ALS crim

This is a myelin-stained section of spinal cord from a patient who had amyotrophic lateral sclerosis (ALS). Symmetrical degeneration of corticospinal axons occurs secondary to degeneration of cerebrocortical motor neurons in ALS. When axons degenerate, myelin will secondarily be lost. The resulting reactive astrocytosis produces a firm scarlike alteration in the lateral (and anterior) corticospinal tracts or "lateral sclerosis".