Remyelination after transient compression of the spinal cord.

Transient mild compression of the spinal cord produces a lesion in which demyelination with preservation of axon continuity is the predominant nerve fibre change. This damage is repaired by oligodendrocytes which produce complete though abnormally thin and short internodes of myelin along demyelinated stretches of axons. When compression is more severe, this damage is also repaired by Schwann cells which migrate into the spinal cord from nearby root entry zones and form complete segments of peripheral nervous system-type myelin around demyelinated central axons.