Refer to Figure 5 (below). Notice the area in the center of the spinal cord that is surrounded by a ring of connected astrocytes. This central area contains inflammatory cells and chemical mediators that kill the neurons and eventually form the glial scar that prevents migration of healing axons and neurons through this area. There is poor blood flow and swelling of the entire spinal cord. Neurons are dying, axons are severed, axons have lost their myelin sheath. The glial cells are dying (astrocytes and oligodendrocytes) and chemicals are being released that inhibit myelin from reforming and prevent healing of the axons. Note that some neurons and axons do however survive.
Figure 5. Spinal Cord Injury from IVDD in the Peracute and Acute Phase