This is a CT head demonstrating agenesis, or absence, of the corpus callosum. The corpus callosum is a broad band of axons interconnecting the two hemispheres of the brain. Agenesis of the corpus callosum, although rare, is one of the most common brain malformations in human beings. It can be completely asymptomatic, or it can be associated with autism, seizures, and motor, auditory and/or speech symptoms. The anterior corpus callosum has been noted to be more pronounced in musicians and left handed and ambidextrous people.