Lateral view of the lateral ventricle and surrounding structures. The corpus callosum is a semicircular band of commissural fibers and is anatomically divided into sections: the rostrum, genu, body and splenium. The C-shaped lateral ventricle can also be divided into subsections: the frontal horn, body, temporal horn, and the atrium situated just anterior to the occipital horn. The similarly C-shaped fornix lies within the curve of the lateral ventricle and rostrally emanates from the mamillary bodies. The fornix continues as the columns of the fornix, followed by the body of the fornix, the crus of the fornix, and transitions into the fimbria of the hippocampus. Between the fornix and the thalamus is an opening, the choroidal fissure, along the medial edge of the lateral ventricles which serves as an attachment site for the choroid plexus and through which the choroidal arteries penetrate. (Image courtesy of AL Rhoton, Jr.)