Anatomical Aspects of the Agenesis of the Corpus Callosum in Man

The corpus callosum is the largest and phylogenetically one of the oldest of the commissures, yet its function is an enigma. In primitive mammals (edentata) it is formed by a thin membrane. In phylogenesis the corpus callosum becomes larger and larger. It is proportional to the growing size of the telencephalon and to the number of cerebral convolutions. Congenital absence of the corpus callosum in man is a rare occurrence. However, we have had the opportunity to observe 24 cases of agenesis of this commissure. The main purpose of this chapter is to demonstrate some typical variations of this pathological condition.