Sagittal section showing the corpus callosum

The corpus callosum is a large bundle of nerve fibers that connects the left and right hemispheres of the brain, allowing them to communicate and coordinate functions like senses, movement, and cognition. Composed of myelinated axons, it is the largest white matter structure in the brain and is divided into four parts: the rostrum, genu, body, and splenium. Conditions like agenesis of the corpus callosum (its absence) or surgical severing (callosotomy) can impair inter-hemispheric communication, leading to various neurological and cognitive issues.