The early (primary) lesion of the microvasculature and neurons in the gray matter of the rat become mainfest within 0-3 min, long before the development of secondary ischemic-anoxic changes. The central hemorrhagic necrosis of the gray matter, induced by the impact injury, seems to depend primarily on theseverity of trauma. However, since the lesion is limited to the gray matter of one or two segments, these primary changes are not responsible for the irreversible transverse lesion. Additionally, the experimental cord injury in the rat demonstrates that secondary vascular changes (i.e., the pathological permeability of vessels in the white matter) produce a progressive edema that spreads into the necrotic zone and leads to definite transverse lesion. Not least of all, the increased pressure of the spinal tissue may promote the self-destructive process leading to irreversible damage to white matter.