we loosen where we have no tight junctions here in the vessels so it's a fenestrated endothelial cells so the fenestrations and intercellular gaps make it possible that these cells pick up the stuff from here and produce stuff so basically in these kind of areas the blood-brain barrier is shifted from the endothelial cells it's shifted towards the epithelial cells of the plexus that was proven at the old physiological experiment when you inject the dye into here then you get a nice superficial staining of the brain of the surface but you will not get a staining anywhere else in the body ok, so let's have a look on some peri-ventricular structures that you find here in the specimens that our colleagues from the Department of Anatomy provided so here we have the median section so here's a lateral ventricle here is largely invident seems to be an elderly patient must look like my brain with a hydrocephalus internal evacuo like an Alzheimer's brain what we see here is a prominence within the lateral ventricle the head of the caudate nucleus the nucleus caudatus and we can see when we go down here to the borderline here comes up the thalamus and then when we look down here we see something a blue line below here that's the thalamus striate vein which is demarcating here at that area also the borderline between the telencephalic caudate nucleus and the telencephalon itself and the diencephalon meaning the thalamus and then we go down here here's the inter-thalamic adhesion it's only a glia-cell bridge there was nothing, there's not a commissure or something like that it's only a glia-cell bridge and then we have here the hypothalamic sulcus then we proceed ventrally we find the supra-optic recess here's the supra-optic recess and here comes the infundibular recess here's the infundibulum or the rest of the infundibulum going down here's the hyperfusile stalk these are the areas where the supra-optic nuclei are located and here's the paraventricular nuclei giving rise for the hormones down to the searing, the adenohyper, the pituitary so going to the backside here's the suprapineal recess here's the pineal recess here's the forehead plate then we go down here into the aqueduct into the aqueduct into the fourth ventricle we do not see the apertures that we have here that close correlation between the brainstem, the cerebellum and the roof of the fourth ventricle so when we look on the lateral ventricle from caudally so you from caudally to the anterior horn to the posterior horn it's always immediately visible that this must be the posterior part and this is the anterior because the posterior horns go to the lateral because further down, if you go further downhill the ventricles have to circumnavigate the brainstem so the brainstem is impairing it so in the frontal area always the frontal horns are closer together than the posterior and temporal horn so here we can see it nicely here the brainstem is cut away so the frontal horn, here we go to the posterior horn it's in here here comes the temporal horn and it's a little bit cut down here I expected to see also the amygdala formation and the hippocampus area which is followed here by the inferior horn here we start with the deflection we go posteriorly then when we turn it around here again this coroid plexus that we can peel off here from the tainia that is remaining then if you turn it around we see the temporal horn marching towards the front and here comes already the hippocampal region the hippocampus is ascending in here folding here and this should be the nukle subterlamic constant okay so when we turn it around again we see that approaching of left and right so of left and right telomus here in that case there is also an intertelamic adhesion to be seen down here flip it back again then we have all the typical structures that we know from our first years neuroanatomy the telomus the head of the nucleus, caudatus of the caudate nucleus which is pretty big and the tail is that very small structure down here that side is visible yeah it's following up here and then we have of course the internal capsule which is separating the straight body from the telomus with the cruise anterior, the genu and the cruise posterior so I think these are the main structures I saw Dr. Ravi will pinpoint some other structures in his talk so I stop here thank you