The cerebral cortex of eight patients with complicated head and brain traumatic injuries has been examined with light and transmission electron microscopes. The neuronal and neuroglial cell bodies and their processes have been examined to study the changes induced by the brain injury and the associated vasogenic and cytotoxic, moderate or severe, brain oedema. Light microscopy study showed oedematous and ischaemic neurons and neuroglial cells in both moderate and severe oedema, and breakdown of the blood-brain barrier with perivascular and parenchymatous haemorrhagic foci. Astrocytes and oligodendrocytes exhibited oedematous and reactive changes. At the electron microscope level oedematous changes were found in intraneuronal and glial somatic compartment. Myelinated axons showed clear and dark degenerative features. Beaded dendrites and clear and dense synaptic degeneration were also found. The extracellular space appeared distended, with the presence of clear and electron-dense haematogenous oedema fluid and fibrinous organization. Phagocytosis of degenerated myelinated axons and synaptic endings by neuroglial cells and non-nervous invading cells were observed. The clinical evolution time of traumatic brain injuries was considered in relation to nerve cell degenerative features.