Motor neurons reach from the brain to the spinal cord and from the spinal cord to the muscles throughout the body. They govern voluntary movements and muscle control.
ALS causes these motor neurons to degenerate over time until they eventually die. When the motor neurons die, the brain can no longer initiate and control muscle movement. When voluntary muscle action is progressively affected, people may lose the ability to speak, eat, move and breathe.
ALS was identified in 1869 by French neurologist Jean-Martin Charcot, but it became more widely known internationally in 1939 when it ended the career of one of baseball’s most beloved players, Lou Gehrig. For many years, ALS was commonly known as Lou Gehrig’s Disease.
“Amyotrophic” comes from the Greek language. "A" means no. "Myo" refers to muscle. "Trophic" means nourishment. So, amyotrophic means "no muscle nourishment,” and when a muscle has no nourishment, it "atrophies" or wastes away.
"Lateral" identifies the areas in a person's spinal cord where portions of the nerve cells that signal and control the muscles are located.
As this area degenerates, it leads to scarring or hardening ("sclerosis") in the region.