Cavum Septi Pellucidiet Vergae: Anatomic Finding and Review

Derived from the lateral part of the terminal bar, firstly, the septum binds to the frontal direction, always separated from the pallial part by a ventricular groove, a septumcortical fissure. This pre commissural part of the septum has a considerable thickness, especially in lower mammalians. As with the reptiles, their cells are grouped into two nuclei, the septi nuclei dorsolateral and ventromedial. It contains the fibers that ascend to the hippocampus (olfactory hyppocampal fibers or olfactory bundle of the septum). The pre commissural part continues backward, below the corpus callosum and over the foramen of Monro. This supra foraminal of the septum contains the fibers fornicais and cortico-habenulares. The extension of the corpus callosum allows an extension of the septum, whose pre commissural part is reduced as the measure that increases the frontal extension of the corpus callosum, while the supra foraminal suffers a stretching and a reduction still more important, as a result of the posterior displacement of the Amon horn. Such septum extension implies in its reduction to a fine membrane, the septum pellucidi of a man. Among the septal nucleus, the ventro medial nucleus, located in front of the anterior commissure, only maintains a remarkable volume. The bilateral septi can suffer coalescence or even a concrescence so that the arachnoid space, a septum cavity located between the septi of both sides, disappears. This process is almost normal in its posterior part. On the other hand, an increase of the arachnoid fluid can cause an expansion of the interseptal sub callosal space, including its posterior part, which, then, is transformed and becomes the cavity named Verga. However, it is evident that these cavities do not have any normal communication with the cerebral ventricles [1-3].