Diffusion tensor imaging tractography overlaid on a T₁-weighted axial image (left) from a 12 year-old girl who had sustained a severe traumatic brain injury after falling from the back of a truck moving at low speed (initial Glasgow Coma Scale score=7) striking the back of her head and sustaining frontal contusions. Tractography and T₁-weighted magnetic resonance imaging from an age- and sex- matched child with orthopedic injury at approximately the same level is on the right. There is extensive frontal encephalomalacia in the child with traumatic brain injury at three months post-injury, but the real significance of the frontal damage is seen when tractography maps are created by seeding identical areas in the coronal plane, at a level just anterior to the genu of the corpus callosum in both children. The normal tracts from the frontal region at this level course posteriorly via central white matter pathways as well as the cingulum. Extensive interhemispheric projection across the anterior corpus callosum that includes an extensive network of integrated bifrontal pathways can be visualized in the child with orthopedic injury. All of these pathways are reduced and thinned in the child with traumatic brain injury. Note at this level, in the child with traumatic brain injury there was also an absence of callosal fibers across the posterior corpus callosum.