The choroidal fissure is a narrow cleft in the medial part of the lateral ventricle, in a C-shaped arc, between the fornix and the thalamus, where the choroidal plexus join. Due to absence nervous tissue between ependima and pia-mater along this invagination, it is an important route in brain ventricles and cisterns. Five brains were studied by injecting colored silicone arteries and veins and five brains without colored silicone, in a total number of 20 brain hemispheres. it was analized and revised the neural, arterial and venous relationships and surgical approaches in all parts of the choroidal fissure, In conclusion, the previous knowledge detailed this microanatomy is primordial for neurosurgeons that will approach brain ventricular and cisternal lesions because the neurosurgeons gain a tridimensional notion that will be indispensable during surgery.633B801806