Schematic Representation of a Coup – Contrecoup Injury with Shearing
This exhibit shows a schematic representation of a coup – contrecoup brain injury with axon shearing. The force of an impact causes the head to suddenly hyperextend right, while the brain shifts to the left and strikes the skull interior (coup injury). The head then recoils to the left and stops sharply, causing the brain to shift right and strike the opposite skull interior (contrecoup injury). As the soft tissues of the brain repeatedly impact the ridged surfaces of the skull, the brain ripples and becomes misshapen. Diffuse axonal injuries also occur as a result of acceleration forces on the brain. Differing densities between the grey matter (neurons) and white matter (axons) causes them to shift at varying speeds, shearing the axons at the grey-white matter junction.