Here is the Comer-shaped structure, Corpus Callosum and that is the Septim Palusidum. This is the third ventricle. That is the fourth ventricle and this passage is the cerebral acuduct. Here the Septim Palusidum is removed so you can see the cavity. That is called lateral ventricle and the artery which is running here, you can see the anterior cerebral artery which runs. This is the ponds, medulla and cerebellum.